Tabletop epoxy calculator

The calculator works out what runs off the edges from the length of the edge. New to the words? See epoxy words explained. Refinishing an old table? Sand the old finish dull and clean it well first; if you sand back to bare wood, add a seal coat.

Flood coat vs seal coat

A seal coat is a thin layer brushed or scraped on first to close the wood’s pores so air doesn’t bubble up into the finish. A flood coat is the thicker, self-leveling layer that gives the glass look. Most tabletop epoxies level at about 1/8 in (3 mm) — TotalBoat, for example, rates its TableTop epoxy at 12.8 sq ft per mixed gallon at 1/8 in, up to 1/4 in per layer, and says to seal-coat wood and other porous surfaces first. If you want more build than that, pour a second coat inside the recoat window rather than one heavy pour.

top = area × thickness × coats
drips = edge length × 1.25 fl oz per ft (121 ml/m) × (thickness ÷ 1/8 in) × coats
side film = edge length × edge thickness × 1/32 in × coats
clear coats = (top + drips + side film) × (1 + 5% bucket/other)
seal coat = (area + edge length × edge thickness) × seal rate × 1.05
round: area = π × (diameter ÷ 2)², edge = π × diameter
1 US gallon = 231 cu in → covers ≈ 12.8 sq ft at 1/8 in; 1 liter covers ≈ 0.33 m² at 3 mm

For a 60 × 30 in desk: 60 × 30 × 0.125 = 225 cubic inches, or 0.97 gallons on the top. The edge is 15 ft all the way round, so about 18.8 fl oz runs off it and another 4.68 fl oz stays on the 1.5 in sides. Add 5% for the bucket and it comes to 1.21 gallons — a 1-gallon kit would leave you short, so buy two, or one larger kit. The How much epoxy for a 60 x 30 desk page adds the seal coat for bare wood.

Art-resin coverage figures can look far more generous: ArtResin, for instance, works on about 4 oz of mixed resin per square foot of artwork. A true 1/8 in layer over one square foot is 18 cubic inches — about 10 fluid ounces — and a table loses more again off its edges, so plan a flood coat by volume, as this calculator does, and use any per-kit coverage claim as a cross-check rather than the plan.

Why drips are worked out from the edge

What runs off a table depends on how much edge it has, not how big the top is. The calculator allows about 1.25 fl oz per foot of edge for each 1/8 in coat (121 ml per metre), scaled for thicker or thinner coats, plus a 1/32 in film left on the sides. A flat percentage gets this wrong both ways: it starves small tops and overbuys for big ones. On a 12 in round, the drips and side film are about 4.9 fl oz of a 13.4 fl oz total; on a 4 × 8 ft top they are about 0.29 gallons of 2.93. The 5% on top covers what stays in the bucket and on the spreader.

Taping a dam around the top instead (the Edges option) stops the drips, but the sides stay bare. A round top uses π × diameter for its edge; an oval uses Ramanujan’s close approximation of the perimeter.

How much the seal coat takes

Seal coats are meant to be thin — many people scrape them on so little is left on the surface. As a rule of thumb, a seal coat ≈ 1–2 fl oz per sq ft (0.3–0.6 L/m²), more on spalted or end grain. Pick the line that matches your wood: about 1 fl oz/sq ft for closed-grain or already-flat wood, 2 for open grain such as oak, ash or walnut, and 4 for spalted, burl, end grain or punky wood, which often needs a second coat. The seal coat covers the sides too, gets 5% for the cup and brush, and is mixed as its own small batch.

Live-edge slabs

A live-edge slab isn’t a rectangle, so one width misleads. Choose Live-edge slab, measure the length, then measure across the face at three to five evenly spaced spots. The calculator uses the average width for the area and 2 × (length + average width) for the edge. The wavy edge is a little longer than that, but the difference is small next to the drip allowance. Fill cracks and knots with a deep-pour or gap-filling epoxy first — they aren’t in this figure.

Batches, mix ratio and brands

Under More options, the largest batch you’ll mix (1 gallon or 4 liters by default) turns the total into batches per coat, each with Part A and Part B by volume and by weight. Choosing TotalBoat TableTop fills in its 1:1 ratio and weights from the maker’s page; for any other kit, set the ratio from its label.

Worked examples for common table sizes

• Rectangles: How much epoxy for a 48 x 24 coffee table, How much epoxy for a 6 ft dining table, How much epoxy for an 8 ft table and How much epoxy for a 4x8 table top.
• Rounds: How much epoxy for a 36 inch round table, How much epoxy for a 48 inch round table and How much epoxy for a 60 inch round table.
• Metric: How much epoxy for a 200 x 100 cm table. Bare, thirsty wood: How much epoxy for a seal coat on a 6 ft slab.

For every thickness from 1/32 in up, the epoxy coverage chart lists square feet per gallon and square metres per liter. For the whole job — sanding, sealing, pouring, torching and curing — see how to epoxy a table top.

Practical tips

• Level the table first. A flood coat finds the low corner and pools there.
• Tape the underside of the edges before you pour — drips that cure there are much harder to sand off than tape is to peel.
• Mix a full batch for each section you can spread inside the working time. Big tops are poured in several batches back to back — Epoxyworks (WEST SYSTEM) suggests pre-measuring the batches, because mixed epoxy left sitting in the pot heats itself up and thickens sooner.
• Check the product’s working time at your room temperature — the cure time calculator adjusts the label figure for a cool or warm shop.