Most large epoxy projects — river tables, garage floors, and commercial coatings — are bought and planned by the gallon. This guide translates your project dimensions directly into gallon estimates, so you can shop confidently. For exact figures with your actual dimensions, use the free epoxy calculator which shows results in gallons alongside fl oz and liters.
Enter your dimensions and see exactly how many gallons you need — with a full cost breakdown.
🪣 Calculate Gallons Now ⟶Epoxy calculators typically output results in fluid ounces. Here's how to convert to gallons (1 US gallon = 128 fl oz):
| Fluid Ounces | Gallons | Quarts | Approximate Kit Size |
|---|---|---|---|
| 32 fl oz | 0.25 gal | 1 qt | 1-quart kit |
| 64 fl oz | 0.5 gal | 2 qt | ½-gallon kit |
| 128 fl oz | 1 gal | 4 qt | 1-gallon kit |
| 256 fl oz | 2 gal | 8 qt | 2-gallon kit |
| 640 fl oz | 5 gal | 20 qt | 5-gallon kit |
| 1,280 fl oz | 10 gal | 40 qt | 10-gallon kit |
These estimates use a typical river channel at 85% void fill, 1.5″ pour depth, with a 10% waste buffer. River width scales with table length for proportion:
| Table Length | River Width | Net Volume | With 10% Buffer | Kit to Buy |
|---|---|---|---|---|
| 3 ft (36″) | 6″ | 100 fl oz | 110 fl oz (0.86 gal) | 1-gal kit |
| 4 ft (48″) | 7″ | 158 fl oz | 174 fl oz (1.36 gal) | 2-gal kit |
| 5 ft (60″) | 8″ | 226 fl oz | 249 fl oz (1.94 gal) | 2-gal kit |
| 6 ft (72″) | 8″ | 271 fl oz | 298 fl oz (2.33 gal) | 3-gal kit |
| 7 ft (84″) | 9″ | 356 fl oz | 392 fl oz (3.06 gal) | 4-gal kit |
| 8 ft (96″) | 10″ | 451 fl oz | 496 fl oz (3.88 gal) | 5-gal kit |
Wider or deeper river channels require significantly more. Use the river table calculator with your exact dimensions.
Coverage drops as coat thickness increases. These are per-gallon estimates on smooth concrete at 100% efficiency (real coverage is typically 80–90% of ideal due to waste):
| Coat Thickness | Sq Ft per Gallon (ideal) | Sq Ft per Gallon (real) |
|---|---|---|
| 1/32″ (thin seal) | 32 sq ft | 25–28 sq ft |
| 1/16″ (62 mil) | 16 sq ft | 13–15 sq ft |
| 1/8″ (125 mil) | 8 sq ft | 6.5–7.5 sq ft |
| 3/16″ | 5.3 sq ft | 4.5–5 sq ft |
| 1/4″ (self-leveling) | 4 sq ft | 3–3.5 sq ft |
For a 400 sq ft garage floor at 1/8″ (2 coats): 400 ÷ 8 × 2 = 100 gallons net. With 15% waste buffer and 1.15× porosity = approximately 13 gallons total. Use the garage floor calculator for your exact area.
Always round up to the next kit size. Running out mid-pour and mixing a second batch risks color inconsistency — especially with tinted pours.
A typical 6-foot table with an 8″ × 1.5″ channel at 85% void fill needs approximately 2.3–3.5 gallons depending on depth and number of pours. Smaller 4-foot tables: ~1.5 gallons. 8-foot tables: 4–5 gallons. Use your exact channel dimensions in the calculator for accuracy.
At 1/16″: ~16 sq ft per gallon. At 1/8″: ~8 sq ft. At 1/4″: ~4 sq ft. These drop 10–20% on porous surfaces due to absorption. Use the coverage calculator for accurate estimates with your floor area and coat thickness.
If your project needs more than 1 quart (32 fl oz), buy gallon kits — they're 20–40% cheaper per ounce. For large floors, 5-gallon kits offer the best value. Never buy multiple quarts when a gallon kit would suffice.
1 gallon = 128 fluid ounces. For a 2:1 mix ratio from 1 gallon: Part A = 85.3 oz, Part B = 42.7 oz. For 1:1 from 1 gallon: 64 oz each. The calculator does this conversion automatically for any ratio and any volume.