Coaster Epoxy Calculator: How Much Resin for a Set
Enter the inside size of your coaster mold, the depth and how many you are making to get the resin to mix and the Part A / Part B split.
Your measurements
Pick your epoxy and the coaster size. Everything updates as you type.
Epoxy
A 1:1 coating epoxy for bar tops, tables and shallow castings, up to 1/4" per coat. Pour coats thicker than 1/4" as 1/4" layers at least 3 hours apart; no sanding needed between coats.
Coasters
Common sets
Pour
Most coasters are 1/4" (6 mm) deep.
Common
10% covers the cup, stirrer and drips. Use 15–20% for live edges, bark and open grain that soak up epoxy.
Results
Total epoxy to mix
mL
= 7.7 fl oz
51 mL per coaster, 4 coasters, plus 10% for the cup. Mix 1:1 by volume, 1.2:1 by weight.
- Part A (resin)
- 113mL
- = 3.8 fl oz
- or 130 g by weight
- Part B (hardener)
- 113mL
- = 3.8 fl oz
- or 108 g by weight
- Batch weight
- 238g
- = 8.4 oz
- At 1.05 g/cm³
- Pours
- 1pour
- Up to 1/4" · 6.4 mm at once
Pour schedule
Pour coats thicker than 1/4" as 1/4" layers at least 3 hours apart; no sanding needed between coats.
| Pour | Fills to | Mix | Part A | Part B |
|---|---|---|---|---|
| 1 | 1/4" · 6.4 mm | 227 mL | 113 mL | 113 mL |
How this was calculated
Area, volume, waste, the split and the layers, with your numbers.
How this was calculated
Area, volume, waste, the split and the layers, with your numbers.
Step 1: Area of the coasters
coasters × π × (diameter ÷ 2)²
= 4 × π × (4″ (101.6 mm) ÷ 2)²
= 50.3 in²Use the inside size of the mold cavity.
Step 2: Volume to fill
area × depth
= 50.3 in² × 0.25″ (6.4 mm)
= 206 mL (7 fl oz)1 cm³ is 1 mL, and 1 US fl oz is 29.57 mL.
Step 3: Add the waste allowance
volume × (1 + waste %)
= 206 mL (7 fl oz) × 1.1
= 227 mL (7.7 fl oz)Covers what stays in the cup and on the stirrer, drips over edges and soaks into wood. Seal-coat bare wood first so it does not drink the flood coat.
Step 4: Split by the volume ratio
Part A = total × 1 ÷ 2, Part B = total × 1 ÷ 2
= 227 mL × 1/2 and × 1/2
= A 113 mL (3.8 fl oz), B 113 mL (3.8 fl oz)TotalBoat TableTop mixes 1:1 by volume. Measure in graduated cups, then mix and transfer to a second cup.
Step 5: Weight of the batch
weight = volume × density; Part A = weight × 1.2 ÷ 2.2
= 227 mL × 1.05 g/cm³
= 238 g: A 130 g, B 108 gBy weight the ratio is 1.2:1, not 1:1, because the resin is denser than the hardener. Weighing is the more accurate way to measure.
Step 6: Layers
layers = ⌈depth ÷ thickest layer⌉
= ⌈0.25″ (6.4 mm) ÷ 0.25″ (6.4 mm)⌉
= 1 pourThe thickest layer is the maker's limit for one pour; thicker pours trap heat and can yellow, crack or ripple.
Sources
TotalBoat TableTop Epoxy: mix ratios, density and thickest pour
Checked against sourceChecked against the maker's documentation. Checked 24 Oct 2026.
- TotalBoat TableTop Epoxy Instruction Sheet and TDS (1A:1B by volume, 1.2A:1B by weight; resin 1.15 and hardener 0.95 g/cm³; max 1/4" per coat; small castings up to 1" deep and 6 fl oz per pour; do not mix more than one gallon at a time.), opened 24 Oct 2026
Average of the resin (1.15 g/cm³) and hardener (0.95 g/cm³) densities at 1:1 by volume. The data sheet also lists a cured density of 1.05 g/cm³.
In short
Epoxy to mix = area × depth + about 10%. 4 round 4"″ coasters 1/4"″ deep need about 227 mL (7.7 fl oz) of TotalBoat TableTop with 10% extra, in one pour.
The maker's limits for small castings decide whether a coaster can be poured at once.
Epoxy mix ratios, density and thickest pour
Figures from each maker's data sheet, checked on the date in the sources. Weight ratios come from the maker; densities are the mixed liquid unless marked.
| Epoxy | Use | Mix ratio | Density (g/cm³) | Thickest pour |
|---|---|---|---|---|
| TotalBoat TableTop Epoxy | Coating | 1:1 by volume, 1.2:1 by weight | 1.05 | 1/4"″ (6.4 mm) |
| ArtResin Epoxy Resin | Coating | 1:1 by volume, 100:84 by weight | 1.051 | 1/8"″ (3.2 mm) |
| EcoPoxy UVPoxy | Coating | 1:1 by volume, 1.2:1 by weight | 1.07 (cured) | 1/8"″ (3.2 mm) |
| TotalBoat ThickSet Epoxy | Deep pour | 1:1 by volume, 1.11:1 by weight | 1.09 | 1/2"″ (12.7 mm) |
| EcoPoxy FlowCast | Deep pour | 2:1 by volume, 2.3:1 by weight | 1.07 (cured) | 1/2"″ (13 mm) to 1 1/2"″ (38 mm) |
| MAS Deep Pour X | Deep pour | 2:1 by volume, 100:43 by weight | 1.0625 | 2"″ (50.8 mm) to 3"″ (76.2 mm) |
Pour limits assume the working temperature on each label. Warmer rooms and larger pours cure hotter, so check your label before pouring.
Worked example: TotalBoat TableTop
Area, then volume, waste, the split between the parts and the pours.
Step 1: Area of the coasters
coasters × π × (diameter ÷ 2)²
= 4 × π × (4″ (101.6 mm) ÷ 2)²
= 50.3 in²Use the inside size of the mold cavity.
Step 2: Volume to fill
area × depth
= 50.3 in² × 0.25″ (6.4 mm)
= 206 mL (7 fl oz)1 cm³ is 1 mL, and 1 US fl oz is 29.57 mL.
Step 3: Add the waste allowance
volume × (1 + waste %)
= 206 mL (7 fl oz) × 1.1
= 227 mL (7.7 fl oz)Covers what stays in the cup and on the stirrer, drips over edges and soaks into wood. Seal-coat bare wood first so it does not drink the flood coat.
Step 4: Split by the volume ratio
Part A = total × 1 ÷ 2, Part B = total × 1 ÷ 2
= 227 mL × 1/2 and × 1/2
= A 113 mL (3.8 fl oz), B 113 mL (3.8 fl oz)TotalBoat TableTop mixes 1:1 by volume. Measure in graduated cups, then mix and transfer to a second cup.
Step 5: Weight of the batch
weight = volume × density; Part A = weight × 1.2 ÷ 2.2
= 227 mL × 1.05 g/cm³
= 238 g: A 130 g, B 108 gBy weight the ratio is 1.2:1, not 1:1, because the resin is denser than the hardener. Weighing is the more accurate way to measure.
Step 6: Layers
layers = ⌈depth ÷ thickest layer⌉
= ⌈0.25″ (6.4 mm) ÷ 0.25″ (6.4 mm)⌉
= 1 pourThe thickest layer is the maker's limit for one pour; thicker pours trap heat and can yellow, crack or ripple.
Epoxy: common questions
Volume, mix ratios, waste and pour depth.
How much resin do I need for one coaster?
Work out one coaster (π × radius² × depth for round, side × side × depth for square), then multiply by the number of coasters. A 4″ round coaster 1/4″ deep holds about 51 mL (1.7 fl oz) before waste. 4 round 4"″ coasters 1/4"″ deep need about 227 mL (7.7 fl oz) of TotalBoat TableTop with 10% extra, in one pour.
Can I pour a coaster in one go?
It depends on the epoxy. TotalBoat TableTop allows 1/4″ per pour, and small castings up to 1″ deep when each pour is under 6 fl oz; ArtResin recommends 1/8″ per coat. Deeper pieces need a deep-pour epoxy or several layers. The calculator checks each coaster against the maker's limits.
Should I measure Part A and Part B by volume or by weight?
Use the basis on the label. Resin and hardener have different densities, so a 1:1 by volume epoxy is not 1:1 by weight: TotalBoat TableTop is 1:1 by volume, 1.2:1 by weight. The calculator gives both, using the part densities from the data sheet.
How much extra epoxy should I mix?
About 10% covers what stays in the cup, on the stirrer and what drips off the edges. Live edges, bark and open-grain wood soak up more, so use 15–20% there, or seal the wood with a thin coat first. The calculator does not model shrinkage; the extra covers it.