Decorator's Reckoner
Reckonersweight 1reckoner · computes, doesn't store
The room is measured, the paint chart is open, and the tin claims a coverage figure you have no intention of trusting blind. The Decorator's Reckoner turns your walls into arithmetic — how much paint or paper a room actually needs — before you are standing in the shop rounding up out of fear. It computes the quantities and keeps nothing, least of all your opinion of the previous owner's wallpaper.
This is not a screenshot. It's the real tool, running right here — go on, put something in it.
Open the demo full-screen: /demos/decorators-reckoner.html
Questions people ask
How do I calculate how much paint I need for a room?
Give it your wall measurements and it computes the area and what that means in tins. You buy what the room needs, plus your own margin for touch-ups, instead of guessing at the shelf.
Can I use it in the shop without a signal?
Yes — it is one HTML file that runs offline in your browser, computes on the spot, and stores nothing. It works in the paint aisle, the empty house, and everywhere else the measuring tape goes.
Who is the Decorator's Reckoner for?
Weekend decorators, first-time homeowners, and anyone staring at a bare room with a tape measure and a budget. If you have ever bought three tins too many or one too few, it is for you.
Fits your knife at weight 1. Nothing here is final — Knife follows Life. Reforging within your tier is free, forever. Add it, drop it, reforge later; the file stays yours either way.