How Much Epoxy Do I Need? Epoxy Calculator and Guide

How much epoxy do I need? It is the first question on every resin project, and getting it wrong is expensive either way: buy too little and you are left with a half-filled river and a fresh batch that may not bond cleanly; buy far too much and you have hundreds of pounds of resin slowly ageing on a shelf. The good news is that the maths is simple. Use the epoxy calculator below for a quick answer, then read on for the formula, worked examples and typical costs.

Quick answer: work out the volume of the space you are filling. In metric, litres = length (m) × width (m) × depth (mm), so 1 litre of epoxy covers 1 m² at 1 mm thick. A 1.2 × 0.6 m coffee table top coated 3 mm thick needs about 2.2 litres, before allowing for edges and drips. For river tables, measure only the gap the resin fills. Then add around 10–15% extra for mixing waste and seal coats, and use the calculator below for your own figures.

How much epoxy do I need: the basic formula

Any pour is just a box, or a box with part of it filled with wood. The volume of resin is:

Volume = length × width × depth

Measure all three in the same unit, then convert:

• Metric: 1 litre = 1,000 cm³. So a volume in cubic centimetres divided by 1,000 gives litres.
• Imperial: 1 US gallon = 231 in³. So a volume in cubic inches divided by 231 gives US gallons.
• Converting: 1 US gallon = 3.785 litres, and 1 in³ = 16.39 cm³.

Then adjust for two real-world factors. First, the fill percentage: in a river table, the timber takes up most of the mould, so only the river channel needs resin. Estimate what share of the area is resin, or measure the river at several points and take an average width. Second, a waste allowance of around 10% (15% for flood coats that run off the edges) covers resin left in mixing buckets, drips, small leaks and absorption into the timber.

Remember that epoxy is sold as a combined kit volume. A 15 litre kit means 15 litres once resin and hardener are mixed, not 15 litres of each.

Worked examples

Coffee table top coat

A 120 × 60 cm coffee table needs a 3 mm (0.3 cm) flood coat:

• 120 × 60 × 0.3 = 2,160 cm³ = 2.16 litres
• Add 10%: about 2.4 litres (0.63 US gallons)

If the resin drips over the edges rather than being contained with tape, use 15% instead. A thin seal coat beforehand uses roughly another 0.3–0.5 litres. See our guide to the resin coffee table for build ideas at this size.

River table river

A 200 × 90 cm dining table, 5 cm thick, where the river takes up about 25% of the top:

• 200 × 90 × 5 = 90,000 cm³ = 90 litres for the full mould
• 25% fill: 22.5 litres
• Add 10%: about 24.8 litres (6.5 US gallons)

This is a deep pour, so the resin must be a casting resin rated for the layer depth you plan, poured in two or more layers if needed. Our deep pour epoxy guide explains how to plan those layers, and the river table tutorial covers the full build.

Bar top

An 8 ft × 2 ft bar (96 × 24 in) with a 1/8 in flood coat:

• 96 × 24 × 0.125 = 288 in³
• 288 ÷ 231 = 1.25 US gallons (4.7 litres)
• Add 15% for edge run-off: about 1.43 US gallons (5.4 litres) per coat

Most bars get a seal coat and one or two flood coats, so multiply accordingly. The bar top epoxy guide covers products and technique for this job.

Adding colour: how much pigment and mica?

Pigment does not meaningfully change your volume, but too much can stop the resin curing properly. As a rule of thumb, keep total colourant to a few percent of the mixed weight, and never exceed the maximum on the datasheet (often around 6%). Mica powder is strong: start with roughly a teaspoon per litre for a rich shimmer and add more gradually. Our guide to mica powder for resin goes into ratios and effects.

How much is epoxy resin?

Prices vary by brand, region and kit size, so treat these as typical ranges only:

Larger kits are usually cheaper per litre. Using the river example above, 25 litres of deep pour resin would typically cost somewhere around £500–£1,100, which is often the single largest material cost in the build after the timber.

How much does an epoxy river table cost?

For a DIY build, add up resin, timber, mould materials, abrasives and finish. A small coffee or side table can typically be built for a few hundred pounds in materials; a full dining table with good slabs and 20–30 litres of resin commonly runs from around £1,000 to £2,500 in materials, before tools.

Buying a finished or commissioned table is a different calculation, because it includes many hours of flattening, sanding, finishing and the maker’s experience. Commissioned river and epoxy dining tables typically range from a couple of thousand pounds for smaller pieces to well above that for large tables, premium timber or fibre optic lighting. You can browse finished examples on our epoxy resin tables for sale page.

Tips for accurate measuring

• Measure the inside of the mould, not the timber, and measure depth at several points.
• For irregular rivers, sketch the shape on a grid or split it into rectangles and add them up.
• Order resin from a single batch where possible for consistent colour and clarity.
• Mix in batches you can pour within the working time; see how to pour epoxy resin for technique.

Before you mix a large batch, it is worth reading MIT’s epoxy safety guidance, which covers skin sensitisation, ventilation and safe handling of resin and hardener, whatever size of pour you are planning.

Related guide: Epoxy Wood Filler: Fill Cracks, Knots & Voids

Related guide: How Long Does Epoxy Take to Dry and Fully Cure?

Frequently asked questions

How much epoxy do I need for a table?

For a top coat, multiply length × width × coat thickness; a 3 mm coat on a 120 × 60 cm table is about 2.4 litres with waste. For a river table, multiply the full mould volume by the river percentage and add 10%.

How much epoxy resin do I need per square metre?

Each millimetre of thickness over one square metre needs 1 litre. So a 3 mm flood coat uses about 3 litres per square metre, plus waste.

How much mica powder per gallon of epoxy?

Start with roughly 1–2 tablespoons per US gallon and build up until you like the effect, staying within the manufacturer’s maximum pigment loading.

How much does it cost to make an epoxy table?

Typically a few hundred pounds in materials for a small table and around £1,000–£2,500 for a full-size river dining table, depending heavily on slab quality and resin volume.

Should I buy extra epoxy?

Yes. Allow at least 10% extra, and a little more for first projects, leaky moulds or flood coats running over the edges.

Planning something bigger? Read the resin table guide for the full process, or contact Go Bespoke to discuss a bespoke table built in our London workshop.