Navid MoazzezNavid Moazzez

Free Paint Calculator (+ Guide)

A free paint calculator that works out the gallons or liters a room takes, less doors and windows.

Navid Moazzezpar Navid Moazzez·Mis à jour 3 oct. 2026·2 min de lecture·
How much paint you need
Video on Coverr

See how much paint a room takes for the coats you want, less doors and windows.

1

Your numbers

The coverage is on the can's label. Take off the doors and windows you won't paint.

2

Your result

Fill in the fields above to see your result.

Notez cet outil

Intégrer cet outil sur votre site

Collez le code dans n'importe quelle page : WordPress, Webflow, Squarespace, Ghost ou du HTML simple. C'est gratuit avec le crédit en dessous, qui renvoie vers navid.me.

Thème
Fond
Coins
Police

This free paint calculator works out how much paint a room's walls take, in gallons or liters, for the coats you want.

It takes off the doors and windows, and uses the coverage printed on your can.

I built it because paints cover different areas, so a fixed rule of thumb can leave you a can short, or with 2 spare.

Here's the formula, a worked example, and where to find the coverage.

key_takeaways.mdTL;DR

Key takeaways

Wall area = 2 × (length + width) × height, less doors and windows.
Paint = wall area × coats ÷ the coverage on the can's label.
A 14 by 12 foot room with 8 foot walls and 40 square feet of doors and windows has 376 square feet of wall.
At 350 square feet a gallon, 2 coats take 2.15 gallons, so 3 gallon cans.

What is a paint calculator?

A paint calculator turns a room's size into the paint its walls take.

It counts every coat, and leaves out what you won't paint.

How paint is worked out

The walls make a band around the room: the room's perimeter times the wall height.

Work out your paint0/4

A worked example

Here's the example the calculator loads: a 14 by 12 foot room, 8 foot walls, 40 square feet of doors and windows, 2 coats and 350 square feet a gallon.

2 × (14 + 12) × 8 = 416 square feet. Less 40, that's 376. × 2 coats = 752. ÷ 350 = 2.15 gallons, about 8.1 liters.

Where to find the coverage

The can's label lists the coverage a gallon or a liter. If it gives a range, the low end is the safe pick.

Mistakes to avoid

These are the slips that come up most.

  • Forgetting the second coat
  • Leaving the doors and windows in
  • Using another paint's coverage

Who is the paint calculator for?

It's for anyone painting a room, and these tools help around it.

Buy the paint once, and every wall gets the same batch.

Plan your money with your AI

Take your numbers further in

Paint Calculator FAQs

Questions about the paint calculator? Here's what to know.

A paint calculator works out how much paint a room's walls take, in gallons or liters.

Multiply the wall area, less doors and windows, by the coats, and divide by the can's coverage.

With 8 foot walls and 2 coats at 350 square feet a gallon, about 2.2 gallons before doors and windows.

Multiply each one's width by its height, and add them up.

On the can's label, as square feet a gallon or square meters a liter.

A US gallon is about 3.785 liters.

Yes, a ceiling's area is the floor's area, so use the square footage calculator and the can's coverage.

Yes, it's free with no sign-up.

It runs in your browser, and your numbers stay on your device.

I did.

I'm Navid Moazzez, and I made the paint calculator as one of my free tools on navid.me.

More about me.

Navid Moazzez

AI business strategist & AI OS builder

Navid Moazzez helps creators and founders master AI and build their own AI Operating System (AI OS) to automate their business and life.

Navid.me is reader-supported. When you buy through links on this site, I may earn an affiliate commission. Learn more.

Dans le même genre : calculateurs

Plus d'outils gratuits

Serveurs MCP et CLI associés

Newsletter IA gratuite

La newsletter IA la plus concrète pour les fondateurs

Chaque semaine, recevez des stratégies IA éprouvées, des outils sélectionnés et des systèmes pas à pas pour développer votre audience, créer un meilleur contenu et bâtir un business de créateur rentable.

Pas de blabla, pas de remplissage, pas de baratin. Juste cinq minutes par semaine qui peuvent faire passer votre business en ligne et votre vie au niveau supérieur.

P.-S. Inscrivez-vous maintenant pour accéder gratuitement à mon guide ultime des outils IA pour les créateurs.

Apprécié par plus de 10 000 lecteurs