How Much Epoxy Do I Need?
The answer depends on your project type, surface area, and pour depth. This guide covers every common project — floors, countertops, tabletops, river tables, and molds — with quick-reference tables so you can get to the right number fast.
Enter your exact dimensions and get a precise epoxy estimate instantly.
Use the Free Calculator →Quick Answer by Project Type
Use this table to find a ballpark amount. For exact quantities, measure your dimensions and use the formulas below or the calculator above.
| Project Type | Typical Amount | Key Variable |
|---|---|---|
| Dining table (30×72 in) — flood coat | ~130 fl oz (1 gal) | Table size + coat depth |
| Coffee table (24×48 in) — flood coat | ~58 fl oz (0.45 gal) | Table size + coat depth |
| Countertop (8 linear ft, 25 in deep) | ~90 fl oz (0.7 gal) | Linear feet + depth |
| Garage floor (400 sq ft) — 2 coats | ~8–9 gallons | Area + coat count |
| River table channel (6 ft × 8 in × 1.5 in) | ~86 fl oz (0.67 gal) | Channel dimensions |
| Round coaster mold (4 in × 0.25 in) | ~2.8 fl oz each | Mold volume |
| Small pendant mold (20mm circle, 3mm deep) | ~0.4 fl oz | Mold volume |
The Core Formula
Every epoxy quantity calculation starts with volume. The core formula converts cubic inches to fluid ounces:
Volume (gallons) = fl oz ÷ 128
The constant 1.805 is the cubic inches per fluid ounce of liquid epoxy. For metric (cm³ to mL), 1 cm³ ≈ 1 mL — so metric volume calculations are even simpler.
Epoxy for Floors
Floor coverage is measured in square feet per gallon, not cubic inches. Standard floor epoxy covers 200 sq ft per gallon at 1/16 inch thick, and 100 sq ft at 1/8 inch.
| Floor Area | 1-Coat (1/16 in) | 2-Coat System | 3-Coat System |
|---|---|---|---|
| 100 sq ft | 0.5 gal | 1.1 gal | 1.6 gal |
| 200 sq ft | 1.1 gal | 2.2 gal | 3.3 gal |
| 400 sq ft (2-car garage) | 2.2 gal | 4.4 gal | 6.6 gal |
| 800 sq ft | 4.4 gal | 8.8 gal | 13.2 gal |
| 1,000 sq ft | 5.5 gal | 11.0 gal | 16.5 gal |
All amounts include a 10% waste buffer. See the full floor calculator →
Epoxy for Tabletops
Tabletop projects typically use a seal coat (thin, 1/32 in) followed by one or two flood coats (1/8 in each). Calculate each coat separately and add them together.
| Table Size | Seal Coat | Flood Coat (1/8 in) | 2 Flood Coats |
|---|---|---|---|
| 18×18 in (tile/small) | 4 fl oz | 16 fl oz | 32 fl oz |
| 24×48 in (coffee table) | 16 fl oz | 32 fl oz | 64 fl oz |
| 30×60 in (dining, small) | 25 fl oz | 50 fl oz | 100 fl oz |
| 30×72 in (dining, standard) | 30 fl oz | 60 fl oz | 120 fl oz |
| 36×84 in (large dining) | 42 fl oz | 84 fl oz | 168 fl oz |
| 48×96 in (conference) | 64 fl oz | 128 fl oz (1 gal) | 256 fl oz (2 gal) |
Flood coat amounts include 10% overage. See the full table guide →
Epoxy for River Table Channels
River table channels require precise volume calculations because the channel is a specific 3D shape. Measure the average width, total length, and pour depth.
The 1.15 multiplier adds 15% for wave edges and surface tension along the wood — channels are never perfectly rectangular.
| Channel Dimensions | Volume (fl oz) | Volume (gal) |
|---|---|---|
| 4 ft long × 6 in wide × 1 in deep | ~36 fl oz | 0.28 gal |
| 6 ft long × 8 in wide × 1.5 in deep | ~99 fl oz | 0.77 gal |
| 8 ft long × 10 in wide × 2 in deep | ~198 fl oz | 1.55 gal |
| 8 ft long × 12 in wide × 2 in deep | ~237 fl oz | 1.85 gal |
Epoxy for Molds
Mold projects are pure volume calculations. Measure the mold interior in inches, calculate cubic inches, then divide by 1.805 to get fluid ounces.
Mold Volume Formulas
- Rectangular mold: L × W × D ÷ 1.805 = fl oz
- Cylinder mold: π × r² × height ÷ 1.805 = fl oz
- Sphere mold: (4/3) × π × r³ ÷ 1.805 = fl oz
- Dome/hemisphere: (2/3) × π × r³ ÷ 1.805 = fl oz
Add 10% to account for surface meniscus and mixing losses.
Step-by-Step: Calculating Your Epoxy Amount
- Identify your project type — surface coating (floors, countertops, tabletops) or volume casting (molds, channels).
- Measure your dimensions — length, width, and depth/thickness in inches or feet.
- Calculate volume or area — for surfaces, multiply length × width. For casts, multiply all three dimensions.
- Apply the formula — surface: sq ft ÷ coverage rate = gallons. Cast: cu in ÷ 1.805 = fl oz.
- Add waste buffer — 10% for clean pours, 15–20% for complex shapes or first-time pours.
- Account for coats — multiply by the number of coats for surface projects.
Frequently Asked Questions
How much epoxy do I need for a tabletop?
For a standard tabletop flood coat at 1/8 inch, calculate length × width (in inches) ÷ 1.805 ÷ 128 = gallons. A 30×72 inch dining table needs about 1 gallon for one flood coat, or 2+ gallons for a seal coat plus two flood coats. Always add 10% for waste.
How much epoxy do I need for a floor?
One gallon covers approximately 200 sq ft at 1/16 inch, or 100 sq ft at 1/8 inch. A 400 sq ft garage with two coats at 1/8 inch each needs about 8–9 gallons total including a 10% buffer. Rough or porous concrete can increase consumption by 15–25%.
How do I calculate how much resin I need for a mold?
Measure the interior dimensions in inches, calculate cubic inches (L × W × D for rectangular), then divide by 1.805 to get fluid ounces. Add 10% for overfill and mixing losses. For cylinders, use π × r² × height instead of L × W × D.