Free tool
Paint Estimator
Estimate gallons of finish paint and primer from wall area, coats, and product coverage. Runs the same coverage math as the Drevanto Instant interior-paint assembly — deterministic, no AI in the loop.
Result
Results updated.
| Finish paint | 6gal |
|---|---|
| Primer | 3gal |
Formula
- finish gallons = ceil(area × coats × (1 + waste) ÷ 400 sq ft per gal)
- primer gallons = ceil(area × primer coats × (1 + waste) ÷ 400 sq ft per gal)
Assumptions
- 400 sq ft per gallon coverage — a common manufacturer rating for smooth, sealed surfaces.
- Area is the net paintable surface (subtract large openings before entering it).
What this does not cover
- Rough, porous, or unpainted surfaces can cut coverage dramatically.
- Trim, doors, and ceilings often use different products — estimate them separately.
Planning aid only — not a quote. Quantities use documented rules of thumb; verify against your plans, local codes, site conditions, and real supplier pricing before ordering or bidding.
Methodology
Paint takeoff is coverage division. Multiply the wall area by the number of finish coats and the waste factor, then divide by the product's coverage rate (default 400 sq ft per gallon) and round up — you buy whole gallons. Primer is computed the same way with its own coat count. Openings under roughly 15 sq ft (a standard door) are usually ignored on interior repaints because cutting around them consumes what they save; only large openings should be subtracted from your area input.
Worked example: 1,000 sq ft of wall, 2 coats, primer, 10% waste
- Finish = 1,000 × 2 × 1.1 = 2,200 sq ft ÷ 400 = 5.5 → 6 gallons
- Primer = 1,000 × 1 × 1.1 = 1,100 sq ft ÷ 400 = 2.75 → 3 gallons
Frequently asked questions
What coverage rate should I use?
Use the spread rate printed on the product's technical data sheet, not the front label. 400 sq ft/gal is typical for quality interior paint; heavy textures and deep colors cover less.
Does this estimate labor?
No — it only estimates gallons. Paint labor depends on your crew's own production rates; for a full supported scope, run it through Drevanto's certified painting assembly — see the certified example on the Instant Estimates page.
Should I subtract windows and doors?
Only if they are unusually large. Standard openings are traditionally left in because cut-in time and roller waste offset the saved area.
Certified benchmark · 2026-08-21
In 520 certified profile-mode generations across 26 supported Instant assemblies on Windows (profile/AOT) and an Android API 36 emulator, supported jobs became editable estimates in a median of 0.028 seconds (rounded); the measured 95th percentile was 48.008 milliseconds (approximately 0.048 seconds), with 0 generative-AI provider calls.
- median, supported jobs
- 0.028 sec
- certified generations
- 520
- supported assemblies
- 26
- failures · 0 AI provider calls
- 0
Certified supported jobs only. Editable output; contractor pricing and field verification remain in control. Full methodology and results
See it run on your own jobs
The private Drevanto beta is the real, editable product — not a website demo. Apply, and we will follow up by email.