Table of Contents
- Wall area equals perimeter times height, minus doors and windows; multiply by coats and divide by about 350 square feet per gallon.
- Add ceilings, trim, primer and roughly 10 percent extra, and buy all paint at once for consistent color.
- Paint is often a smaller share of a professional job than labor and prep, so cheap paint rarely saves much.
- Gallon and five-gallon buckets usually cost less per gallon than quarts, but only if you will use the paint.
- A calculator gives quantity; a written itemized quote adds prep, labor and building costs.
Most people start a painting project with a trip to the store and a guess. They come home with too little paint, make a second trip, and find the second can is a shade off. Others overbuy and are left with cans that cannot be returned once they have been tinted. A few minutes with a tape measure and the formulas below can prevent both mistakes.
This guide walks through the math for walls, ceilings, trim and exteriors, shows a worked example, covers can sizes and primer, and then places the result in a realistic renovation budget. For the other half of the equation, labor and prep, see our companion NYC paint cost estimator, which focuses on what professional painters charge. This page focuses on quantities and materials.
1. The Basic Formula
Paint coverage is simple once you know the rule of thumb. A gallon of quality interior paint usually covers around 350 to 400 square feet per coat on a smooth, primed surface. Rough, porous or freshly patched surfaces absorb more. For planning, use 350.
The steps:
- Measure each wall. Perimeter of the room times ceiling height gives total wall area.
- Subtract openings. About 20 square feet for a standard door and 15 for an average window.
- Multiply by coats. Two coats is typical; a dark-to-light change may need more.
- Divide by 350. The result is gallons.
- Add 10 percent. For waste, touch-ups, and uneven absorption.
- Round up to the nearest container size.
Do the same for ceilings (length times width) and trim (linear feet times height, usually calculated separately).
2. A Worked Example
Take a bedroom that is 12 feet by 14 feet with 8.5-foot ceilings, one door and two windows.
| Step | Calculation | Result |
|---|---|---|
| Perimeter | 12 + 14 + 12 + 14 | 52 feet |
| Gross wall area | 52 x 8.5 | 442 sq ft |
| Openings | 20 (door) + 15 + 15 (windows) | 50 sq ft |
| Net wall area | 442 - 50 | 392 sq ft |
| Two coats | 392 x 2 | 784 sq ft |
| Wall gallons | 784 / 350 | about 2.2 gallons |
| With 10% extra | 2.2 x 1.1 | about 2.5 gallons |
| Ceiling area | 12 x 14 | 168 sq ft |
| Ceiling, two coats | 168 x 2 / 350 | about 1 gallon |
So a bedroom like this needs roughly three gallons of wall paint and one gallon of ceiling paint, plus a quart of trim paint depending on the amount of baseboard, door and window casing. For an illustration of material cost only, if wall paint is $60 per gallon, three gallons is $180. If it is $90 per gallon, the same gallons cost $270. That is a $90 difference for the whole room, which is why premium paint rarely changes the total much once labor is added.
3. Understanding Can Sizes and Pricing
Paint comes in several sizes. Prices vary by brand, line, sheen and retailer, so check shelf prices before budgeting.
| Container | Typical use | Notes |
|---|---|---|
| Sample pot | Color testing | Small cost, essential before committing |
| Quart | Trim, a feature wall, a small bath | Costs more per ounce; premium quarts can be pricey |
| Gallon | One to two rooms | The common choice |
| 5-gallon bucket | Whole apartments, exteriors | Lower cost per gallon if you will use it |
Premium interior lines run, as a 2026 planning range, around $70 to $100 or more per gallon, while budget lines cost a fraction of that. Tinted paint is usually non-returnable, so measure and calculate before the paint counter tints your color. Ask about contractor or volume pricing, seasonal promotions and price matching. For help deciding where better paint pays off, our interior painting guide discusses product tiers and prep.
4. Primer, Patching and Other Materials
Paint is rarely the only line on the shopping list.
- Primer. Needed over bare plaster, patches, stains, glossy surfaces, and big color changes. Coverage is similar to paint, about 300 to 400 square feet per gallon. Primer is often cheaper than premium paint and may save a coat.
- Spackle and joint compound. For patches and cracks.
- Caulk. For gaps at trim and corners.
- Tape, drop cloths and plastic. Protective materials add up on larger jobs.
- Brushes, rollers and trays. A good roller cover and angled brush improve results more than most people expect.
- Sandpaper and sanding sponges. For smoothing.
- Cleaner or degreaser. Kitchens and baths need it.
- Stain-blocking primer. For water stains or smoke.
As a rule, add 10 to 20 percent to your paint cost for supplies on a DIY job, more if repairs are involved.
5. Adjusting for Real-World Conditions
The formulas above assume a smooth, primed wall. Reality is rougher.
- Textured or porous walls absorb more paint. Plan for lower coverage, closer to 250 to 300 square feet per gallon.
- Dark to light changes often need a tinted primer and a third coat.
- Light to dark changes may also require extra coats for even color.
- High ceilings in pre-war apartments and brownstones add area quickly. A ten-foot ceiling in the same bedroom raises wall area by almost 20 percent.
- Lots of trim needs its own calculation.
- Spraying wastes more paint than rolling, though professionals manage this.
- Rental repaints with the same color may need only one coat.
6. Exterior Painting Math
Exteriors follow the same logic with different inputs.
- Measure each wall's width and height and subtract large openings.
- Account for surface type. Smooth siding covers about 350 square feet per gallon, while rough stucco, brick and shingles can use far more.
- Add trim, soffits, fascia, doors, railings and porches separately.
- Plan for primer on bare wood and chalky surfaces.
- Include time for washing, scraping and repair.
For labor and total price, 2026 planning ranges for exterior painting run about $4,000 to $12,000 for a small New York City or Long Island house and $12,000 to $30,000 or more for larger, complex, brick or stucco homes, with scaffolding or sheds adding cost. These are estimates, not quotes. Exterior work on older houses can involve lead-safe rules, discussed below.
7. From Materials Cost to Real Project Cost
Materials are only part of the story. In New York, labor is usually the largest share of a professional painting bill, and prep takes much of that labor. A typical professional estimate covers protection, repairs, priming, two coats, cutting in, cleanup and building paperwork.
Here are 2026 planning ranges, with walls, ceilings, trim and prep included. They are estimates, and a written itemized quote governs.
| Home size | Planning range |
|---|---|
| Studio | $1,500 to $3,000 |
| One bedroom | $2,500 to $5,000 |
| Two bedroom | $4,000 to $8,000 |
| Three bedroom | $6,000 to $12,000 |
Add-ons include skim coating at roughly $2 to $5 per square foot and kitchen cabinet painting at roughly $3,500 to $9,000. Building rules, access, hazmat, finishes and scope all move prices. For a wider view of what else might appear on a renovation budget, read our guide to hidden costs in NYC renovations, and use the Renovation Estimation Calculator when painting is one part of a larger project.
8. DIY or Professional: Doing the Math Honestly
Run the numbers on both. A DIY two-bedroom might cost a few hundred dollars in paint and supplies, but it also costs several weekends, ladder time, furniture moving and the risk of redoing mistakes. A professional job costs more in cash but arrives with insurance, speed and a consistent finish.
The tipping points favor a professional when:
- Walls need real repair or skim coating.
- Ceilings are high or ornate.
- The building requires insurance, paperwork or limited hours.
- The home was built before 1978, and lead-safe practices apply.
- You are painting to a deadline, such as a move, sale or rental turnover.
- You also need tile, flooring or other trades coordinated.
For the DIY route, the Home Painter Handbook walks through technique.
9. Why Quotes Beat Calculators for Total Cost
A calculator tells you how many gallons. It cannot see that a ceiling is bowed, a wall is chalky or an elevator requires a certificate of insurance. That is the gap a written estimate fills. The risk of relying on a calculator alone is not that the math is wrong, but that the project around it is bigger than the math assumes.
When you ask N.Y. Renovation Services for an estimate, we price the materials and the work together. Our quotes show prep, primer, paint line, sheen, coats, labor, building paperwork and schedule as separate lines, with transparent pricing and no hidden fees. We name the paint, so you can check our quantities against your own calculation. If a repaint reveals water damage, plaster failure or a bathroom that needs tile or flooring work, our in-house design-and-build team can scope that into the same project, rather than sending you off to find another trade.
We also handle permitting and co-op or condo paperwork when a project goes beyond painting, and we donate 5% of the total project cost to a nonprofit of your choice. If you are planning something larger, our gut renovation guide and the complete guide to home renovation show how painting fits in the sequence. A free estimate is the simplest way to turn your calculation into a real number. We will also tell you honestly if your quantities are right, if a cheaper paint tier makes sense for ceilings and closets, and if a repair should come before the first coat. Having one accountable crew for prep, painting and any related tile or flooring keeps the schedule short and the invoice clear.
10. Rules and Safety That Affect Your Budget
Several rules affect painting budgets, and N.Y. Renovation Services builds them into each estimate.
- Permits. Cosmetic painting generally does not need a Department of Buildings permit. The DOB permit guide explains when a filing is required, and our permit checklist gives a quick answer.
- Lead. The EPA's RRP rule requires paid contractors disturbing paint in pre-1978 homes, child care facilities and preschools to be certified and follow lead-safe work practices. This adds labor for containment and cleanup.
- Co-ops and condos. Alteration agreements, insurance certificates, elevator reservations and set hours may apply.
- Rental repainting. Under the Housing Maintenance Code, owners of multiple dwellings must repaint apartments every three years and between tenancies.
- Contractor licensing. Residential remodeling work in New York City requires a Home Improvement Contractor license from the Department of Consumer and Worker Protection.
- Outside the city. New Jersey requires home improvement contractor registration, and Long Island counties require contractor licensing through county consumer affairs.
11. Neighborhoods and ZIP Codes We Serve
Paint quantities and costs depend on building types, and the same formulas play out differently across areas.
- Chinatown, Manhattan (10013, 10002). Mixed-use walk-ups and older tenement stock with commercial-residential buildings. Rooms are often small, but ceilings and layered paint raise prep. See our Chinatown painting page.
- Ditmas Park, Brooklyn (11226). Detached Victorian wood-frame houses in LPC districts, with large rooms, tall ceilings and lots of trim, so quantity calculations should include millwork.
- Astoria, Queens (11102, 11103, 11105, 11106). Attached brick row houses, pre-war walk-ups and new condos. See the Astoria painting page.
- West Brighton, Staten Island (10310). Older wood-frame homes and two-family houses, where exterior and interior painting often combine.
- Valley Stream, Nassau County (11580, 11581). Capes and colonials in the Village of Valley Stream. Exterior surfaces and garages add quantity.
- Tenafly, Bergen County, NJ (07670). N.Y. Renovation Services also works here. Colonials on large lots, with big wall areas where bulk buckets save money.
12. Next Steps: Get Your Free Estimate
You now have the math. If you want it checked or turned into a firm price, send photos and room sizes through the online quote form, or call (347) 455-1741. You can text, too.
N.Y. Renovation Services will review your scope, schedule a walkthrough when repairs are likely, and send a free, written, itemized estimate. For more how-to material, browse the Home Painter Handbook or return to the NYC renovation cost guide.
Safety Note: All work follows OSHA 30 safety and EPA Lead-Safe practices for pre-1978 homes. Check local permit requirements before starting.
James - Lead Renovation Editor. With over 20 years in renovation and construction, James writes and edits our guides. More about James