Coating coverage table
Theoretical coverage comes from one identity: a US gallon of solid material covers 1604 square feet at 1 mil dry. Multiply by volume solids and divide by target DFT in mils to get square feet per gallon.
Real jobs never achieve theoretical coverage. Apply a loss factor for overspray, surface roughness, dead volume in equipment, and irregular geometry - 15 to 40 percent losses are common territory depending on the application method and structure.
| DFT (mils) | DFT (µm) | 50% solids | 60% solids | 70% solids | 80% solids | 90% solids | 100% solids |
|---|---|---|---|---|---|---|---|
| 1 | 25 | 802 | 962 | 1123 | 1283 | 1444 | 1604 |
| 2 | 51 | 401 | 481 | 561 | 642 | 722 | 802 |
| 3 | 76 | 267 | 321 | 374 | 428 | 481 | 535 |
| 4 | 102 | 201 | 241 | 281 | 321 | 361 | 401 |
| 5 | 127 | 160 | 192 | 225 | 257 | 289 | 321 |
| 6 | 152 | 134 | 160 | 187 | 214 | 241 | 267 |
| 8 | 203 | 100 | 120 | 140 | 160 | 180 | 201 |
| 10 | 254 | 80 | 96 | 112 | 128 | 144 | 160 |
| 12 | 305 | 67 | 80 | 94 | 107 | 120 | 134 |
| 16 | 406 | 50 | 60 | 70 | 80 | 90 | 100 |
| 20 | 508 | 40 | 48 | 56 | 64 | 72 | 80 |
Frequently asked questions
How do I calculate theoretical coverage?
Coverage in square feet per US gallon = 1604 x volume solids fraction / DFT in mils. For example, a 70 percent solids coating at 5 mils DFT covers about 225 square feet per gallon before losses.
Where does the 1604 constant come from?
One US gallon spread at exactly 1 mil thickness covers 1604 square feet. It is a unit conversion, not a product property, so it applies to any coating once you know its volume solids.
What loss factor should I use?
It depends on method and geometry. Conventional spray on open steel loses more than airless on flat plate; complex lattice structures lose the most. Many estimators start at 20 to 30 percent and adjust from job history. The project's own records are the best source.