Estimate interior wall paint from room perimeter, wall height, and number of coats, with coverage and waste shown clearly.
Bedrooms, living rooms, hallways, and other spaces where wall perimeter is easier to measure than each wall separately.
A 56 ft room perimeter, 8 ft walls, and 2 coats gives a useful baseline for comparing gallon and bucket quantities.
Default example result: 3 gal with 5% allowance.
The calculator uses the displayed formula, applies your waste allowance, and rounds purchase quantities up. Review the assumptions before ordering and confirm product coverage with your supplier.
Formula used: perimeter × height × coats ÷ 350 ft²/gal
Use the number of finish coats you plan to apply. Add primer as a separate consideration when the existing surface or color requires it.
This first version uses room perimeter and does not automatically subtract openings, so consider that when choosing your waste allowance.
This calculator is for preliminary planning and purchasing estimates. It does not replace professional design, local building codes, site conditions, safety checks, or supplier guidance.