# How much to cut the base?? How can you know?

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#### sheilaohga

##### Active Member
Hi, I am not so used to M&P and want to know how much I would need to cut for my mold.
I have several silicone molds I want to use for my M&P but they are all different in sizes and shapes.
I don't want to cut up too many pieces and let them be wasted, or I don't want to have shortage in order to not fill the molds.

How do you know/calculate how much base to cut for that specific mold?
The mold only shows the dimension and not how much it can hold.

I poured water to see how much it can hold and one cavity holds 3.4 oz.
If I times that by the number of cavity, will that work?
e.g) 3.4 x 6 cavities = 20.4 oz
Do I cut up 20.4 oz of the base (or maybe a little more to be safe)?

Thank you.

#### Viore

##### Well-Known Member
The easiest method I've found for calculating how much a mold holds is to weigh the empty mold, fill it with water (like you did), and then weigh the full mold to find out the weight of water used. then when cutting your M&P soap blocks, cut enough to equal the weight of the full mold.

So if your empty mold weighs 10 oz and your full mold weighs 30 oz, then you need to cut off 20 oz of base to fill that mold.

#### dixiedragon

##### Well-Known Member
I would email the company and ask them for a weight to volume (or vice versa) conversion. If you can figure out how much 1 cubic inch (for example) of base weighs, then you can figure out how much weight will fill the volume of your mold.

##### Member
I have used the water weighing method above, but I still don't come out exact. If I really only wanted to scent and color the EXACT right amount of base, I think I would use the water method to get an approximate amount, then melt that much base and pour it and let it cool, then measure what I actually used (unmold it!), and then re-melt and make my soap. Most important? Write it down so you only have to figure it out once!

I hate having just a little bit left over. . . feel like I am wasting and don't know what to do with it.

#### BattleGnome

##### Well-Known Member
I hate having just a little bit left over. . . feel like I am wasting and don't know what to do with it.
I have silicone ice cube molds that I pour the remainder into. It's either a contained shape for next time, a cute embed, or a 2-3 use soap for by the sink.

#### dixiedragon

##### Well-Known Member
I have a similar issue with my lip balm - I hate having just a little left! So I have a small glass container that I pour those little drips into, then when I have enough I will pour them into a tube for my personal use.