1:1 epoxy by weight: how many grams of each part?
A 500 ml batch of 1:1-by-volume epoxy is about 288 grams of resin and 238 grams of hardener at typical densities (1.15 and 0.95) — roughly 100 : 83 by weight, not 1:1. By volume it’s still 250 ml of each part.
How to work it out
- 1 : 1 by volume → by weight 1 × 1.15 : 1 × 0.95 = 100 : 83 (your SGs)
- Batch 500 ml (525 g) → A 288 g (250 ml) + B 238 g (250 ml)
Most art and tabletop resins are sold as 1:1 by volume, and it’s tempting to weigh them 1:1 on a kitchen scale. With typical densities that puts in about a fifth more hardener by volume than intended. Real labels bear this out: TotalBoat lists its TableTop epoxy as 1:1 by volume and 1.2 : 1 by weight, almost exactly the 1.21 : 1 the calculator works out here.
Adjust for your project
- Part A by weight
- 288 g
- Part B by weight
- 238 g
- Part A by volume
- 250 ml (8.45 fl oz)
- Part B by volume
- 250 ml (8.45 fl oz)
- Ratio by weight
- 100 : 83 (1.21 : 1)
- Ratio by volume
- 100 : 100 (1 : 1)
- Total batch weight
- 525 g
- Total batch volume
- 500 ml (16.9 fl oz)
- Specific gravities vary by product. Use the values on your epoxy’s technical data sheet — or the weight ratio it lists, which is the most reliable figure.
500 ml of 1:1 epoxy: grams by resin density
| Part A specific gravity | Part A by weight | Part B by weight | Ratio by weight |
|---|---|---|---|
| Resin SG 1.05 | 263 g | 238 g | 100 : 90 (1.11 : 1) |
| Resin SG 1.1 | 275 g | 238 g | 100 : 86 (1.16 : 1) |
| Resin SG 1.15 | 288 g | 238 g | 100 : 83 (1.21 : 1) |
| Resin SG 1.2 | 300 g | 238 g | 100 : 79 (1.26 : 1) |
What to know about weighing a 1:1 epoxy in grams
- If the label gives a weight ratio, use it. Pick TotalBoat TableTop in the product list, or switch Label ratio is by to weight and type 1.2 and 1. The grams then come straight from the label — 300 g and 250 g for this batch — and the densities only affect the volume columns.
- Tare the cup between parts. Put the empty cup on the scale, zero it, pour resin to the first number, zero again, then pour hardener to the second. Pour the last few grams slowly; overshooting a 1:1 system is easy because both parts look alike.
- Overshot the resin? Match it, don’t guess. Set Start from to Part A already measured and type what the scale shows — 300 g of resin at these densities needs about 248 g of hardener, not 238.
- Half a liter is a typical art batch. It’s roughly what a medium canvas, a set of coasters or a small tray takes. Past a liter or so in one cup, the heat of the reaction shortens your working time — two smaller batches are easier to control than one big one.
- Why a fifth matters. Too much hardener doesn’t make the resin cure harder or faster; Epoxyworks notes it leaves a mix that can never fully cure. On art resin that usually shows up as a soft, slightly tacky surface that dents under a fingernail days later.
Deep-pour and laminating systems are often 2:1 — see 2:1 epoxy by weight for that version. For the weight of a full kit rather than a batch, see how much a gallon of epoxy weighs.
Different size? Use the full Epoxy Mix Ratio Calculator.
What you’ll need
- Digital scale (0.1 g)Budget price
For mixing by weight. Far more accurate than cup lines for small batches — and it doubles for the water method on molds.
See options on Amazon (opens in a new tab) - Graduated mixing cups & stir sticksBudget price
Small cups marked in ounces and ml for art, coasters and tumblers. Use a fresh cup when you transfer to a second container.
See options on Amazon (opens in a new tab) - Nitrile glovesBudget price
Keep uncured resin off your skin. Repeated skin contact is how many people become sensitized to epoxy.
See options on Amazon (opens in a new tab)
As an Amazon Associate we earn from qualifying purchases. Links to products are affiliate links — they cost you nothing extra and help keep these calculators free.
Frequently asked questions
How many grams of each part for 250 ml of 1:1 epoxy?
About 144 grams of resin and 119 grams of hardener — 125 ml of each by volume.
How do I split a 1 kg batch of 1:1 epoxy by weight?
Weigh about 548 grams of resin and 452 grams of hardener. That’s 952 ml of mixed epoxy.
What happens if I weigh a 1:1-by-volume epoxy 1:1 by weight?
For a 500 ml batch you’d pour about 226 ml of resin and 274 ml of hardener by volume — about a fifth too much hardener, which can leave the cure soft or tacky.
How many grams is 500 ml of TotalBoat TableTop?
About 300 grams of Part A and 250 grams of Part B — TotalBoat’s 1.2 : 1 weight ratio, 250 ml of each by volume.
I weighed 300 g of 1:1 resin — how much hardener?
About 248 grams of hardener at typical densities (1.15 and 0.95) — 522 ml of mixed epoxy.
Other common sizes
- 2:1 epoxy by weight — 12.8 oz (363 g) Part A + 5.4 oz (153 g) Part B
Sources
- MAS Epoxies — Deep Pour X product page (opens in a new tab) — 2:1 mix; poured 2–3 in thick per pour (2 in minimum — thinner pours cure slowly); about 12 h working time and a 36 h cure; 1.5, 3 and 6 gallon kits; keep materials and shop at 60–80°F; seal-coat bare wood first. No specific gravities or weight ratio listed.
- EcoPoxy — FlowCast product page (opens in a new tab) — 2:1 by volume, 2.3:1 by mass; 13–38 mm (0.5–1.5 in) per layer for pours up to 30 L; pour the next layer while the last is tacky; demold after 3 days; 6, 12, 30 and 60 L kits.
- EcoPoxy — FlowCast technical data sheet (PDF, June 2022) (opens in a new tab) — Specific gravity Part A 1.122, Part B 0.978 at 22°C; tacky-to-touch (next-layer window) 20–44 h and demold 3 days for a 72 × 8 × 1.5 in casting at 21°C.
- TotalBoat — TableTop Epoxy product page (opens in a new tab) — 1:1 by volume, 1.2:1 by weight; up to 1/4 in per coat; 2 qt, 1, 2 and 4 gal kits (A + B together); 40 min working time and at least 3 h before recoating at 70°F; full cure 5–7 days.
- WEST SYSTEM — 105 Resin / 205 Fast Hardener technical data sheet (PDF) (opens in a new tab) — 5 parts resin : 1 part hardener by volume = 5.19 : 1 by weight (acceptable 4.83–6.20 : 1); pot life 9–12 min (100 g at 72°F); cured SG 1.18.
- Epoxyworks (WEST SYSTEM): The Basics of WEST SYSTEM Epoxy Resin and Hardener (opens in a new tab) — Altering the amount of hardener does not change cure speed; it leaves a mixture that can never fully cure