Paint calculator

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Paint calculator

How many litres a room takes, and how many tins that is.

It runs entirely in this browser tab: nothing you type is uploaded, and it makes no request of any kind.

Settings

The surface
Plaster drinks a third more than a painted wall, and it is why people run out. Choices: Sealed or already painted, Fresh plaster, Bare wood, Masonry.
Coats
Two is the usual; a strong colour change over a light wall wants three. A number from 1 to 4.
Paint the ceiling too
On or off. Starts on.
Take off the openings
One door and two windows is about four and a half square metres.
Tin size
In litres. The count rounds up: half a tin is a tin you have to buy. A number from 1 to 20.
Price each
Leave it empty and the money is left out entirely.
Reserve
A trade convention rather than a measurement: the quantity without it is shown too. A number from 0 to 40.

How to use it

  1. Paste your text into the box above, or open a file.
  2. Adjust the settings beside it until the result is what you wanted.
  3. Copy the result, or save it as a file. The result updates as you type.

Questions

Where do the coverage rates and densities come from?
They are the published typical figures — what a tin of emulsion claims, what a cubic metre of dry sand weighs, what a bag of screed covers. They are printed on the result so you can compare them with the bag in front of you, and the bag wins.
Is the ten per cent reserve part of the calculation?
No, and that is why it is a setting. It is a trade convention for breakage and offcuts, and the quantity without it is shown on the same result, so you can order either.
Can I use this instead of a heating engineer or a structural check?
No. A heat loss from six fields is an order of magnitude, not a design: a standard calculation takes every room, orientation and junction separately. The snow tool weighs snow; whether your roof carries it is on its drawings.
Does anything I type here leave the page?
No. There is no account, no server and no network request. What you type stays in this tab, and in the link if you choose to share one.

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