Free tool for builders & estimators
Sealant Quantity Calculator
How many cartridges or sausages does the job need? Enter the joint size and lineal metres — the calculator includes 10% wastage. Handy for estimating; for a full priced scope, get a quote.
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How the maths works
Sealant volume per metre of joint = width (mm) × depth (mm) millilitres. A 10 × 10 mm joint uses 100 ml per metre, so a 300 ml cartridge runs about 3 lineal metres and a 600 ml sausage about 6. We add 10% for wastage — tooling losses, joint variation and part-used tubes.
Rule of thumb for depth: for joints wider than 10 mm, sealant depth should be roughly half the width (a 20 mm joint wants ~10 mm depth over backer rod). Correct depth is set with backer rod — deep-filled joints without it fail early. More in our guide: what a good panel joint looks like.
Estimating a real job — precast panels, fire rated joints, floor joints? Send the metres through the quote form and we'll price the whole thing, materials and labour, free.
Metres per pack, at a glance
How far one pack goes at each joint size — width across the top, depth down the side. Built from the same arithmetic as the calculator above, so the two can never disagree.
Silicone — 300 ml cartridge
| Depth | 6mm | 8mm | 10mm | 12mm | 15mm | 18mm | 20mm | 25mm | 30mm |
|---|---|---|---|---|---|---|---|---|---|
| 3mm | 16.7 | 12.5 | 10 | 8.3 | 6.7 | 5.6 | 5 | 4 | 3.3 |
| 6mm | 8.3 | 6.3 | 5 | 4.2 | 3.3 | 2.8 | 2.5 | 2 | 1.7 |
| 8mm | 6.3 | 4.7 | 3.8 | 3.1 | 2.5 | 2.1 | 1.9 | 1.5 | 1.3 |
| 10mm | 5 | 3.8 | 3 | 2.5 | 2 | 1.7 | 1.5 | 1.2 | 1 |
| 12mm | 4.2 | 3.1 | 2.5 | 2.1 | 1.7 | 1.4 | 1.3 | 1 | 0.8 |
| 15mm | 3.3 | 2.5 | 2 | 1.7 | 1.3 | 1.1 | 1 | 0.8 | 0.7 |
| 20mm | 2.5 | 1.9 | 1.5 | 1.3 | 1 | 0.8 | 0.8 | 0.6 | 0.5 |
Polyurethane — 600 ml sausage
| Depth | 6mm | 8mm | 10mm | 12mm | 15mm | 18mm | 20mm | 25mm | 30mm |
|---|---|---|---|---|---|---|---|---|---|
| 3mm | 33.3 | 25 | 20 | 16.7 | 13.3 | 11.1 | 10 | 8 | 6.7 |
| 6mm | 16.7 | 12.5 | 10 | 8.3 | 6.7 | 5.6 | 5 | 4 | 3.3 |
| 8mm | 12.5 | 9.4 | 7.5 | 6.3 | 5 | 4.2 | 3.8 | 3 | 2.5 |
| 10mm | 10 | 7.5 | 6 | 5 | 4 | 3.3 | 3 | 2.4 | 2 |
| 12mm | 8.3 | 6.3 | 5 | 4.2 | 3.3 | 2.8 | 2.5 | 2 | 1.7 |
| 15mm | 6.7 | 5 | 4 | 3.3 | 2.7 | 2.2 | 2 | 1.6 | 1.3 |
| 20mm | 5 | 3.8 | 3 | 2.5 | 2 | 1.7 | 1.5 | 1.2 | 1 |
These figures are what the joint itself holds — your wastage goes on top. Printed usage charts often lose a decimal below one metre (0.8 shown as 0.08); these are calculated fresh, so they don't.