Embedment Calculator
Calculate the net resin needed after accounting for the volume displaced by embedded objects like flowers, coins, or wood pieces.
About this calculator
This calculator solves the volume-subtraction problem specific to embedment casting: the resin you pour only needs to fill the space the mold doesn't already occupy with your embedded objects. It takes the mold's interior volume in cubic inches, subtracts the objects' total volume (never letting the result go negative), and converts that net figure to fluid ounces using the standard 0.554 oz-per-cubic-inch conversion for resin. A separate weight estimate multiplies the net volume by your resin's density (grams per cm³, converting cubic inches to cm³ at 16.387 cm³/in³) so you can measure by scale rather than volume, which matters because most resin systems are formulated to be mixed by weight for accuracy.
The headline output adds a flat 10% overage on top of the exact net figure, covering the reality that some resin clings to mixing cups and stir sticks rather than making it into the mold. The displacement percentage — objects' volume divided by mold volume — flags two edge cases worth knowing before you pour: above 50%, the objects occupy so much of the cavity that resin may struggle to flow completely around every surface, risking trapped air pockets or dry spots; below 10%, you're essentially doing a plain resin pour with minor inclusions. The most common estimation error here isn't the math but the input — figuring an irregular object's true volume by eye tends to run low, so water-displacement measurement (submerging the object and reading the volume change) is far more reliable than approximating it as a simple shape.
Inputs
Results
Resin Needed (with 10% overage)
45.71 oz
≈ 11 sticks of butter
How to Use This Calculator
- Enter the total volume of your mold cavity in cubic inches (length × width × depth for a rectangular mold).
- Measure or estimate the total volume of the objects you are embedding and enter that in cubic inches.
- Enter the resin density in g/cm³ from your product datasheet (most epoxies are 1.0–1.2 g/cm³).
- Read the net resin needed in ounces (with 10% overage) — this accounts for the space the objects displace.
- Use the exact resin oz and gram weight to measure your resin and hardener precisely before mixing.
How the result changes with Mold Volume
| Mold Volume | Resin Needed (with 10% overage) |
|---|---|
| 50 | 15.24 oz |
| 75 | 30.47 oz |
| 150 | 76.18 oz |
| 250 | 137.12 oz |
What each input means
- Mold Volume
- Total interior volume of the mold in cubic inches. For a rectangular mold: length x width x depth.
- Embedded Objects Volume
- Total volume of all objects being embedded. Estimate by water displacement or by approximating each object as a simple shape.
- Resin Density
- Density of your mixed resin. Most epoxies are 1.05-1.15 g/cm³. Check your product data sheet for exact value.
How this is calculated
Worked example, using the default values
- Identify Input ParametersMold Volume = 100, Embedded Objects Volume = 25, Resin Density = 1.1 = 3 input(s) provided
- Calculate Resin NeededResin Needed45.71 = 45.71
- Calculate Net ResinNet Resin41.55 = 41.55
- Calculate Resin WeightResin Weight1351.9 = 1351.9
Engine last updated . Checked against 1 independently-derived test — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why does the calculator subtract the objects' volume instead of just calculating the full mold volume?
Every cubic inch your embedded objects occupy is a cubic inch of space resin won't need to fill, so using the full mold volume would overestimate how much resin to mix. The calculator computes moldVolumeCuIn minus objectsVolumeCuIn (never letting the result go below zero) to get the actual net resin volume needed.
Why does the resin weight output ask for density separately from the volume figures?
Volume and weight aren't interchangeable for resin because density varies by product — the calculator converts your net volume to cm³ (16.387 cm³ per cubic inch) and multiplies by the density you enter to get grams. Because most resin systems specify their mix ratio by weight rather than volume for accuracy, this weight figure is what you'd actually use on a kitchen or gram scale.
What does the displacement percentage warning actually change about how I should pour?
Displacement percentage is simply objects' volume divided by mold volume. Above 50%, the calculator warns that resin may not be able to flow completely around every surface of your embedded objects, which risks trapped air pockets or dry spots — you may need to pour more slowly or in stages. Below 10%, it's flagging that you're essentially doing a plain resin pour with only minor inclusions, so precision on the objects' volume matters less.
Why is the 10% overage applied only after the objects' volume is subtracted?
The overage exists to cover resin lost to mixing cups and stir sticks during pouring, which is a fixed loss tied to how much resin you're actually working with — not to the mold's total capacity. Applying it to the net (post-subtraction) figure keeps the overage proportional to the real pour volume rather than inflating it based on space the objects already occupy.
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