This DIY Laundry Detergent made with liquid castile soap is SO cheap & easy to make with just a few natural ingredients. It’s the perfect non-toxic alternative to store-bought detergent!

I’ve been making my own laundry soap for years now and use it for everything in my front-loading washer, including my husband’s dirty work clothes and even my cloth diapers. It’s a great way to save some money and cut down on toxins in our home. It works wonderfully and is SO much cheaper than the store-bought detergents…especially if you’re buying the “natural options” – those are some expensive detergents and the cost adds up quickly, especially if you have a large family. Plus, it’s so easy to make and lasts forever when you make a big batch in a 5-gallon bucket. This recipe can be used in any washing machine – regular or HE (high efficiency washers).

The absolute cheapest way to make this laundry soap is by grating up and melting castile bar soap before adding it to the detergent mix, but using liquid castile soap as we will in this recipe is quicker and easier. Even though it does cost just a tiny bit more to use liquid castile soap, it’s still insanely cheap compared to the “natural” store-bought stuff.

I made a big batch of my own homemade laundry soap in this video while doing lots of other tasks in the kitchen, check it out for a video tutorial and to see just how simple it is to make!

HOW LONG DOES HOMEMADE LAUNDRY DETERGENT LAST?

This recipe makes one gallon of DIY liquid laundry soap using liquid castile soap and if you use 1/4 cup per load (what I use in my HE machine) you’ll get 64 loads of laundry per gallon. I usually make a 4x batch and store it in a 5-gallon bucket. So a few minutes of work preparing this easy laundry recipe lasts for 256 loads. I have a family of 7 and cloth diaper, so that’s a lot of laundry – but even at 2 loads of laundry per day that still lasts me over 4 months, meaning I only have to worry about making laundry detergent 3x per year. Keep scrolling for the full price breakdown.

I may receive a small commission for items purchased through affiliate links in this post at no additional cost to you.

Why You’ll Love This DIY Detergent Recipe

This recipe doesn’t require any grating or heating a bar of soap since it calls for liquid soap. You just pour all the ingredients into a big jar or bucket, mix, and wait a day or two then it’s ready to go!
Making your own laundry detergent with liquid castile soap and a few simple ingredients is a much cheaper non-toxic alternative to the commercial stuff – it works great and is a good option for those with sensitive skin.
You can make unscented laundry soap or choose a scented liquid castile soap if that’s what you prefer.

HOW MUCH DOES IT COST TO MAKE HOMEMADE LAUNDRY DETERGENT

1 cup of washing soda (sodium carbonate) – $4.78 per box, 7 cups per box, $0.68/cup
1 cup of borax – $5.97 per box, 8.125 cups per box, $0.74/cup
1 cup liquid castile soap – $15.97 per 32oz. (quart) bottle, 4 cups per quart, $3.99/cup

Total cost for one gallon of homemade laundry soap: $5.41

Cost per load at 1/4 cup/load: $0.08/load

?This is a tiny bit more expensive than making DIY laundry detergent by grating up a bar of castile soap and melting it down ($0.02/load) BUT it is still dirt cheap compared to anything on the “natural” side at the grocery store.

What You’ll Need to Make Your Own Detergent

This recipe is for 1 gallon of Liquid Castile Natural Laundry Detergent (I make 4x this recipe in a 5-gallon bucket and it lasts a really long time)

INGREDIENTS

1 cup of washing soda (sodium carbonate)
1 cup of borax
1 cup liquid castile soap
13 cups of water

TOOLS

gallon jar or 5-gallon bucket

large spoon

(optional) liquid laundry soap dispenser jar

(optional) funnel

Step-By-Step Instructions

FOR MAKING ONE GALLON

Heat 6 cups of water to a low boil on the stove.

Add the liquid castile soap, washing soda, and borax to a gallon container Pour the boiling water into the container with the other ingredients and stir until everything is dissolved. Top the container off with 7 cups of water (doesn’t have to be boiling, cold water from the tap is fine) or until it is nearly full. At this point, the laundry detergent will be a clear liquid and yellowish in color.

Place a lid on the container, give it a few good shakes to make sure everything is dissolved, set it aside, and wait 24 hours for it to gel before using. Once gelled, the laundry detergent should be an even consistency and white.

Store as is or in a glass bottle with a dispenser like pictured below. Use 1/4 cup per load of laundry.

FOR MAKING 4X IN A 5-GALLON BUCKET

Heat 24 cups of water (1.5 gallons) to a low boil on the stove.

Add 4 cups liquid castile soap, 4 cups washing soda, and 4 cups borax to a 5-gallon bucket. Pour the boiling water into the bucket with the other ingredients and stir until everything is dissolved. Top the container off with 28 cups (1.75 gallons) of water (doesn’t have to be boiling, cold water from the tap is fine). The bucket will not be totally full, there will be room to dip a big spoon or scoop in and stir without it overflowing. At this point, the laundry detergent will be a clear liquid and yellowish in color.

Store as is or in a glass bottle with a dispenser like pictured below. Use 1/4 cup per load of laundry.

FAQ

IS HOMEMADE LAUNDRY DETERGENT EFFECTIVE?

Homemade laundry detergent can be very effective depending on the recipe and ingredients used. Laundry detergents containing ingredients like soap, borax, baking soda, or washing soda have cleaning properties. However, DIY detergents may not be as potent as commercial detergents that contain specific enzymes and chemicals.

When using DIY laundry detergent, pre-treat stains separately or use additional stain removers if needed. Hard water can also alter the results you’ll get when using DIY laundry detergent – adding a half cup of white vinegar to each load can help with residue from hard water.

CAN HOMEMADE LIQUID LAUNDRY DETERGENT BE USED IN HE (HIGH-EFFICIENCY) WASHING MACHINES?

Homemade liquid detergent can be used in high-efficiency (HE) washing machines as long as it is low-sudsing. Traditional homemade detergent made with fels naptha soap may produce excessive suds, which can cause issues in HE machines, such as poor cleaning performance, longer rinse cycles, or even damage to the machine.

Using a low-sudsing soap option like liquid castile soap solved this problem and works great in HE machines.

IS BORAX TOXIC?

Borax, also known as sodium borate, is a naturally occurring mineral used for various purposes, including in homemade laundry detergent. When used and handled properly, borax is considered to be safe for household use.

Borax is a generally low-in-toxicity, natural product – it can be harmful if ingested or if it comes into contact with the eyes or skin in large amounts. Ingesting high doses of borax can cause GI distress or other health issues.

It’s best to keep borax out of the reach of children and pets and to store it in a secure, labeled container with other cleaning products. When using borax for laundry detergent or any other purpose, follow specific instructions and recommended quantities.

SHOULD I STORE MY HOMEMADE LAUNDRY DETERGENT IN PLASTIC CONTAINERS OR GLASS?

This is really just a matter of preference. The most important thing is that you store your homemade laundry detergent in something airtight. I use a big 5-gallon bucket to store my 4x batch I make a couple times a year, and a smaller container (half-gallon glass dispenser) for use in my laundry room.

If you’re worried about plastic leaching into your detergent, you can use glass to store big batches as well. I have lots of these glass, gallon jars that work great for storing all kinds of things.

CAN I USE BAKING SODA (SODIUM BICARBONATE) INSTEAD OF WASHING SODA?

?You can actually turn baking soda into washing soda through a process called thermal decomposition – which is just a fancy way to say you have to bake it in the oven.

Preheat your oven to 400°F (200°C).
Spread a layer of baking soda on a baking sheet lined with parchment paper or aluminum foil. Use a single layer to allow for even heat distribution.
Place the baking sheet with the baking soda in the preheated oven & bake it for about 1 hour, stirring it every 15 minutes to ensure even heating.
After the hour is up, the baking soda will have transformed into washing soda, which has a duller and more grainy appearance compared to baking soda.
Let the washing soda cool completely before transferring it to an airtight container for storage.

Tips

Wait a couple of days before you use your liquid laundry soap because it will gel over time.
This recipe shouldn’t separate or get too clumpy, but if it does just give the bottle a good shake and it should be good to go.
If you want to scent your laundry detergent, you can add essential oil or herbal infusion. Lavender essential oils are a popular option. Just add a few drops of your favorite essential oils to the container with the castile soap and dry ingredients before adding any water.
If you’re skeptical about the efficacy of homemade detergent, just make a single batch for your first batch. Then, if you like it you can make a big batch.

Storage

If you make a big batch of this laundry detergent, store it in a 5-gallon bucket with an airtight lid or in jars with airtight lids. I like storing a smaller amount in my laundry room in a half-gallon glass jar with a dispenser which takes up less room than a big bucket and is very handy.