Easy Epoxy Calc

How much resin for a 30 × 40 canvas?

Short answer

A 30 × 40 in canvas (8.3 square feet) needs about 91.4 fluid ounces of mixed resin for a full 1/8 inch coat, including 10% extra — about 0.71 gallons, mixed as 2 batches of roughly 45.7 fluid ounces.

How to work it out

  1. Area: 40 in × 30 in = 1,200 sq in
  2. 1,200 sq in × 1/8 in = 150 cu in = 83.1 fl oz; + 10% = 91.4 fl oz (≈ 100 oz on a scale)
  3. 91.4 fl oz ÷ 48 fl oz per batch = 2 batches of about 45.7 fl oz
  4. Mix ratio 1 : 1 by volume, SG A 1.15 / B 0.95 (typical, not published by the maker — type your data sheet’s SGs for exact weights) → Part A 45.7 fl oz (54.8 oz) + Part B 45.7 fl oz (45.3 oz)

A 30 × 40 is large enough that you’ll be racing the resin’s working time — the minutes after mixing when it still flows and self-levels. The trick is to never have all of it in one cup: split it into batches, pour one, and mix the next while you spread.

Adjust for your project

in
in
Most resin boxes’ coverage claims assume a thin coat — pick 1/16 in to match the box. 1/8 in is a full, glassy, self-levelled coat and uses about twice as much.
fl oz
Total of both bottles together, e.g. a 32 oz kit = 16 oz + 16 oz.
More options: waste · ratio · SG A …
%
Cup residue and drips
Only changes the Part A / Part B split — it’s printed on the kit. Tabletop and art resins are usually 1:1; deep pour often 2:1.
From the TDS, in g/ml. Leave blank for 1.15 (typical, not published by the maker).
From the TDS, in g/ml. Leave blank for 0.95 on 1:1 kits or 0.97 on other ratios (typical, not published by the maker).
fl oz
Your own limit per cup or bucket. Go smaller if your resin has a short working time.
Art resin to buy91.4 fl oz2,704 ml
Whole batch by weight, incl. waste (kitchen scale)
100 oz (2,839 g)
Kits to buy
3 kits
Mixing batches
2 batches
When mixing — Part A (resin)
45.7 fl oz (1,352 ml)
When mixing — Part B (hardener)
45.7 fl oz (1,352 ml)
Part A by weight
54.8 oz (1,555 g)
Part B by weight
45.3 oz (1,284 g)
Left over from the last kit
4.57 fl oz (135 ml)
  • What to buy: 3 × 32 fl oz art resin kits. Each kit has both bottles (resin + hardener) — you don’t buy them separately. Looking at a different kit size? Change Kit size above.
  • Mix it in 2 batches of about 45.7 fl oz — pour the first, then mix the next while you spread — so no cup sits long enough to heat up and start to thicken.
  • fl oz = measured in a cup; oz = weighed on a scale. Use whichever your resin label gives.

For this job · affiliate link
Clear art resin kitYou need 91.4 fl oz, so 3 × 32 fl oz kits — or price one bigger kit, which is often cheaper per ounce. A 1:1 art resin self-levels over a painting without needing a scale.
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Mixing batches by batch size (30 × 40 at 1/8 in)

Mixing batches by batch size (30 × 40 at 1/8 in)
Largest batchMixing batches
Up to 32 fl oz3 batches
Up to 48 fl oz2 batches
Up to 64 fl oz2 batches

What to know about a 30 × 40 canvas

Batches first. At the default 48 fl oz limit this canvas takes two batches of about 45.7 fl oz — roughly 23 fl oz of each part per batch. A workable rhythm: mix batch one, pour it in a zigzag over the first half, and start mixing batch two while a helper spreads. Pour batch two on the other half and blend the seam with the spreader while both are still wet. If your resin has a short working time, drop the limit to 32 fl oz and you get three batches of about 30.5 fl oz instead.

Kits: three 32 fl oz kits hold 96 fl oz, which leaves only about 4.6 fl oz over — no room for a spill. A 1 gallon kit leaves about 36.6 fl oz, enough to coat the edges or a smaller piece.

The common mistake at this size is pouring everything in the middle and waiting for it to level out. Across 40 inches the resin thickens before it reaches the corners; spread it to the edges yourself, then let it level. Warm the room first rather than the resin: ArtResin recommends 75–85°F, and a cold room makes a big coat stiff and slow to spread, while warmed resin in a big cup sets off faster.

For the size below, see how much resin for a 24x36 canvas; for the next size up, with the sides coated, how much resin for a 36x48 canvas.

Different size? Use the full Resin Art Calculator.

What you’ll need

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Frequently asked questions

How much resin for a 30x40 canvas at 1/16 inch?

About 45.7 fluid ounces with 10% extra — 1 batch at a 48 fl oz limit, and 2 kits of 32 fl oz.

How much resin for a 30x40 canvas with the sides coated?

About 107 fluid ounces with 1 1/2 inch sides and 10% extra — 3 batches at a 48 fl oz limit.

Other common sizes

Sources