Yes, completely free with no signup required.

Does my data leave my device?

No. All calculations happen in your browser — nothing is sent to a server.

Does it work on mobile?

Yes. The tool is mobile-first and works on any modern browser.

部屋の寸法から壁と天井に必要なペンキのガロン数を計算。

Room length (ft) Room width (ft) Ceiling height (ft) Number of doors Number of windows Coats

Enter your room length, width, and ceiling height in feet.
Add the number of standard doors (20 sqft each) and windows (15 sqft each) to subtract.
Choose 1 or 2 coats — results update instantly showing gallons needed.

Is this tool free?: Yes, completely free with no signup required.
Does my data leave my device?: No. All calculations happen in your browser — nothing is sent to a server.
Does it work on mobile?: Yes. The tool is mobile-first and works on any modern browser.

Last updated: 2026-05-20 By jarvisbox