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Waterproofing/CALCULATOR 04

Joint sealant Calculator

Calculate sealant volume and cartridge quantities.

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How to use this calculator

01

Your measurements

Choose the unit beside each measurement. Changing a unit converts your value.

m
mm
mm
L
%

View your estimate

For a rectangular joint cross-section. Tooling losses, backer rod profile and variable joints affect actual usage.

YOUR ESTIMATE

Cartridges to buy

5
Sealant volume1.32 L
Yield per cartridge5 m

Whole quantities are rounded up.

PLAN YOUR PROJECT COST

Pricing calculator

Use your supplier’s rate or enter a quoted total. Save each estimate to your project and print everything together.

Your selected quantity already includes any allowance shown in that result. Check whether you are pricing individual items or whole packs. Delivery, tax and labour are not added automatically. A quoted total applies only to this saved calculation.

Joint sealant Calculator: measuring notes and method

Split joints with different sizes

Calculate each width and filled depth separately. An average width may conceal wide sections that consume more sealant, especially where depth also changes.

Convert cartridge volume correctly

A 300 mL cartridge is 0.3 L. For a 10 mm × 6 mm rectangular bead, its theoretical yield is 5 m before waste.

CHECK A PRACTICAL EXAMPLE

Cartridge yield depends on filled joint depth

The joint is 20 m long and 10 mm wide. Both examples use 300 mL cartridges and no allowance.

A deeper rectangular bead consumes more material per metre. Use the specified filled profile; backing materials and product joint design are separate from cartridge arithmetic.

Fixed comparison in metric units. Values are illustrative unless linked to a recorded project; changing the calculator above does not change this example.

Formula

Sealant volume = joint length × width × depth × (1 + waste ÷ 100). Cartridges = volume ÷ cartridge volume, rounded up.

Worked examples in metric and imperial units

Illustrative values match Reset example and stay fixed when you edit the calculator. Both columns describe the same calculation; converted inputs are rounded.

Metric worked example

Joint length
20 m
Joint width
10 mm
Joint depth
6 mm
Cartridge volume
0.3 L
Waste allowance
10 %

Cartridges to buy: 5

Imperial worked example

Joint length
65.6168 ft
Joint width
0.3937 in
Joint depth
0.2362 in
Cartridge volume
0.0106 ft³
Waste allowance
10 %

Cartridges to buy: 5

Follow the calculation

Lengths in this working are in metres.

  1. Filled volume with allowance = 20 × 0.01 × 0.006 × 1.1 = 1.32 L.
  2. Cartridge volume = 0.3 L. Divide required litres by cartridge litres and round up.

Unit conversions

1 m³ = 1,000 L ≈ 1.30795 yd³. One cubic yard is 27 ft³.

Reviewed 19 October 2026. How calculations are checked · Report a correction

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PRACTICAL READING

Understand the inputs. Check the order.

Measurement methods and worked examples to use alongside this calculator.

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