One of the questions I get most is how much melt and pour soap to melt for a mold. Here’s the simple way I’ve measured my molds for years: a kitchen scale and some water. It’s not exact, but it comes very close and keeps you from wasting soap.
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What You Need
- A kitchen scale
- Water and a pour cup
- Your molds, like a square loaf mold, a 6 cavity mold or a small ball mold
- A soft spatula for molds with lots of little cavities
- A Sharpie to label your molds
How to Measure a Soap Mold
1. Zero the Scale
Set your scale on the counter and zero it. Have your water and pour cups ready.
2. Put the Mold on the Scale and Zero It Again
Set the empty mold on the scale, then zero the scale again so you’re only weighing what goes in.
3. Fill with Water
Pour water into the mold until it’s as full as you’d fill it with soap. My square mold read about 20.7 oz, so I call it 21 oz.
4. Label the Mold
Empty the water, dry the mold, and write the amount on the back with a Sharpie. It eventually washes off, so you can rewrite it as needed.
5. Cavity Molds
For a cavity mold, just measure one cavity. One cavity in my pink 6 cavity mold holds about 3½ oz, so the whole mold takes about 21 oz.
6. Molds with Lots of Little Cavities
Molds like a small ball mold are a little messier. Pour water across the mold, then run a soft spatula over it to fill all the little holes. Mine holds about 3.1 oz.
7. Column Molds
Column molds are measured the same way. Or fill the column with water and pour it into a container sitting on the scale.
Tips
- It’s an estimate. Melted soap weighs a little differently than water, so you may need a bit more or less.
- Round to make it easy. 20.7 oz becomes 21 oz.
- Less is better than too much. I’d rather run a little short than have lots of leftover soap. Keep a small extra mold nearby for leftovers.
- Label everything. Writing the amount on each mold saves time on every batch.
- Use the number for fragrance. Once you know your mold size, it’s easy to work out fragrance: up to 5 ml per 16 oz (1 lb) of soap base, and never more.
FAQ
Does soap weigh the same as water?
Not exactly, but it’s close enough to plan a batch.
What if I have soap left over?
Pour it into a small spare mold or embed mold and save it for another project.
More Beginner Guides
- Melt and Pour Soap Recipes
- How to Swirl Melt and Pour Soap
- How to Package Melt and Pour Soap
- Which Clear Melt and Pour Soap Base Is Clearest?
- All my melt and pour soap tutorials on YouTube
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