Washing Soda vs. Baking Soda: What's the Difference and Which Is Better for Laundry?

Are you here because you’ve fallen down the black hole that is #CleanTok? And are you now questioning and rethinking your entire cleaning routine, including the products you own? If you’ve set your investigative sights on baking soda and washing soda at the moment, wondering how they could really be that different, then know that you’re not alone. 

The two items are sometimes used interchangeably in speech and in their applications by many. This switcheroo is pretty understandable—they’re both powdery, white substances and contain “soda” in their names. Plus, they’re both considered old-school cleaning products, used frequently in homemade solutions like scrubs and deodorizers. (Washing soda in particular has had a resurgence with the rise of laundry stripping, a cleaning technique that took hold of TikTok in 2020 and has lingered ever since.) So they’re similar, but they’re not the same.

To clear up the confusion between the two ingredients, we spoke to the product leader in the categories, Arm & Hammer, the brand that’s nearly synonymous now in most households with baking soda and washing soda. We also chatted with a dry-cleaning professional (and laundry product-testing wizard!) for their tips on how to optimize the performance of each product. Without further ado, let’s explore the “washing soda versus baking soda” debate.

What Is Washing Soda?

Washing soda (or soda ash, as it’s sometimes called) is technically sodium carbonate (Na₂CO₃), and it’s a naturally occurring chemical compound. In fact, washing soda was historically created from plant ash. Nowadays, most washing soda is mined. Lisa Muentener, a research and development expert from Arm & Hammer, confirmed washing soda is currently extracted from trona ore in the United States. (Trona is a mineral, and the largest deposit in the world is actually in Wyoming.)

According to Muentener, washing soda is extremely alkaline with a pH of 11, which makes it highly effective at stain and grease removal. For context, dish soap’s pH levels are between 7 and 10, while bleach’s pH range is 11 to 13. So washing soda is more powerful than dish soap, and nearly as potent as bleach, which explains why it’s remained a staple in so many cleaning caddies.

Zachary Pozniak, the vice president of operations of dry cleaning service Jeeves New York, rigorously tests countless laundry products on social media and confirmed that washing soda is even a main component in most powdered detergents. “It’s a stronger base than its cousin, sodium bicarbonate (or baking soda),” he says.

Household Applications

Washing soda is primarily used to remove greasy dirt and food stains from clothes, and it enhances the performance of your other laundry products by softening hard water, which has a reputation for disrupting detergent solubility. (Basically, detergent has a tough time lathering up in the machine and doing its job in hard water.) Plus, hard water leaves behind a mineral residue that builds up over time, eventually making clothes feel stiff, so washing soda would be able to mitigate some of those effects as well. 

Pozniak recommends adding washing soda directly into the drum of your machine prior to loading clothes (read package instructions for dosing). But his preferred use for the ingredient is actually in a laundry boosting “cocktail” for extra smelly or soiled loads—he combines equal parts borax, powdered oxygen bleach, and washing soda and adds about ¼ cup of the mix to a full load. Try not to go overboard with the stuff though. According to Pozniak, “These boosters can accelerate textile deterioration if used in excess.”

And, as if being a laundry star wasn’t enough, washing soda can also be used to clean kitchen surfaces and appliances, pots and pans, and upholstery. 

What Is Baking Soda?

Baking soda is sodium bicarbonate (NaHCO₃). Muentener explains in this chemical formula, there’s half the sodium of sodium carbonate (washing soda), which means baking soda and washing soda are chemically quite similar. Actually, most baking soda is derived from washing soda! Sodium carbonate that’s been extracted from the mined trona ore is transformed into sodium bicarbonate when carbon dioxide is infused during the manufacturing process.  

Baking soda is slightly alkaline or basic and has a pH of 8.4. According to Muentener, baking soda is chemically special in that it has the ability to act as both an acid and a base. “It can neutralize both acidic and basic volatile odors by turning them into non-volatile salts,” she says. This is why baking soda is such a boss at combating so many types of funky aromas.

Household Applications

Besides being a baking staple thanks to its leavening power, baking soda is used as a cleaning agent throughout the home. You’ll see it used to deodorize refrigerators, litter boxes, upholstery, carpeting, and in laundry. Baking soda is also often transformed into a paste, functioning as a scratchless scouring scrub for all kinds of surfaces, from ceramic to stainless steel. 

Baking soda doesn’t have quite the same reputation in the laundry room as washing soda, but Pozniak contends that it can be effective in the wash (beyond its odor-blasting capabilities) if used correctly. It’s much milder than washing soda, yes, but it can still help raise the pH of the wash water to boost detergent efficacy, and according to Pozniak, “Baking soda is one of the best ways to remove particulate stains—think dirt, mud, and sand—because it breaks up metallic bonds.” Instead of using it for soaking like most DIY solutions instruct, Pozniak recommends adding it to the washing machine drum for better results. (We suggest about ½ cup.)

Key Differences Between Baking Soda and Washing Soda

We mentioned earlier that baking soda and washing soda have very similar chemical compositions—but they’re not the same and they’re not always interchangeable. (Please, never use washing soda in a recipe.) Let’s go over the differences between the two. 

Physical Differences 

When it comes to texture, Muentener confirms that baking soda is bright white or off-white and typically has a fine and powdery texture, “similar to that of flour or powdered sugar.” On the other hand, washing soda tends to have larger and coarser crystals or granules, she says. It’s more grainy, and may have a dull or grayish hue. “Washing soda may appear less ‘pure’ or ‘clean,’ compared to baking soda,” Muentener explains. 

Functional Differences

Because washing soda is more caustic than baking soda due to its high pH, it’s mostly used in laundry to remove stains, soften water, and boost detergent efficacy. It’s not used as liberally as baking soda because it’s harsher. Muentener advises handling washing soda with caution as it may be damaging to skin and eyes, so gloves might not be a bad idea if your skin is especially sensitive. 

Baking soda has a bit more versatility outside of the laundry room. It’s an essential baking ingredient, of course, but it’s an effective deodorizer around the home too. It’s also used in many scrubs—a popular combination is baking soda and hydrogen peroxide, which whitens and lifts stains from a variety of surfaces like grout lines.

Is Baking Soda or Washing Soda Better for Laundry?

Baking soda is commonly used alongside detergent to fix stinky loads, and it can boost detergents as well as bust some stains, but washing soda is the typical go-to for most tough laundry jobs. Baking soda is gentler than washing soda, so it won’t be as efficacious. Think of washing soda as a more amped-up version of baking soda. Washing soda can do a better job of removing stains and brightening clothes—there’s a reason why it’s usually included in laundry stripping recipes and baking soda isn’t. But it can be harsh on fabric as Pozniak mentioned earlier, especially when compared to baking soda, if used in excessive amounts and too frequently. Limit your use of washing soda to extend the life of your fabrics.