How the resin calculation works
Resin printers do not use filament by length; they cure liquid by volume. The slicer for your resin printer reports the model volume in milliliters, and supports add more on top. This calculator takes the model volume, adds a support allowance and turns the result into milliliters, grams and cost.
resin ml = model volume × (1 + supports % / 100)weight g = resin ml × densitycost = resin ml / 1000 × price per literprints per liter = 1000 / resin ml
Most standard resins have a density between about 1.05 and 1.20 g/ml. Bottles are usually sold by weight (often 1 kg) but listed as roughly a liter. If your bottle is sold by kilogram, divide by density to get liters, or simply convert the price to per liter.
Measuring the inputs
Model volume
Use the volume the resin slicer shows after hollowing, since a hollowed model uses far less resin than a solid one. If you only have an STL, many slicers and mesh tools report volume. Make sure the units are milliliters, which are the same as cubic centimeters.
Supports
Some slicers report total volume including supports. If yours does, set supports to 0% here. Otherwise pick a percentage: light supports on a compact model may add 10 to 15%, while a miniature with dense supports and a raft can add 30% or more.
Density and price
Check the bottle or data sheet for density. For price, use what you paid per liter including shipping. Engineering resins such as tough, flexible or high-temperature types often cost two to four times standard resin.
Worked example
A hollowed bust has a model volume of 40 ml. You estimate 20% for supports. The resin has a density of 1.10 g/ml and costs $30 per liter.
- Resin used: 40 × 1.20 = 48 ml
- Weight: 48 × 1.10 = 52.8 g
- Cost: 48 / 1000 × 30 = $1.44
- Prints per liter: 1000 / 48 ≈ 20
In practice you will get slightly fewer than 20, because some resin stays on the vat walls, drips off the plate and is lost during washing.
Typical values
| Item | Typical range |
|---|---|
| Standard resin density | 1.05–1.20 g/ml |
| Standard resin price | $20–40 per liter |
| Engineering resin price | $40–150 per liter |
| Support allowance, light | 10–15% |
| Support allowance, miniatures | 20–40% |
| Hollow wall thickness | 1.5–3 mm |
Common mistakes
- Using solid volume for a model you will hollow. A hollowed model can use a third of the resin.
- Double-counting supports. Check whether your slicer's figure already includes them.
- Hollowing without drain holes. Trapped uncured resin can crack the part over time, and it still counts as used resin.
- Forgetting waste. Allow a few percent for resin left in the vat and lost in cleaning, and for failed prints.
Safety
Uncured resin is a skin and eye irritant and can cause sensitization over time. Wear nitrile gloves when handling resin, parts and washing liquid, and wear eye protection when pouring. Work in a ventilated space and keep resin away from food areas. Cure waste resin in sunlight or under UV before disposal, and never pour liquid resin or dirty wash fluid down a drain.
Practical tips
- Hollow larger models and add at least two drain holes near the bottom.
- Orient parts to cut support count where it does not hurt detail.
- Fill several models on one plate. Exposure time depends on layer count, not on how many parts are on the plate.
- Filter resin back into the bottle after printing to reuse it and catch cured flakes.
When pricing resin prints for sale, the resin is often a small share of the real cost. Isopropyl alcohol or other wash fluid, gloves, paper towels, FEP or release film replacement and the time spent removing supports and curing all add up. A common approach is to calculate the resin cost here, then add a fixed amount per print for consumables and a separate charge for labor. Track a few batches to see what your consumables actually cost.