How to use the resin volume calculator
- Choose the mold shape and the unit you measured in.
- Enter the length and width, or the diameter for a round mold, and the pour depth.
- Enter the number of molds. Open More options to change the extra for spills or to set the part A and part B mix ratio.
- Read the amount of resin to mix in milliliters and fluid ounces, and how much of each part to measure.
Formula
box mold volume = length x width x depth
round mold volume = pi x (diameter / 2)^2 x depth
1 cubic inch = 16.387064 milliliters
resin to mix = volume x molds x (1 + extra)
Parts A and B are shares of the total by volume. A 2 to 1 ratio means two thirds of the mix is part A.
A 12 by 6 inch tray poured a quarter inch deep
The mold holds 12 x 6 x 0.25 = 18 cubic inches, which is 18 x 16.387064 = 294.97 milliliters, or about 295 ml. With 10% extra the mix is 324.5 ml, or 10.97 fluid ounces. A 1 to 1 ratio gives 162.2 ml of each part, and a 2 to 1 ratio gives 216.3 ml of part A and 108.2 ml of part B.
A round coaster 10 cm across and 0.5 cm deep holds pi x 5 x 5 x 0.5 = 39.27 cubic centimeters, which is 39.3 ml. A box 100 by 50 by 5 millimeters holds exactly 25 ml.
Pouring in layers
Many resins have a maximum depth for one pour, and thick pours can heat up or cloud. If your project is deeper than the maker recommends, split the volume into layers. Enter the depth of one layer and multiply by the number of layers using the number of molds box.
Objects set into the resin, such as flowers or shells, take up space. Pour a little less than the full volume when you embed something large, and top up after.
Safety and related tools
Resin directions about mixing, working time, gloves and ventilation come from the product maker, and they take priority over any amount shown here. For other crafts, try the Clay Shrinkage Calculator or the Bead Strand Calculator. The general Volume Calculator handles other shapes.
Assumptions and limits
- The mold is a plain box or cylinder with straight sides and a flat bottom.
- The mix ratio is by volume. Resins that mix by weight need the maker's weight ratio.
- The extra for spills is an example you can change.
- Embedded objects and curved molds are not modeled.
Frequently asked questions
How much resin do I need for a mold?
Multiply length, width and depth to get the volume, convert it to milliliters, and add a little extra for the cup and stir stick. A 12 by 6 inch mold poured 0.25 inch deep holds about 295 ml.
How do I convert cubic inches to milliliters for resin?
Multiply cubic inches by 16.387064. For example, 18 cubic inches is 294.97 milliliters.
How do I split resin into part A and part B?
Use the ratio on your product label. For a 1 to 1 mix, half of the total is each part, and for 2 to 1, two thirds is part A and one third is part B.
Should I add extra resin?
It is wise, because some resin stays in the mixing cup and on the stirrer. The page starts with 10% as an example. Raise it if your mold is small, since the cup waste matters more.