How to use (3 steps)
- Pick Metric or US units and enter volume solids (v/v%). Density is optional but needed for mass outputs.
- Choose B-3 to start from design DFT or WFT, or B-4 to start from actual consumption per area (volume or mass).
- Results refresh automatically. Adjust inputs as needed and use Copy URL to share the same setup.
A practical sample is preloaded so a result appears immediately.
Settings
Use the volume solids on the product data sheet.
Optional. Enter to show mass per area.
B-3: DFT/WFT & theoretical coverage
Volume solids link DFT and WFT: DFT = WFT × VS% / 100. Coverage = 10 × VS% ÷ DFT (µm).
B-4: Consumption → actual DFT
Volume used per area (L/m² or gal/ft²).
Mass used per area (kg/m² or lb/ft²). Density is required here.
Results
These are theoretical values; real jobs often use more paint due to profile, overlap, overspray, or loss.
Assumes 60% volume solids in metric units. Density is applied for mass outputs.
| Metric | US |
|---|
Interpretation (DFT, WFT, and theoretical coverage)
- WFT (wet film thickness) is measured right after application.
- DFT (dry film thickness) is measured after curing/drying, when the wet film has lost solvents/volatiles.
- Volume solids (v/v%) is the fraction of the wet film that remains as dry film.
Key relations
- DFT = WFT × VS% / 100 (so WFT = DFT × 100 / VS%).
- Theoretical coverage (metric): m²/L = 10 × VS% ÷ DFT (µm).
- Theoretical coverage (US): ft²/gal ≈ 1604 × (VS%/100) ÷ DFT (mil).
Worked example
VS = 60%, target DFT = 100 µm → WFT ≈ 100×100/60 ≈ 167 µm. Theoretical coverage ≈ 10×60/100 = 6.0 m²/L (≈ 244 ft²/gal).
Real consumption is usually higher due to surface profile/roughness, overspray, edge loss, and application efficiency. Use this tool as a planning baseline, then add your project allowances.
References
DFT/WFT planning: separate specification targets from field delivery
Coating calculations are easiest to misread when theoretical values are treated as procurement-ready numbers. This page helps convert between DFT, WFT, and coverage, but field performance still depends on transfer efficiency, profile loss, and operator consistency. Run at least two scenarios: an ideal baseline and a field-adjusted case with realistic efficiency. Procurement and QA decisions should be based on the field-adjusted case, while the theoretical case remains useful for specification cross-checks.
How to run the calculator effectively
- Use supplier data-sheet volume solids as the baseline input.
- Define whether you are solving from required DFT or from known consumption.
- Apply transfer-efficiency assumptions that match spray method and operator maturity.
- Document coat count and substrate profile in the same report.
Common mistakes
- Mixing solids values from different product revisions.
- Using one efficiency value for all coats despite different application passes.
- Ignoring rework/overspray margin when converting to order quantity.
Mini QA scenario
A job requires 80 µm DFT. Theoretical calculation suggests low consumption, but field profile and spray loss increase actual use by 20%. By running both scenarios, the team can justify material allowance and avoid under-ordering. QA then compares measured dry film against the original spec while procurement uses the adjusted volume figure.
See also
- Exterior paint calculator for wall-area demand estimation.
- Roof paint calculator for slope-aware area planning.
- Fence paint calculator for complex geometry cases.
- Epoxy resin calculator for batch and mass planning.
FAQ
Which volume solids value should I enter?
Use the volume solids (v/v%) from the product data sheet. If multiple ranges are given, start with the typical value.
Why is theoretical and actual consumption different?
Profile, surface roughness, edge loss, overspray, and spray efficiency usually make real consumption higher than the theoretical value shown here.
Can this handle multiple coats?
This tool assumes one coating layer at a time. For multi-coat systems, calculate each layer separately and add the DFT totals.
Can I apply different efficiencies per coat?
Yes. Run each coat as a separate scenario when spray setup or substrate condition changes between coats.
Do temperature and viscosity affect WFT planning?
They can affect atomization and transfer behavior. Recheck assumptions when site temperature, thinner ratio, or spray setup changes.