# How to figure how much oil for mold.

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#### scotsman

##### Well-Known Member
I really want to download and try out this spreadsheet. **** my laptop for committing suicide. I really need to get a new one.

#### scotsman

##### Well-Known Member
Thank you for the link. I'll have to wait till I get a new comp though because on my iphone it's read-only

#### Hazel

Thank you, Lee! I'll have to play with this one.

I did find 54 ounces of oil without a water discount almost filled the 5 lb mold. I was a little disappointed because I wanted some to fill a little dragon mold. I used your new calculator and it came up with 61.77 oz. I'll have to try this amount but it won't be until the weekend.

#### Tilia

##### Active Member
I am completely ignorant when it comes to ounces and inches, so I did the math to figure out what it would be in cm and grams.

Take the volume in cubic cm (Length x Width x Height).
Divide that by 2,54^3 (which is 2,54 x 2,54 x 2,54) = 16,39 (to get the cubic cm into cubic inches).
And multiply by 28,35 to convert that into ounces.
Then multiply by the 0,4.

So it's:
(L x W x H) / 16,39 x 28,35 x 0,4

Which is the same as :
(L x W x H) x 0,692

That's for the metric users.

Please note: I have not tested this formula so use at your own risk! Althouth the link given by TopCat http://www.smellychicksonline.com/2008/ ... your-mold/ gives 0,657 for metric users... I don't know where it comes from but it is very close to what I found.
I use metric measurements and everyone seems to agree on something around volume x .7 to calculate the amount of oils needed for a mold. So I tried using that twice now and end up with less soap than needed both times.

I used a tea-box with 2 compartments today with each compartment measuring 8 x 6.5 x 4.5 cm's. So multiplying those measurements by 2 and then by .692 I ended up with 323 grams of oils needed. While these molds are small I still ended up with the soap being over half a centimeter below the line I wanted it to reach.

For the recipe I used the standard water amount used in soapcalc of 38%. I that what makes a difference? Not sure on how to factor the water amount in the calculation.

#### IrishLass

Staff member
Yep- the water amount (and any other extra additives included) will have an effect on the level. I don't exactly know how to calculate those variables in, though. I just use the equation as a rough guide and then keep meticulous notes of the actual outcomes and adjust from there.

IrishLass

#### Cactuslily

##### Well-Known Member
Idk why I'm still struggling so much! I seem to have a mental block when figuring out what size mold to use for what recipe. For example I made a batch of soap using BB 10" mold. Per calculations, I got 38.5oz. It states on website it holds 50. I'm assuming the recipe given could have had more soap added to mold so that's the differance. If a recipe states it makes a2 lb batch, does that mean I can use my 2.5 mold? Why am I having such a hard time?! I'm feeling my age! Am I overcomplicating this? L x W x H x .40= ounces of oils needed. This doesn't account for water and additives, correct? I plugged in 50ounces to soap calc ( which is what BB states). My recipe came out with a total of 53.1 ounces not including FO. The original recipe held total of 43.8 ounces. Does that mean my recipe won't fit into a 50 mold? Am I even making sense? Uggh! Probably not.

#### Saponista

##### Well-Known Member
LxWxHx0.4 is the calculation you would use if you were using full water. So you would do that and the resulting value is the amount of oils you would put into soapcalc with full water to fill your mould. Any other additives on top of that will increase the volume further and overfill the mould. If you are using a water discount then you need to do a different calculation. If you put the amount of fragrance you want to use into soapcalc too, it will take it into account for you I think.

#### TrishNZ

##### Well-Known Member
Has anyone worked this out in metric?

#### Kittish

##### Enthusiastic Newbie
Has anyone worked this out in metric?
Post #187 has the weight/volume ratios for water, oils, and solid fats given in both metric and imperial. It's kind of clunky to get there, but with that info, plus the measurements of your mold you should be able to come up with a fairly close answer.

Also, this is an old thread. Last post before ours were over two years ago (though I'll admit the info in the thread may well be handy to several of us new folks). Necro posting is kind of frowned on, overall. Much better to quote snips from the old thread you're referencing in a new thread.

#### TrishNZ

##### Well-Known Member
Post #187 has the weight/volume ratios for water, oils, and solid fats given in both metric and imperial. It's kind of clunky to get there, but with that info, plus the measurements of your mold you should be able to come up with a fairly close answer.

Also, this is an old thread. Last post before ours were over two years ago (though I'll admit the info in the thread may well be handy to several of us new folks). Necro posting is kind of frowned on, overall. Much better to quote snips from the old thread you're referencing in a new thread.
Sorry I am new and just using the search feature. I am not sure what Necro posting is.

#### Steve85569

Supporting Member
L x W x H = volume

Trish,

If you calculate in metric (cm) then multiply volume by 0.70 for the weight of oils that will fit.
If you calculate in inches use 0.37 for the weight of oils.

Some corrections will need to happen because of additives but this get me real close.

##### Well-Known Member
I realize this thread was started in 2008 but I'm hoping that someone can answer my question. I've seen this formula but with different numbers such as .40, .38 & the last post suggested .37. I don't care which number I use, I can't seem to get the right amount. When I've tried for example 7 * 3.75 * 3.5 * .40= 36.75 ounces (rounded up to 37) as the amount of oils, I end up with a few ounces of too much soap. So, reasoning that the formula calculates volume/how much the mold holds, I've tried creating recipes that have a total weight of 37 oz but I usually end up a few ounces shy of a full mold. Where am I going wrong?

#### dibbles

##### Supporting Member
Supporting Member
Are you using a water discount? Using that formula, with full water, 31 ounces will fill my mold. At 30% lye concentration, 32 ounces will fill it, with maybe a bitty bit left over.

##### Well-Known Member
I usually use full water, 38% and whatever lye concentration that soapcalc gives me. I made this mold & 1 other about 2 years ago & I don't think I've ever been able to correctly calculate how much soap batter I need.

#### soaperwoman

##### Active Member
I know this may sound dumb but I hate math so all I do is fill my mold with water and then measure that to get my volume. Then I reverse engineer the water amount on a soap calc and oila! It isn't very scientific but it works every time.

##### Well-Known Member
I know this may sound dumb but I hate math so all I do is fill my mold with water and then measure that to get my volume. Then I reverse engineer the water amount on a soap calc and oila! It isn't very scientific but it works every time.
I've done that with my silicone molds but this is a homemade wooden mold. It's not going to hold water.

#### dibbles

##### Supporting Member
Supporting Member
Why don't you purposely make a little too much batter with your regular recipe/water amount and weigh what is left when your mold is full?

#### Millie

##### Well-Known Member
I've done that with my silicone molds but this is a homemade wooden mold. It's not going to hold water.
If you are having good luck using that method, could you line your mold with a garbage bag for your water measurement?