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Firewood calculator
The heat in a stack of wood, by species, moisture and how it is sold.
It runs entirely in this browser tab: nothing you type is uploaded, and it makes no request of any kind.
Settings
- Sold as
- Three cubic metres are three different quantities of wood. Choices: Loose, Stacked, Solid.
- Species
- What differs between beech and spruce is the weight of a cubic metre, not the energy in a kilogram. Choices: Beech, Oak, Birch, Ash, Spruce, Pine.
- Stove efficiency
- An open fire is about a quarter; a modern stove is three quarters. A number from 40 to 90.
- Work out the winters
- How many winters the wood covers, from a season's heat you give.
How to use it
- Paste your text into the box above, or open a file.
- Adjust the settings beside it until the result is what you wanted.
- 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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