Baking Soda vs Washing Soda: The Short Answer
Baking soda vs washing soda is a strength gap, not a brand gap. On the common pH figures of 8.4 and 11, washing soda (sodium carbonate) is about 400 times more alkaline than baking soda (sodium bicarbonate). Arm and Hammer calls for 1/2 cup per regular load and 1 cup for hard water, so keep baking soda for everyday odors.
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For greasy, grimy, or hard-water laundry, the box I would start with is Arm and Hammer Super Washing Soda. For plain odor control on everyday clothes, the gentler pick is regular Arm and Hammer Baking Soda. Most homes that wash a lot end up owning both.
Below you’ll find the chemistry behind the gap, the doses printed on Arm and Hammer’s own page, where borax and OxiClean fit, and a scale check for turning baking soda into washing soda at home. Every label claim here comes from the Arm and Hammer directions page, a listing, or a safety data sheet I read on October 22, 2026, and each one is named where it appears.
Short on time? Jump to the job you need done.
What’s in This Guide
- The Short Answer
- Top Picks at a Glance
- What Is Washing Soda?
- The 1 Flaw: Scooping Washing Soda Like Baking Soda
- Difference Between Baking Soda and Washing Soda
- Washing Soda vs Baking Soda: Match the Box to the Soil
- Arm and Hammer Super Washing Soda: Dose, Presoak, and Fabric Limits
- The 4 Laundry Boosters, Reviewed
- Washing Soda vs Borax
- How to Make Washing Soda From Baking Soda
- Where Can I Buy Washing Soda?
- Side-by-Side Comparison
- Which Box Fixes Which Problem?
- Which One Should You Choose?
- Frequently Asked Questions
- Final Verdict
Baking Soda vs Washing Soda: Top Picks at a Glance
Here is the baking soda vs washing soda shortlist, plus the two boosters most often weighed against them. The difference between baking soda and washing soda decides which one leads. Listing text for each was read on October 22, 2026, and the dose and caution lines come from the label pages named in each section.
| Product | Best for | Active ingredient | Buy |
|---|---|---|---|
| Arm and Hammer Super Washing Soda (55 oz) | Grease, heavy soil, hard water | Sodium carbonate | Check Price |
| Arm and Hammer Baking Soda (2.7 lb) | Everyday odors, mixed fabrics | Sodium bicarbonate | Check Price |
| Harris Borax Powder (1.5 lb, unscented) | Hard-water boost, towels and sheets | Borax (listed as 100% pure 5 mol borax) | Check Price |
| OxiClean Versatile Stain Remover Powder (5 lb) | Tough stains, presoaks | Sodium carbonate plus sodium percarbonate | Check Price |
Listing checked October 22, 2026, for the top pick. Sizes are the exact tiles linked, and each product page lists other sizes too.
What Is Washing Soda, and Why Is It About 400x More Alkaline?
Washing soda is sodium carbonate (Na2CO3), a grainy white powder sold for laundry and heavy cleaning. Arm and Hammer says it contains sodium carbonate and water, and that it should not be confused with sodium bicarbonate, the chemical name for baking soda.
So what is washing soda in chemistry terms? Take baking soda (NaHCO3), swap its hydrogen atom for a second sodium atom, and you have washing soda.
The pH gap is the whole story. Hunker, in an article syndicated on AOL, gives baking soda a pH of 8 and washing soda a pH of 11. RawSource, a chemical supplier, lists 8.0 to 8.6 for a 1% baking soda solution and 11.37 for a 1% washing soda solution.
The pH scale is logarithmic, so every whole step is 10 times the hydroxide. I use 8.4 for baking soda, which sits inside RawSource’s range, and 11 for washing soda. That gives 10 to the power of 2.6, or about 400 times.
Other published pairs land between roughly 600 times and 2,300 times, so treat 400x as the low end of the gap and not a lab constant. Even at the low end, the same scoop of each powder is a very different tool.
Arm and Hammer says the extra alkalinity breaks down dirt and grime, and that sodium carbonate binds to the minerals that make water hard. That frees your detergent to grip fibers instead of fighting minerals.
MedlinePlus lists washing soda and soda ash as the same chemical and names automatic dishwashing soaps and some bleaches among its sources, so the powder is less exotic than the box suggests. You’ll see it again across our cleaning chemicals and solutions reviews.
The 1 Flaw: Scooping Washing Soda Like Baking Soda
The flaw in baking soda vs washing soda is a habit. You reach for whatever white powder is closest, and the scoop treats a 400x alkalinity gap like a rounding error.
Label doses show how much the scoops differ. Arm and Hammer’s page calls for 1/2 cup of Super Washing Soda in a regular load and 1 full cup for hard water or large, heavily soiled loads. The Harris Borax listing asks for one 2 oz scoop, so none of these numbers transfer from one powder to another.
The same Arm and Hammer page says to test a hidden spot for colorfastness before pre-treating, to wear gloves, and to keep washing soda off aluminum cookware and fiberglass bathroom fixtures. A permies.com poster named Jill Dyer adds a fabric rule of her own, “keep it away from wool in large concentrations.”
Stiff gray towels left behind in a rental linen closet are a familiar sight at move-out, and hard water plus the wrong booster is often part of the story. Our guides on making towels soft again and why towels smell after washing cover the wash sequence.
Three checks before you pour a washing soda dose.
- Fabric label first. If the care label says dry clean only, skip every powder in this guide.
- Water hardness next. Hard water moves Arm and Hammer’s dose from 1/2 cup to 1 cup.
- Soil level last. A large, heavily soiled load gets the same 1 cup dose.
Difference Between Baking Soda and Washing Soda: 6 Traits That Change Your Wash
Here is the difference between baking soda and washing soda once the powder hits the machine. The pH, dose, and caution rows matter most.
| Trait | Baking soda | Washing soda |
|---|---|---|
| Chemical | Sodium bicarbonate (NaHCO3) | Sodium carbonate (Na2CO3) |
| pH, working figures | About 8.4 (8.0 to 8.6 at 1%) | About 11 (11.37 at 1%) |
| Edible | Food grade, per the Arm and Hammer listing | No, keep it away from food |
| Typical laundry job | Everyday odors | Grease, heavy soil, hard water |
| Label dose per load | Baking soda doses by washer type | 1/2 cup, or 1 cup for hard water or heavy soil |
| Cautions on pages read | Follow the garment care label | Gloves, colorfastness test, no aluminum cookware, no fiberglass bathroom fixtures |
In a washing soda vs baking soda swap, 1/2 cup of each is not an equivalent dose. They work at very different strengths, and the stronger one carries the longer caution list.
If odor is your only problem, the milder side of baking soda vs washing soda is usually enough. For the rest of your routine, our laundry care guides cover detergents, stains, and boosters one problem at a time.
Washing Soda vs Baking Soda: Match the Box to the Soil
The washing soda vs baking soda decision gets easier once you name the soil. Most people reach for a booster because a load smells, but smell is a symptom. Sour gym shirts, musty towels, and greasy kitchen rags each have a different cause.
- Light odors on mixed fabrics point to baking soda. The Arm and Hammer baking soda listing sells deodorizing across 100+ household uses.
- Grease and heavy soil point to washing soda at the 1 cup heavy-load dose, since Arm and Hammer ties that dose to large, heavily soiled loads.
- Hard-water stiffness points to washing soda or borax. Arm and Hammer says washing soda binds hardness minerals, and the Harris listing sells borax as a hard-water laundry booster.
- Tough stains point to OxiClean, which adds oxygen bleach on top of sodium carbonate.
The baking soda vs washing soda choice also changes by fabric, so check the care label before any powder.
Stains that already went through a dryer are a separate problem. A dedicated stain remover for old set-in stains reaches them better, and our roundup explains which formulas to pick.
If towels carry buildup rather than a single stain, a laundry stripping routine is the reset to try before adding more booster.
Arm and Hammer Super Washing Soda: Dose, Presoak, and Fabric Limits
If you’re asking what is washing soda used for, the Arm and Hammer directions page lists laundry, bathroom, oven, grill, and garage jobs. This table covers the laundry doses, and the page carries a 2019 copyright, so doses on the box in your hands win if they differ.
| Job | Arm and Hammer’s stated dose |
|---|---|
| Regular load | 1/2 cup with your usual detergent, at the start of the cycle |
| HE washer | 1/2 cup in the HE dispenser with your usual detergent |
| Large, heavily soiled load, or hard water | 1 full cup with your usual detergent |
| Presoak in a tub | 2 tablespoons per gallon of warm water, at least 30 minutes |
| Presoak in a filled washer | 1/2 cup, then 1/2 cup more in the wash cycle |
| Spot paste | 4 tablespoons washing soda and 1/4 cup warm water, rubbed in with gloves |
| DIY laundry soap | 2 cups washing soda, 1/2 cup baking soda, one shredded soap bar, then 1/4 cup per load |
The presoak math is worth a second look. A tub presoak uses 2 tablespoons for a gallon, while a filled washer takes a full 1/2 cup, because a washer holds many gallons. Scaling the tub dose by hand is how people end up with either a weak soak or a gritty one.
If your wash runs cold, dissolve the dose in a jar of warm water first and pour that in. It avoids undissolved grit sitting at the bottom of the drum, and it costs you a minute.
The DIY soap recipe is the one place Arm and Hammer pairs the two boxes. If you’d rather skip mixing, our eco friendly laundry detergent roundup covers ready-made options.
Surfaces have limits as well. Arm and Hammer’s page says it can clear grease or oil spills on concrete, using a paste left overnight, so a pass with a shop vac for the garage first clears the dry debris. More floor tools sit in our vacuums and floor care section.
For sealed counters and stovetops, the best all purpose cleaner for your surface is the gentler choice. And if a front loader keeps a film after boosters, check front load washer mold before blaming the powder.
The 4 Laundry Boosters, Reviewed
Two of these boxes are the baking soda vs washing soda pair itself. The other two are the boosters people weigh against them. The difference between baking soda and washing soda shows up in the dose, so every spec below comes from labels, listings, and a safety data sheet.
1. Arm and Hammer Super Washing Soda: Best for Grease and Hard Water
| Spec | Detail |
|---|---|
| Active ingredient | Sodium carbonate |
| Size linked | 55 oz box (Pack of 1) |
| Scent | Fragrance-free, phosphate-free (listing) |
| Label dose | 1/2 cup per load, 1 cup for hard water or heavy soil |
| Presoak | 2 tablespoons per gallon, 30 minutes or more |
| Listing claim | Up to 15% better liquid detergent performance, tied in the fine print to mustard and blood stains against a leading value detergent alone |
This is the box the whole baking soda vs washing soda comparison hinges on. Read the 15% claim as a narrow result for two stains, not a promise for every load.
I’ve used Arm and Hammer Super Washing Soda as a laundry booster for more than three years, and the softer-water effect is why it stays on my shelf. If you run cold washes, search the listing’s reviews for the word dissolve before you buy, and use the warm-jar method above.
I haven’t found a named plumbing source that settles whether washing soda is safe for drains, so this post does not recommend it as a drain treatment.
Skip it if you want a scented booster, because the listing says fragrance-free.
Linked tile is the 55 oz Pack of 1. A 2-pack tile exists too, so check the tile before adding to cart.
2. Arm and Hammer Baking Soda 2.7 lb: Best for Everyday Odors
| Spec | Detail |
|---|---|
| Active ingredient | Sodium bicarbonate, USP grade (listing) |
| Size linked | 2.7 lb resealable bag (43.2 oz tile) |
| Additives | None, no cornstarch, no fragrance (listing) |
| Uses listed | 100+ household uses, cleaning and deodorizing |
In any baking soda vs washing soda matchup, this is the lower-risk box to reach for by default. It suits loads where nothing is greasy and nothing is stiff, and the leftovers go to the fridge, the sink, or the oven.
Any bagged powder can arrive torn, so open the carton on arrival.
Skip it if hard water or grease is the real problem, since Arm and Hammer’s page credits washing soda, not baking soda, with binding hardness minerals.
Linked tile is the 2.7 lb (43.2 oz) bag from the listing title. A 7 lb tile and a 4-pack tile exist, so check the tile before adding to cart.
3. Harris Borax Powder: Best Partner for Hard Water
| Spec | Detail |
|---|---|
| Ingredient | Listed as 100% pure 5 mol borax, no fragrances or additives |
| Size linked | 1.5 lb (24 oz) bag, unscented, scoop included |
| Label dose | 1 scoop (2 oz) per load |
| Presoak | Not stated on the page read |
| Listing claim | Cleans up to 20 loads, sold as a hard-water laundry booster |
Borax sits outside the baking soda vs washing soda pairing, but it’s the other powder people reach for when towels go stiff. The Harris listing says it neutralizes hard water’s effect on detergent and says the scoop works on delicates too.
The listing’s own numbers don’t line up. Twenty loads from a 24 oz bag works out to 1.2 oz per load, calculated from the listing, while a 2 oz scoop per load would empty the bag in 12 loads. Measure from the bag’s directions and your scoop before you trust the 20-load figure.
Treat it like washing soda on storage, labeled and out of reach of kids and pets. The page I read states no cautions, so I can’t quote any.
Skip it if you want a presoak dose, because the page I read gives only the per-load scoop.
Linked tile is the 24 oz (1.5 lb) Pack of 1. A 3-pack and a 160 oz tile exist, so check the tile before adding to cart.
4. OxiClean Versatile Stain Remover Powder: Best for Tough Stains
| Spec | Detail |
|---|---|
| Composition (SDS, 2020) | 55 to 70% disodium carbonate, 30 to 40% sodium percarbonate, 1 to 5% ethoxylated alcohols |
| Size linked | 5 lb tub (80 oz tile) |
| pH (SDS) | 10.5 in a 1% solution |
| Appearance (SDS) | White to off-white powder with blue specks, no odor listed |
| Listed as | Oxygen-powered, color safe, chlorine free |
OxiClean lands in the middle of the washing soda vs baking soda question, because more than half the tub is washing soda. Its 2020 safety data sheet lists 55 to 70% disodium carbonate and 30 to 40% sodium percarbonate, the oxygen-powered part of the formula.
That peroxide is why it’s sold for tough stains, which plain washing soda doesn’t claim to bleach. The SDS also lists the powder as causing serious eye damage and names strong acids, strong bases, and strong oxidizers as incompatible, so keep it away from chlorine bleach and follow the tub’s own mixing warnings.
The SDS describes blue specks in the powder, so dissolve it fully before it touches fabric.
Skip it if you want no oxygen bleach in the load, because 30 to 40% of the SDS composition is sodium percarbonate.
Linked tile is the 80 oz (5 lb) Pack of 1. A 48 oz tile and a 2-pack exist, so check the tile before adding to cart.
Washing Soda vs Borax: Which One Belongs in Your Wash?
Once the baking soda vs washing soda question is settled, this is the next one people ask. Both are sold as hard-water laundry boosters, and they are different minerals with different label details.
| Trait | Washing soda | Borax |
|---|---|---|
| Chemical | Sodium carbonate | Borax, listed as 5 mol borax |
| Label dose per load | 1/2 cup, 1 cup for hard water | 1 scoop (2 oz) |
| Presoak | 2 tablespoons per gallon, 30 minutes or more | Not stated on the Harris page |
| Label cautions on pages read | Gloves, colorfastness test, no aluminum cookware | None stated on the Harris page |
| Source | Arm and Hammer directions page | Harris Amazon listing |
Look at the units. Arm and Hammer measures by volume in cups, while Harris measures by a 2 oz scoop, so you can’t swap one dose for the other by eye. That gap is one more reason to stick with a single powder at its own label dose before stacking a second.
My pick is washing soda for grease and hard water, and borax when you want a fixed per-load scoop. Plenty of DIY recipes combine them, and Arm and Hammer’s own DIY soap pairs washing soda with baking soda.
How to Make Washing Soda From Baking Soda (and Check It Worked)
Heat drives water and carbon dioxide out of baking soda and leaves sodium carbonate behind, which is why the baking soda vs washing soda gap is chemistry and not branding. Arm and Hammer notes you can use baking soda to make a DIY washing soda, and RawSource says baking soda begins to decompose above 50 degrees C.
The chemistry gives you a number to check. Two baking soda units weigh 2 x 84.007 g/mol and become one washing soda unit at 105.988 g/mol, so you keep about 63% of the starting weight. That figure is calculated from RawSource’s molar masses.
- Weigh your starting powder. Use a kitchen scale and write the number down, for example 16 oz.
- Spread it thin. Use a rimmed baking sheet you don’t use for food, with a layer about 1/2 inch deep or less.
- Bake at 400°F. Stir every 15 minutes and plan on 30 to 60 minutes.
- Weigh it again. You’re done when the weight stops dropping near 63%, about 10.1 oz from 16 oz. If it’s higher, bake 15 more minutes and weigh again.
- Cool and label. Use an airtight container marked WASHING SODA so nobody mistakes it for a pantry item.
The 400°F figure comes from home recipes, not from a manufacturer page, which is why the scale matters more than the clock. RawSource also cites one source that puts complete decomposition near 270 degrees C, higher than a 400°F oven, so a batch that stalls above 63% is worth another round.
Arm and Hammer draws one more line here. It calls soda ash the anhydrous form of sodium carbonate, like a more concentrated washing soda, and an oven-dried batch has lost its water. No source I read gives a weight for a 1/2 cup scoop of either, so a homemade batch has no verified dose, and the box’s 1/2 cup shouldn’t be copied blindly.
Is it worth doing? A 2.7 lb bag of baking soda yields about 1.7 lb of washing soda, calculated from the 63% figure, and the boxed product is widely stocked. I’d only bake it when you’re out and need a load done today, and I’d wear gloves because it’s no longer food safe.
Where Can I Buy Washing Soda?
Where can I buy washing soda is a fair question, because it rarely sits next to the baking soda. Look in the laundry aisle near the other boosters for the Arm and Hammer Super Washing Soda box. The same box is on Amazon, and the review above links the exact tile.
Pool supply aisles are the other answer, since they sell sodium carbonate as a pH increaser. If you go that route, confirm sodium carbonate is the only listed ingredient. A pool bag isn’t labeled for laundry, so every dose and fabric caution in this guide comes from Arm and Hammer and not the pool brand.
When a store is out, the baking soda vs washing soda gap still has a workaround. So what is washing soda’s closest cousin on the shelf? OxiClean Versatile works as a partial stand-in, since more than half of it is sodium carbonate by its safety data sheet.
It adds sodium percarbonate, so it’s not a like-for-like swap.
Baking Soda vs Washing Soda: Side-by-Side Comparison
Here is the baking soda vs washing soda comparison in one grid, with the two rivals beside it.
| Super Washing Soda | Baking Soda | Harris Borax | OxiClean Versatile | |
|---|---|---|---|---|
| Active ingredient | Sodium carbonate | Sodium bicarbonate | 5 mol borax | Sodium carbonate plus percarbonate |
| pH on pages read | About 11 | About 8.4 | Not stated | 10.5 at 1% (SDS) |
| Best job | Grease, hard water | Everyday odors | Hard-water boost | Tough stains |
| Regular load dose | 1/2 cup | See our baking soda guide | 1 scoop (2 oz) | Follow the tub label |
| Cautions on pages read | Gloves, no aluminum cookware | None listed | None stated | Serious eye damage, SDS |
| Buy | Check Price | Check Price | Check Price | Check Price |
The four picks answer four different jobs, so the job you need done settles baking soda vs washing soda and the two rivals. Mixed pH bases explain the table: the 11 and 8.4 are working figures, while the 10.5 is a 1% solution from the SDS.
Baking Soda vs Washing Soda: Which Box Fixes Which Problem?
This is the baking soda vs washing soda decision turned into a lookup, and the difference between baking soda and washing soda is easiest to see by problem. Find yours in the first column, then use the dose each source states.
| Problem | Grab this | Dose | Why it fits |
|---|---|---|---|
| Musty or stiff towels | Washing soda | 1/2 cup, 1 cup in hard water | Arm and Hammer says it binds hardness minerals |
| Sour smell on mixed synthetics | Baking soda | Per our baking soda guide | Gentler default for mixed loads |
| Greasy kitchen towels, work clothes | Washing soda presoak | 2 tbsp per gallon, 30 minutes or more | Matches Arm and Hammer’s presoak |
| Everyday dirt and tough stains | OxiClean | Follow the tub label | Adds sodium percarbonate |
| Stiff sheets, dull whites | Harris Borax or washing soda | 1 scoop, or 1/2 to 1 cup | Both are sold as hard-water boosters |
| Wool, silk, or dry-clean-only | None of these | Follow the care label | Check the garment before any alkaline powder |
Never add any of these to a load that already has chlorine bleach unless the label allows it. Our Fabuloso vs Pine Sol breakdown shows how fast a mixing mistake turns dangerous.
Vinegar is the other trap. It’s an acid and washing soda is an alkali, so pouring both into one cycle neutralizes them, and you mostly get fizz and wasted product.
Baking Soda vs Washing Soda: Which One Should You Choose?
Pick by job, because washing soda vs baking soda is a job question and not a loyalty one.
Arm and Hammer Super Washing Soda
- Pick it for greasy or heavily soiled cotton loads.
- Pick it if your water leaves film on glasses and stiffness on towels.
- Skip it for dry-clean-only items and anything that fails a colorfast test.
Arm and Hammer Baking Soda
- Pick it for everyday odor control on mixed loads.
- Pick it if you want one box that also covers the fridge and the kitchen sink.
- Skip it when grease or hard water is the real problem.
Harris Borax Powder
- Pick it for stiff towels and sheets.
- Pick it if you want a fixed per-load scoop beside a washing soda routine.
- Skip it if you need a presoak dose, since the page gives only the scoop.
OxiClean Versatile Stain Remover Powder
- Pick it for tough stains and presoaks.
- Pick it if you want washing soda and oxygen bleach in one scoop.
- Skip it if your routine uses chlorine bleach in the same load.
Frequently Asked Questions
Three questions come up most after the baking soda vs washing soda comparison.
Can I use baking soda instead of washing soda?
Yes for light odor control, but not for grease, hard water, or heavy soil, because washing soda is about 400 times more alkaline on the common pH figures. If a recipe needs washing soda’s strength, bake the baking soda until the scale shows about 63% of its starting weight.
- The swap works for freshening lightly soiled everyday clothes.
- The swap fails on greasy work clothes and stiff hard-water towels.
- The real fix is converting it in the oven with the scale check above.
Is washing soda the same as soda ash?
Mostly yes. Arm and Hammer calls them the same thing, with soda ash being the anhydrous form of sodium carbonate and washing soda the version combined with water, so soda ash is like a more concentrated washing soda.
- MedlinePlus lists washing soda and soda ash as the same chemical.
- Pool soda ash is sold as a pH increaser with no laundry directions.
- Read the ingredient line and buy it only if sodium carbonate is the sole ingredient.
Is washing soda toxic?
Not in small amounts, but it irritates skin and eyes and is not for eating. MedlinePlus says sodium carbonate is usually not very toxic in small amounts, though swallowing large amounts can cause serious symptoms.
- Wear gloves when you handle it, as Arm and Hammer’s page advises.
- If swallowed the same page says to rinse your mouth and contact a physician.
- For any exposure the national Poison Help line is 1-800-222-1222, per MedlinePlus.
Final Verdict
In the baking soda vs washing soda matchup, washing soda wins any load with grease, heavy soil, or hard water. Baking soda wins the everyday odor loads where gentleness matters more than power. If a busy household buys one box, make it Arm and Hammer Super Washing Soda at the 1/2 cup label dose, and move to 1 cup only for hard water or heavy soil.
Add Harris Borax if towels still come out stiff, and add OxiClean if the problem is stains rather than soil. Store whichever you pick labeled and out of reach, and keep the Poison Help number, 1-800-222-1222, where you’d look for it.
For more head-to-heads, browse our laundry care guides, read how I research every review, or see the types of cleaning products we cover.
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