How Much Epoxy for a Bar Top? (Gallons by Size and Thickness)
Updated 2026-10-26
Bar tops are long, narrow surfaces - often 18 to 30 inches deep and 6 to 12 feet long - finished with a clear or tinted epoxy flood coat. Because the length is large and the thickness is usually thin (around 1/8 inch for a self-leveling coat), the total volume is easy to underestimate. This guide walks through the area formula, common bar sizes, edges, seal coats and a realistic waste allowance so you can order the right kit size.
For any custom length x width x thickness, use the tabletop epoxy calculator or the general epoxy resin calculator.
The formula
Area (in2) = length (in) x width (in)
Volume (in3) = area x coat thickness (in)
Gallons = in3 / 231 Fluid ounces = in3 / 1.8047 Liters = in3 x 0.016387
Always convert feet to inches first (multiply by 12). A 1/8 inch flood coat is thickness = 0.125 in.
Common bar top sizes at 1/8 inch flood coat
| Bar size (L x W) | Area (sq ft) | Volume (in3) | Gallons | Fl oz | +10% gal |
|---|---|---|---|---|---|
| 6 ft x 20 in | 10.0 | 180 | 0.78 | 99.7 | 0.86 |
| 8 ft x 24 in | 16.0 | 288 | 1.25 | 159.6 | 1.37 |
| 10 ft x 24 in | 20.0 | 360 | 1.56 | 199.5 | 1.71 |
| 12 ft x 30 in | 30.0 | 540 | 2.34 | 299.2 | 2.57 |
These figures are for a flat top face only. Edges, a seal coat and waste still need to be added (see below).
Worked example: 8 ft x 24 in bar at 1/8 inch
- Convert: 8 ft = 96 in. Area = 96 x 24 = 2,304 in2 (16 sq ft).
- Flood coat volume: 2,304 x 0.125 = 288 in3.
- Gallons: 288 / 231 = 1.25 gal (about 160 fl oz).
- Edges: assume a 1.5 inch apron coated at about 1/16 inch on the long front and two short ends. Perimeter of those three sides is about 96 + 24 + 24 = 144 in. Edge band is about 144 x 1.5 x 0.0625 = 13.5 in3 which is about 0.06 gal.
- Subtotal: 288 + 13.5 = 301.5 in3 which is about 1.31 gal.
- Add 10% waste: 1.31 x 1.10 is about 1.44 gal.
For a 1:1 product that is roughly 0.72 gal Part A + 0.72 gal Part B. Round up to whole kit sizes - a 1.5-gallon or 2-gallon kit is a common shopping choice for this size once you also budget a seal coat.
Do not skip the seal coat
Bare wood (especially softwoods, plywood and open-grain species) absorbs resin and can push air into the flood coat. A thin seal coat - often brushed on at roughly 1/32-1/16 inch equivalent - uses extra material and should be calculated separately. See seal coat vs flood coat and epoxy coverage per gallon for how thin coats scale with area.
Rough seal-coat budget for the 8 x 2 ft example at about 1/32 inch: 2,304 x 0.03125 is about 72 in3 which is about 0.31 gal before waste. Add that to the flood coat total before you buy.
Thicker builds and poured-in bar tops
Most tabletop/coating epoxies are designed for thin layers (often around 1/8 inch per coat). Building a thicker clear layer, embedding coins or filling a recessed bar-top channel means you may need multiple flood coats or a casting resin with a higher max pour depth. Check the product TDS for maximum thickness per pour. The deep pour calculator helps split thick fills into layers; deep pour vs tabletop epoxy explains when to switch resin types.
L-shaped and wraparound bars
Break an L-shaped top into two rectangles, compute each volume, then add them. Do not treat the shared corner as double-filled - each segment contributes its own length x width x thickness once. For curved fronts, estimate average depth and use that as width, or measure the actual surface area with paper templates and convert square inches to volume by multiplying by coat thickness.
Coverage rule of thumb
At a 1/8 inch coat, one US gallon covers about 231 / 0.125 = 1,848 in2, which is 12.8 sq ft. So a 20 sq ft bar face needs roughly 20 / 12.8 = 1.56 gal before edges and waste - matching the 10 ft x 24 in row in the table above. At 1/16 inch the same gallon covers about 25.7 sq ft. Keep this rule handy when a customer quotes square footage instead of length and width. Full coverage tables: epoxy coverage per gallon.
Sq ft per gallon at thickness t (in) = 231 / (t x 144)
Gallons needed = area_sq_ft / (sq ft per gallon)
Part A / Part B shopping check
After you have a total mix volume (flood + edges + seal + waste), split by ratio and confirm both bottles in the kit are large enough:
- 1:1 by volume: each side = total / 2.
- 2:1 by volume: Part A = total x 2/3; Part B = total x 1/3.
- By weight: use the TDS weight ratio and density (often near 1.1 g/cm3, but verify). See mix ratio volume vs weight.
Example: 1.44 gal flood mix at 2:1 needs about 0.96 gal A and 0.48 gal B. A "1.5 gallon kit" that is sold as 1 gal A + 0.5 gal B fits; a true 1:1 "1.5 gallon kit" (0.75 + 0.75) would be short on A for a 2:1 formula.
Temperature and working time on long bars
A 12 ft pour is a race against pot life. Mix only what you can spread within the working time, or stage the bar in sections if the TDS allows blending wet edges. Hot shops shorten pot life; cold shops lengthen cure. Overview: epoxy cure time and temperature. Bubble control tips while the coat is still fluid: how to fix epoxy bubbles.
Summary
An 8 ft x 24 in bar top at a 1/8 inch flood coat needs about 1.25 gallons for the face alone. Add edges, a seal coat and 10-15% waste, then round up to the next kit. Always follow your manufacturer's TDS/SDS for mix ratio, max pour depth, recoat windows and safety.