Interior Painting Cost Calculator
| Tier (400 sq ft of wall) | Band | Mid |
|---|---|---|
| DIY materials | $240-480 | $360 |
| Pro standard, two coats | $800-1,600 | $1,200 |
| Pro premium / plaster | $1,600-2,800 | $2,200 |
Interior painting prices in three honest bands per square foot of wall area: DIY paint-and-prime materials run $0.60-1.20; a pro standard two-coat job runs $2-4; and premium work - dark colors, plaster repair, heavy prep - runs $4-7. The band you land in is decided less by paint than by prep: filling, sanding, caulking and masking are most of the hours in a quote, and they are the part DIY quotes quietly skip.
The two lines that move a paint bid the most: ceilings and cut-in work. Ceilings add roughly a dollar a square foot because they mean drops, extension poles and a second color decision. Cut-in work - edging where wall meets trim, ceiling and corners with a brush before rolling - is about half the labor of a professional job, which is why open floor plans with long sight lines price higher per square foot than small choppy rooms full of natural edges.
One legal line dwarfs all of it: if the home was built before 1978, disturbing more than a minor amount of painted surface is federal RRP territory - the renovator must be an EPA Lead-Safe Certified Firm or the job is illegal, not just risky. Sanding through lead paint without containment is the classic self-inflicted poisoning route, and it is why the pre-1978 question is the first one honest contractors ask.
How to use
- Measure the wall area honestly - perimeter x height minus openings is close enough; paint math rounds up to the gallon anyway (use the paint calculator for cans).
- Pick the tier: DIY materials if walls are sound and you own the gear; pro standard for sound walls and standard colors; premium for plaster, dark-over-light, or heavy repair.
- Decide ceilings now, not mid-job: same-visit ceilings price near $1 per square foot extra; "we will do ceilings later" is a second setup, second drop and a second minimum.
- If the home predates 1978, get the RRP answer in writing before sanding starts - certification number, not just a yes.
Frequently asked questions
How much does it cost to paint an interior room?
A 12x12 room (about 400 sq ft of wall) lands mid-band at $360 in DIY materials, $1,200 pro standard, and $2,200 pro premium with typical prep; add roughly $1 per square foot if ceilings join the job. Whole-house numbers scale with area: 2,000 sq ft of wall runs about $4,000-8,000 pro standard depending on region and prep.
How do painters price a job?
Pros quote from wall area x rate, then adjust for prep, height, color change and cut-in density - not from gallons. A quote with no prep line and no number of coats is a bait quote; the honest ones list prep, primer, two finish coats and cleanup as separate lines. Rates concentrate the invisible work: most of a paint job happens before the first finish coat opens.
Is it cheaper to paint yourself?
For sound walls and standard colors, yes - roughly a quarter to a third of the pro price, mostly materials and gear. The DIY discount shrinks with prep (plaster cracks, smoke stains, glossy old oil paint), with ceilings, and with your hours: a 400 sq ft room is a full weekend for a first-timer with two coats. Hiring out the cut-in-and-roll of big open spaces while DIYing closets and bedrooms is the common hybrid.
How many coats of paint do I need?
Two thin finish coats over primer beat one thick coat every time - thin coats level, thick coats sag and the lap marks telegraph in raking light. A dramatic color change needs a tinted primer plus two coats; same-family colors over sound paint often survive with two coats and no primer. Paint covers at its rated spread rate, not at your enthusiasm.
Do I need lead-safe certification for a 1970s house?
If the home predates 1978 and the job disturbs more than 20 sq ft of painted exterior or 6 sq ft interior, federal RRP rules apply: the firm must be EPA Lead-Safe Certified and follow containment and verification - in a pre-1978 home this is the law for hire-out work, not a suggestion. Owners doing their own primary residence are exempt from the certification, not from the lead; wet-sand, never dry-sand, and clean with HEPA.