Epoxy Coverage per Gallon: How Far Does One Gallon Go?
Updated 2026-10-19
"How many square feet does a gallon of epoxy cover?" depends almost entirely on thickness. A gallon is a fixed volume — 231 cubic inches in the US system — so thinner coats stretch farther and thicker coats cover less area. This guide gives a clear coverage chart, the formula behind it, and how to adjust for real-world waste and edges.
To size a specific tabletop or bar top, use the tabletop epoxy calculator.
The coverage formula
Sq ft per gallon = 231 ÷ (144 × thickness_in_inches)
in³ per sq ft = 144 × thickness
Gallons needed = (area_sq_ft × 144 × thickness × coats) ÷ 231
Because 1 sq ft = 144 in², a coat that is T inches thick uses 144 × T cubic inches on every square foot.
Coverage chart (theoretical film only)
| Coat thickness | in³ / sq ft | Sq ft / gallon | Fl oz / sq ft |
|---|---|---|---|
| 1/32 in (0.03125) | 4.5 | ~51.3 | ~2.5 |
| 1/16 in (0.0625) | 9 | ~25.7 | ~5.0 |
| 1/8 in (0.125) | 18 | ~12.8 | ~10.0 |
| 3/16 in (0.1875) | 27 | ~8.6 | ~15.0 |
| 1/4 in (0.25) | 36 | ~6.4 | ~20.0 |
| 1/2 in (0.5) | 72 | ~3.2 | ~39.9 |
| 1 in (1.0) | 144 | ~1.6 | ~79.8 |
Values use 1 US gal = 231 in³ and 1 fl oz ≈ 1.8047 in³. They assume a perfectly even film with no waste, no runoff and no soak-in. Real coverage is lower.
Why 1/8 inch is the usual reference
Many tabletop and bar-top epoxies are marketed around a 1/8-inch flood coat. At that thickness, one gallon covers about 12.8 sq ft on paper — often rounded in marketing to "12–13 sq ft." After drip edges and cup waste, DIY results commonly land closer to the low teens or below. Always stay within the maximum thickness on your TDS; coating epoxy poured much thicker can overheat. See deep pour vs tabletop epoxy.
Worked example: 20 sq ft bar top
One flood coat at 1/8 inch:
- Volume: 20 × 18 = 360 in³
- Gallons: 360 ÷ 231 ≈ 1.56 gal
- Plus 15% waste: ≈ 1.79 gal
- Theoretical coverage check: 20 ÷ 12.8 ≈ 1.56 gal before waste — matches
If you also apply a thin seal coat at roughly 1/16 inch equivalent spread:
- Seal volume: 20 × 9 = 180 in³ ≈ 0.78 gal before waste
- Combined project epoxy rises accordingly
More on sequencing: seal coat vs flood coat and how much epoxy for a tabletop.
Edges reduce "square feet per gallon"
Coverage charts describe flat area. Vertical drip faces use epoxy too. A long bar rail can add a meaningful fraction of a gallon. Measure edge length × edge height, treat that as extra area at the same film thickness, and add it before converting to gallons.
Multiple coats
Two flood coats double the film volume if each is the same thickness. Some schedules use a thinner first build coat and a full flood second — calculate each coat separately rather than guessing. Respect recoat windows on the TDS (sanding may be required if you wait too long).
Deep pours are not "coverage" problems
River tables and void fills are volume fills, not thin-film coverage. Use cubic inches of the cavity and the deep pour calculator or river table calculator. Quoting "sq ft per gallon" for a 1.5-inch river pour is misleading — at 1.5 in, one gallon covers only about 231 ÷ (144 × 1.5) ≈ 1.07 sq ft of that thickness.
Metric quick view
- 1 US gal ≈ 3.785 L
- 1 in³ ≈ 16.387 ml
- At 3 mm ≈ 0.118 in (close to 1/8 in), coverage is in the same ballpark as the 1/8-inch row above
If you work in cm, volume cm³ ÷ 1000 = liters; stay consistent and convert once at the end.
Why manufacturer coverage claims differ
Published coverage may assume a specific thickness, a skilled application with minimal waste, or a different film build. Porous substrates drink more. Pigments and additives can change how the epoxy levels. Treat chart numbers as planning tools, then verify against your TDS and a small test board when the finish is critical.
Shopping from coverage
- Measure area and edges.
- Pick thickness per coat from the TDS.
- Compute gallons from the formula or chart.
- Add 10–20% waste (more for heavy drip edges or first projects).
- Add seal-coat volume if required.
- Round up to kit sizes; confirm whether the label's gallons are combined A+B.
Common mistakes
- Using paint coverage instincts. Paint is often applied much thinner than epoxy flood coats.
- Ignoring that two coats need roughly twice the resin (at the same thickness).
- Buying for theoretical 12.8 sq ft/gal with no waste buffer.
- Mixing units (feet and inches) mid-formula.
Quick reference: gallons for common table sizes at 1/8 inch
Theoretical flood-coat volume only (no edges, no waste), using 18 in³ per square foot:
| Top size | Area | Gallons @ 1/8 in | +15% waste |
|---|---|---|---|
| 48 × 24 in | 8 sq ft | 0.62 | 0.72 |
| 60 × 30 in | 12.5 sq ft | 0.97 | 1.12 |
| 72 × 36 in | 18 sq ft | 1.40 | 1.61 |
| 96 × 30 in | 20 sq ft | 1.56 | 1.79 |
Add edge faces and any seal coat on top of these numbers. For step-by-step tabletop sizing, see how much epoxy for a tabletop.
Fluid ounces and liters from the same chart
Some kits are labeled in fluid ounces. Because 1 gal = 128 fl oz, the 1/8-inch row (~12.8 sq ft/gal) is also about 10 fl oz per square foot of film (18 ÷ 1.8047 ≈ 10). In liters, one US gallon is about 3.785 L, so 12.8 sq ft/gal is roughly 0.30 L per square foot at 1/8 inch before waste.
Coverage vs cost planning
Once you know gallons, multiply by the price you actually pay per kit gallon to estimate material cost, then divide by area for a cost per square foot. Local prices vary widely, so build the number from your receipt rather than a national average. The method is spelled out in epoxy countertop cost per square foot.
Summary
One US gallon is 231 in³. At 1/8 inch, that is about 12.8 sq ft of theoretical coverage; at 1/16 inch, about 25.7 sq ft. Real projects need more resin for waste, edges and seal coats. Calculate from thickness rather than memorizing a single marketing number, and size your pour with the tabletop epoxy calculator.