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Coving, Skirting & Architrave Calculator
Order too little and you're back at the merchant mid-fit; order too much and there's a stack of offcuts in the garage. Enter the room size, pick what you're running, and get an honest metre-by-metre figure plus the number of lengths to buy — with a bit spared for mitre cuts.
These are estimates — always buy a little extra. Mitres, mistakes and matching the pattern all eat length, and internal/external corners waste more than a straight run.
Every figure here is an estimate. Round up and keep a spare length or two — it's cheaper than a second trip to the merchant.
How do I work out how much skirting board I need?
Measure the perimeter of the room — for a rectangular room that's 2 × (length + width) — then subtract the width of any door openings, because skirting stops at the architrave on each side of a door. Add a wastage allowance of around 10% for the material lost when you cut mitres at the corners, then divide by the length of board you're buying and round up. This calculator does all of that as you type: enter the room size, tell it how many doors and how wide, pick a board length, and it gives you the number of lengths to order.
How much extra should I allow for cutting mitres?
Around 10% is the usual rule of thumb for coving, skirting and architrave. Every mitred corner — internal or external — wastes a wedge of material, and external corners waste more than internal ones. If the room has lots of corners, a bay window, or you want the safety of matching a pattern, bump the wastage to 15% or even 20%. It's always cheaper to have one spare length than to run short two-thirds of the way round and have to go back for more (possibly from a different batch).
How much coving do I need for a room?
Coving runs continuously around the top of the room where the wall meets the ceiling, so unlike skirting there are no door openings to deduct — the coving passes straight over the top of every doorway. The length you need is simply the room perimeter, 2 × (length + width), plus a wastage allowance for the mitred corners. Set the type to "Coving" in the calculator and the door deduction is removed automatically, leaving you with the running length and the number of lengths to buy.
Does this tool store my details?
No. There's no sign-up and nothing to submit — every calculation runs entirely in your browser as you type. Nothing you enter is uploaded, saved or sent anywhere, so you can use it as many times as you like without leaving a trace.
Please note: this tool gives a guide or estimate only. It may not be 100% accurate and is not professional advice — always check the figures before you rely on them. Nothing you enter is uploaded — the calculation runs entirely in your browser.
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