Interior Painting Cost Calculator
Build the number yourself before you sign anything — paintable area × your price, plus labor and the line items that quietly inflate a repaint, kept honest with a contingency buffer.
Painting 1,200 sq ft at $2.00 a square foot plus labor and add-ons is about $3,520.00 with 10% contingency (interior walls run about $1.50–$4.00/sq ft all-in — labeled). Enter the prices from your own quotes — a planning estimate, not a bid.
Calculator inputs
Order of operations matters. A meticulous planner prices an interior repaint in the same sequence every time: measure the paintable area first, put a price per square foot on the paint work, add the labor if the crew quotes it separately, total the add-ons that quietly inflate a job (primer, patching and repairs, trim, ceilings, high or vaulted walls, prep and sanding, extra colors), subtract any discount, then keep a contingency in your back pocket for what the walls hide until the first coat goes on. Enter the prices from your own quote — this tool holds no price of its own, so it is right forever.
The two numbers that move the total most are the area and the add-ons, and those are exactly the two most people under-count. Measure the room, do not eyeball it; and write down every add-on before you compare quotes, because a low headline rate that excludes patching and priming is not actually cheaper.
Formula
The estimate is a transparent sum, with a percentage buffer on top:
total = (area_sqft × price_per_sqft + labor + add‑ons − discount) × (1 + contingency%)
Every dollar is one you entered. The contingency is applied last, to the whole subtotal, so it also cushions the labor and add-ons.
Worked example
A 1,200 sq ft interior at $2.00 a square foot is $2,400 of paint work. Add $800 of separately-quoted labor and no add-ons or discount, and the subtotal is $3,200. A 10% contingency brings it to $3,200 × 1.10 = $3,520. That is the planning number to carry into your quote comparison — not a bid.
Measure first, avoid re-orders
Measure first, avoid re-orders:
- Nail the area before the price. Walls are perimeter × wall height minus doors (~21 sq ft) and windows (~15 sq ft); add ceilings (length × width) and trim only if they are in scope. Use the how-much-paint calculator to lock the square footage first.
- List every add-on. Primer on bare or patched drywall, stain-blocking, extra coats for a dark→light change, trim and ceilings, high or vaulted walls, and prep/sanding each carry cost. Missing them is the #1 reason a real invoice beats the estimate.
- Compare like for like. A quote at a lower $/sq ft that excludes prep and priming is not cheaper — fold those into the add-ons before you judge it.
- Keep the buffer. 10% is a sensible default; raise it for older homes, heavy repairs or many colors.
Reference table
Labeled all-in planning bands ($/sq ft) — a sanity guide only. You enter YOUR real price; the band just flags a quote that is oddly low (skipped prep) or high (premium paint, hard access).
| Job | Typical all-in $/sq ft |
|---|---|
| Interior walls | $1.50–$4.00 |
| Walls, ceilings & trim | $2.00–$5.00 |
| Exterior (for comparison) | $1.50–$4.50 |
Frequently asked questions
How much does it cost to paint the interior of a house?
Interior painting typically runs about $2–4 per square foot all-in for walls, ceilings and trim, but the honest answer is: it depends on your area, coats, prep and local labor. Enter your own price per square foot and add-ons above for a planning number, then get itemized written quotes from licensed, insured painters to confirm it.
What is included in a $/sq ft interior painting rate?
Sometimes labor and materials together, sometimes just the paint work with prep and priming billed separately. Always ask. If your rate is paint-only, put the labor and the prep in the labor and add-ons fields so the total is complete.
Why add a contingency to a painting estimate?
Because walls hide their surprises until the first coat — a patch that flashes, a stain that bleeds, a color change that needs a third coat. A 10% contingency keeps a small surprise from blowing the budget. It is a planning cushion, not padding you have to spend.
Does this include primer and patching?
Only if you enter them. Primer, patching and repairs are add-ons on most jobs; total them in the add-ons field. Bare or patched drywall and a dark→light change usually need priming — see the prep & primer reference.
Is this a bid I can hold a painter to?
No. It is a planning estimate from the numbers you enter, not a bid or a contract. Use it to sanity-check quotes and to understand where the money goes; the binding number is the itemized written quote from a licensed, insured painter.