Resin Calc

Epoxy Calculator

A free resin calculator for any pour. Enter your project size and mix ratio to get the total volume, Part A and Part B instantly, in imperial or metric.

  • Free, no sign-up
  • Imperial and metric
  • Volume or weight

Epoxy Volume Calculator

Quick start
Project Shape
Dimensions
in
in
in

Your Results

Total Epoxy Needed

131.7fl oz

APart A (Resin)

65.83fl oz

BPart B (Hardener)

65.83fl oz

Equivalent by weight
75.54 / 65.24 oz
Cavity volume
216 in³
Mix Ratio (Resin : Hardener)
1:1

Recommended for this pour

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Deep Pour Casting Resin

Low-exotherm formula for thick single pours, commonly 2 to 4 inches per layer though some products allow less, so check your data sheet. The right choice for river tables and thick castings. Usually 2:1, though 3:1 systems exist.

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Essential mixing tools

Building a river table?

A river table is three pours, not one

Most calculators give you one number for the whole table. That is why people run short. The channel needs a low-exotherm casting resin, usually 2:1, while the seal and flood coats need a coating epoxy at a different ratio. They are two products, bought separately.

This calculator is the only one we know of that splits them for you.

Open the river table calculator
  1. 1

    Seal coatCoating epoxy

    Stops the raw wood outgassing bubbles into the pour

  2. 2

    Deep pourCasting resin

    Fills the channel, layered if it exceeds your product depth

  3. 3

    Flood coatCoating epoxy

    Final coat across the whole slab, not just the river

How Much Epoxy Do I Need? How to Calculate Resin Volume

Working out epoxy volume comes down to three steps: measure the cavity, convert cubic measurements to liquid volume, then split that volume by your mix ratio. This calculator does all three, but here is the math so you can check it by hand.

  1. 1

    Step 1: Measure the cavity

    For a rectangular pour such as a river table channel, multiply Length x Width x Average Depth. For a round mold or coaster, use pi x (Diameter / 2)^2 x Depth. Measure the deepest and shallowest points and average them for an irregular channel.

  2. 2

    Step 2: Convert to liquid volume

    One cubic inch equals 0.554 US fluid ounces, and one cubic centimetre equals one millilitre. A 12 x 12 x 1 inch pour is 144 cubic inches, or roughly 80 fl oz of mixed epoxy.

  3. 3

    Step 3: Split by mix ratio

    For a 2:1 epoxy, divide the total by 3: two parts are resin (Part A) and one part is hardener (Part B). Always measure by volume unless your product specifies mixing by weight, in which case the epoxy weight to volume calculator will convert it for you.

  4. 4

    Step 4: Add a waste allowance

    Resin clings to cups and stir sticks and you will always lose a little. Mixing 5-10% extra prevents running short mid-pour, which can leave visible seams.

Calculating resin for a river table

River tables are the most common deep pour project. Measure the length of the channel, then take the width at several points and average them since live-edge slabs are rarely straight. Depth is your slab thickness. The river table epoxy calculator handles all three pours at once. Because river channels usually exceed 1.5 inches, use a deep pour epoxy and set this calculator to the 2:1 or 3:1 ratio your product specifies.

Epoxy Resin Mix Ratio Calculator: How 1:1, 2:1 and 3:1 Work

The mix ratio is the volume of resin (Part A) to hardener (Part B). It is set by the chemistry of the product and is not adjustable. A wrong ratio leads to soft, sticky or cloudy epoxy.

1:1 Table top and coating epoxy

Equal parts resin and hardener. Fast-curing, thick and self-levelling. Ideal for bar tops, art, and coats up to about 1/8 inch per layer. Generates a lot of heat, so it is not suitable for deep casting.

2:1 Deep pour and casting epoxy

Two parts resin to one part hardener. Slower cure with a lower exotherm, allowing single pours of 2 to 4 inches. This is the standard for river tables and large castings, and the deep pour epoxy calculator is set up for it.

3:1 and 4:1 Specialty and marine epoxies

Common in laminating, boat-building and some deep casting systems. These require precise measurement because a small error in the hardener has a big effect on the cure.

Frequently Asked Questions

How much epoxy do I need for a 12x12 inch surface?

For a 1/8 inch coating over 12 x 12 inches you need about 10 fl oz of mixed epoxy. At a 1 inch depth the same area needs roughly 80 fl oz (about 2.4 litres). For thin coats measured by area, the epoxy coverage calculator is quicker. Use the calculator above for your exact depth.

Does the calculator measure by volume or by weight?

Both. The default is by volume (fluid ounces or millilitres), which is how most consumer epoxies are labelled. Switch "Measure by" to Weight if your product gives the ratio by weight. Enter the specific gravity of each part from the technical data sheet and the tool converts the cavity volume into grams or ounces of resin and hardener.

What is the maximum depth for table top epoxy?

Most 1:1 coating epoxies are limited to 1/8 to 1/4 inch per pour. Anything over 2 inches in a single pour needs a dedicated deep pour epoxy formulated to release heat slowly.

Why do I need extra epoxy beyond the calculated amount?

Some epoxy is always left behind in mixing cups and on stir sticks, and wood absorbs a small amount. Adding 5-10% extra ensures you can complete the pour in one go.

Can I pour epoxy in layers instead of using deep pour resin?

Yes. Pour coating epoxy in layers within its maximum thickness and let each layer reach a tacky cure before adding the next. Deep pour epoxy is simpler for thick sections because it avoids layer lines.