Project notes
Understand this estimate
A coating estimate can use either a product spread rate or the geometric volume implied by a measured thickness. Each product layer should use its own rate.
How to use the calculator
Select the supported estimating method
Use the label coverage method when a spread rate is available, or thickness mode when you have a supported thickness for this coating.
Inputs Calculation method
Measure the area and selected method input
Enter surface area and only the rate or thickness that matches the selected method.
Inputs Surface area · Product coverage · Thickness per coat
Set coats and optional allowance
Count identical coats for this product. Keep primer, body coat and topcoat estimates separate.
Inputs Coats · Extra allowance
Formula and variables
Coverage method: gallons = area ÷ coverage × coats. Thickness method: gallons = area in ft² × 144 × thickness in inches ÷ 231 × coats. Apply the entered allowance afterward.
- ACoated area
- Area receiving this product.ft²
- CProduct coverage
- Current label rate for one coat.ft²/US gal
- DFilm thickness
- Entered thickness per coat.in
What the result means
Result interpretation
The output is the estimated quantity of one coating product. Coverage and thickness methods are alternatives; the calculator does not verify a suitable film build.
Limits and assumptions
This estimates one product only. Do not combine rates for primer, base and topcoat. Surface texture, porosity and edge runoff are not automatically modeled.
Worked examples
Two coats using a label rate
Assumptions
- The entered rate is 200 ft² per US gallon per coat.
- The same product and rate apply to both coats.
Calculation
- 400 ÷ 200 × 2 = 4 US gal.
| Coating product | 4 US gal |
|---|
One coat from measured thickness
Assumptions
- The coating thickness is 0.125 in over 100 ft².
- The entered thickness is a project specification, not a recommendation.
Calculation
- 100 × 144 × 0.125 ÷ 231 = 7.792 US gal.
| Coating product | 7.792 US gal |
|---|
Common questions
- Should primer and topcoat be combined?
- No. Estimate each product with its own coverage, coat count and instructions.
- Does the thickness method include overspray or porosity?
- No. It is geometric liquid volume and does not estimate application loss.