Painting tools and calculators

Start with the measurement that matches the quote. Interior estimates are often quoted per square foot of floor area; exterior estimates are usually per square foot of wall surface. Mixing them up is the fastest way to conclude a fair bid is a rip-off, or vice versa.

For a rough interior bracket, multiply your finished floor area by $1–$4 using This Old House's 2026 range, and treat the top of the range as "walls, ceilings and trim, in a house that needs real prep." A whole-interior job in that source runs $1,800–$10,000.

For exteriors, This Old House puts the range at $2.20–$4.40 per square foot, or roughly $4,400–$8,800 on a typical 2,000-square-foot home. Add for two-story access, extensive wood repair, and any home built before 1978 where lead-safe practices apply.

Calculators cannot see your substrate. Rot, failed caulk, chalking, moisture and previous bad paint jobs are the variables that move a real quote, and none of them show up in a formula. Use the number as a bracket, then let three contractors walk the house.

How to choose

Confirm which square footage a quote uses

Floor area or painted surface area. This single question resolves most "why is this bid so different" confusion.

Bracket, don't predict

Produce a low and a high. If all three bids land inside your bracket, price isn't your deciding factor — scope and references are.

Add a line for prep unknowns

On any older exterior, assume some carpentry. Ask each bidder for their hourly change-order rate rather than a guess.

Factor in lead-safe work

Pre-1978 homes require certified firms and containment for covered work. That's real labor, and it belongs in your bracket.

Don't use a calculator to negotiate

Waving a national average at a local contractor rarely produces a better job. Use it to spot outliers, then buy on scope.