Paint consumption calculator
How much paint to order for a coat, from the area, the dry film thickness, the volume solids and your expected losses.
This tool is a reference aid. Before you act on a result, check it against your specification and the product data sheet.
The method: theoretical spreading rate = 10 × volume solids % ÷ DFT (µm). Practical rate = theoretical × loss factor. Paint needed = area ÷ practical rate, rounded up to whole packs.
Worked example
600 m², 200 µm DFT, 70 % volume solids, 30 % losses. Theoretical rate 10 × 70 ÷ 200 = 3.5 m²/L. Loss factor 0.70, practical rate 2.45 m²/L. Paint 600 ÷ 2.45 ≈ 244.9 L: order 13 × 20 L = 260 L. The 10 % thinner sets the wet film (≈ 314 µm) and does not add to the order.
Traps
- Loss factor (below 1) multiplies the spreading rate; consumption factor (above 1) multiplies the volume. Mixing them sends the answer the wrong way.
- Work per coat and add the coats.
Try it in an exam-style question. The FROSIO book teaches this calculation, and its exam hands out the formulas. The free readiness check shows the question style and explains every answer.
Take the free readiness checkSee the tracksRelated: The FROSIO calculation, worked end to end · WFT ↔ DFT calculator · Steel surface area.
Sources
- Paint manufacturers' technical data sheets: theoretical spreading rate from volume solids and DFT
Checked on 4 October 2026. CoatMentor is an independent study aid; it is not affiliated with ISO, AMPP, SSPC, NACE International, ASTM or FROSIO.