Epoxy coverage calculator
Enter the surface, the thickness of one coat and the number of coats. You get the epoxy to mix, or the area that the epoxy you have will cover.
Result
Mixed epoxy
US gal
Area covered
ft²
| Area = length × width | 16.667 ft² |
|---|---|
| One coat = area × thickness | 1.299 US gal |
| Number of coats | 1 |
| All coats = one coat × number of coats | 1.299 US gal |
| Waste allowance = all coats × waste percentage | 0.130 US gal |
| Mixed epoxy to prepare = all coats + waste allowance | 1.429 US gal |
How it works
A coat of epoxy is a thin, even layer, so the amount it takes is the area of the surface times the thickness of the coat. The calculator multiplies that by the number of coats and adds your waste allowance. Turned around, an amount of epoxy divided by the thickness is the area it covers.
Formula
Epoxy for one coat = length × width × thickness. Epoxy to mix = one coat × number of coats × (1 + waste ÷ 100). Area covered = volume ÷ thickness. One US gallon is 231 cubic inches, so at 1/8 inch it covers 231 ÷ 0.125 = 1848 square inches = 12.83 square feet; product pages usually round this to about 12.
Worked example
The calculator opens with this example; the result above is computed from it.
| Input | Value |
|---|---|
| What to work out | Epoxy needed for a surface |
| Length of the surface | 96 in |
| Width of the surface | 25 in |
| Thickness of one coat | 0.125 in |
| Number of coats | 1 |
| Waste allowance | 10 % |
| Mixed epoxy | 1.429 US gal |
| Area covered | 16.67 ft² |
A surface 96 in long and 25 in wide is 16.67 ft². One coat 0.125 in thick takes 1.299 US gal. For the number of coats entered (1) with 10 % waste, mix 1.429 US gal.
Common cases
| Case | Starting values | Mixed epoxy | Area covered |
|---|---|---|---|
| Countertop, eight feet by twenty-five inches, one flood coat an eighth of an inch thick | Length of the surface 96 in; Width of the surface 25 in; Thickness of one coat 0.125 in; Number of coats 1; Waste allowance 10 % | 1.429 US gal | 16.67 ft² |
| Seal coat on the same countertop, a sixteenth of an inch thick | Length of the surface 96 in; Width of the surface 25 in; Thickness of one coat 0.0625 in; Number of coats 1; Waste allowance 10 % | 0.714 US gal | 16.67 ft² |
| Bar top, ten feet by two feet, two flood coats | Length of the surface 120 in; Width of the surface 24 in; Thickness of one coat 0.125 in; Number of coats 2; Waste allowance 10 % | 3.429 US gal | 20.00 ft² |
| Area one US gallon covers at an eighth of an inch | Thickness of one coat 0.125 in; Epoxy you have 1 US gal | 1.000 US gal | 12.83 ft² |
| Area one US gallon covers at a sixteenth of an inch | Thickness of one coat 0.0625 in; Epoxy you have 1 US gal | 1.000 US gal | 25.67 ft² |
Questions and answers
How many square feet does a gallon of epoxy cover?
It depends only on how thick the coat is. Spread 0.125 in thick, 1 US gal of mixed epoxy covers 12.83 ft². Half the thickness covers twice the area.
How far does a gallon go as a seal coat?
A thin seal coat of 0.0625 in uses half as much as a flood coat: 1 US gal covers 25.67 ft².
How much epoxy do I need for a countertop?
Multiply the length by the width by the thickness of the coat. A countertop 96 in by 25 in with one coat 0.125 in thick needs 1.429 US gal of mixed epoxy, including the waste allowance.
Assumptions and limits
- The coat is treated as an even layer over a flat surface. Epoxy that levels thinner or thicker than you planned changes the amount in proportion.
- Edges and epoxy that runs over the sides are not measured separately; cover them with the waste allowance.
- The waste allowance is a share of the net amount. Epoxy that soaks into bare wood is not estimated; a seal coat is the usual way to deal with it.
- Coverage figures on product pages are rounded and some include their own margin. This calculator uses area times thickness only.
- How thick one coat may be depends on the product. Take the thickness from its instructions.
The result is an estimate for planning, not professional advice.
Sources
- TotalBoat epoxy calculator page: volume = length x width x coating thickness; 'approximately 12 sq feet per mixed gallon coverage at 1/8 inch thickness'; add 5-10 % for wasteretrieved 2026-10-12
- Alumilite volume calculator: epoxy surface coating chart in fl oz per sq ft; 1/16 inch recommended for seal coats, 1/8 inch for flood coatingretrieved 2026-10-12
- Omni Calculator, epoxy calculator: coating volume = length x width x height, worked example 96 x 48 x 1 inretrieved 2026-10-12
- Wikipedia: Gallon (the US gallon is legally defined as exactly 231 cubic inches)retrieved 2026-10-12
- NIST SP 811 Appendix B.9: square foot = 9.290304 E-02 m2 (exact), square inch = 6.4516 E-04 m2 (exact), gallon (U.S.) = 3.785412 E-03 m3retrieved 2026-10-12
Last updated:
Method in depth: Epoxy volume formula: how much resin a pour or a coat needs
Cite this page: Resin Math, “Epoxy coverage calculator”, https://resin-math.pages.dev/epoxy-pour/epoxy-coverage-calculator/ (updated 12 October 2026).
Found a mistake? Email handycalc.sites+resinmath@gmail.com.