Interior Paint Cost Calculator

What this interior painting cost calculator does

This interior painting cost calculator answers two linked questions: how much paint to buy for your walls, and what a reasonable installed interior painting band looks like when you hire a pro. It uses paintable wall square footage, coat count, paint quality tier, and a DIY vs professional switch—then applies a regional labor index for contractor work.

Figuring paintable wall area

Measure each wall’s width times height and sum the results. Do not subtract doors and windows unless you are doing your own detailed takeoff; painters often quote gross wall area because trim and cutting time remain. A 900 sq ft input might represent a few bedrooms and a hallway, not an entire 900 sq ft floor plate (which would include floors and omit ceilings). For whole-home jobs, add all rooms or use your floor plan’s wall length schedule if you have one.

Double-height entries, open stair wells, and gallery walls above railings add square footage quickly. If you are painting ceilings the same color, add ceiling area to your mental budget even though this widget labels input as wall area—many owners run a separate ceiling line item with painters.

Gallons, coats, and coverage math

Industry planning often assumes 350 square feet of coverage per gallon per coat on smooth drywall—your brand’s spec sheet may say 350–400. The calculator rounds gallons up so you do not under-buy. Dark-to-light color changes, porous new drywall, and red or deep bases frequently need an extra coat or tinted primer; the scenario table shows 1, 2, and 3 coat mid totals so you can stress-test coverage.

Textured walls, brick skim coats, and popcorn ceilings reduce effective coverage—buy an extra gallon on the first trip if you are covering heavy orange peel. Sprayers use more paint than rollers on the same wall but save labor; this model uses planning gallons typical of brush-and-roll residential work.

Paint quality and materials line

• Economy: Builder-grade lines—fine for rentals or interim refreshes.
• Standard: Mid-tier washable acrylic—the default for most owner-occupied repaints.
• Premium: Low-VOC, one-coat, or designer lines with higher solids content.

A flat supplies allowance covers rollers, brushes, tape, and drop cloths on DIY runs; pros roll consumables into labor but still buy paint on your specification.

DIY vs professional labor bands

Select DIY (materials only) when you are comparing big-box receipts—labor is zero and low, mid, and high collapse to the same materials total. Professional adds labor priced per square foot of wall area (not per coat in the rate table—the coat count affects gallons and implicit time). Low labor assumes simple rectangles and minimal furniture moving; high labor captures cut-ins, cathedral ceilings, heavy prep, and occupied-home logistics.

Pros often quote one coat of similar color as a touch-up rate and two coats for color changes—your coat input should match the specification you give bidders. Moving furniture, masking built-ins, and patching nail holes are sometimes bundled into labor per foot; ask explicitly. Weekend or after-hours work in occupied offices can index above the high band in this tool.

What this tool does not model

Ceiling-only repaints, cabinet spraying, wallpaper stripping, lead-safe protocols, skim coating, and exterior siding are out of scope. Trim and door painting may be quoted separately as lineal feet. Always confirm whether a painter’s bid includes primer, caulking, and patch repair.

Accent walls with deep pigments, metallics, or faux finishes are specialty trades. HOA color approval and move-out repaints for rentals often standardize on two-coat eggshell—your coat count in the widget should mirror the spec sheet you hand contractors.

Related finish and remodel calculators

Fresh paint usually follows drywall—use the drywall cost calculator for hang-and-finish budgeting. Room-scale remodels tie to the kitchen remodel cost calculator and flooring cost calculator. Ceiling texture removal links to the popcorn ceiling removal cost calculator; worn hardwood may need the hardwood floor refinishing cost calculator before you finalize wall colors.

Disclaimer

Educational planning only. Interior painting costs vary by prep, access, and local labor rates. Obtain written proposals from licensed painters for your home.