The practical toolbox

Sealant cartridge calculator

Save up to 20 named estimates in one link. Enter each job’s joint dimensions and cartridge volume, then see the combined shopping total.

MeasurementsChoose your units. Costs, watts and time stay the same.

Save this version with its URL. Bookmark this page or copy its link to reopen your inputs later. Save a new link after making changes. Anyone with the link can read your inputs. Results are recalculated on reopening; print a copy if you need a fixed record.

Create a saved link with AI

Give your AI assistant your measurements or figures and the instructions below. It can create a ready-to-open link for this sealant estimate. Open the link, check the inputs, then bookmark it or copy the URL to reuse it later.

Copy this prompt and add your information:

Read https://www.lejnel.com/sealant-quantity-url-guide.txt and generate a clickable saved-plan URL for my sealant estimate. Convert my units to the guide’s required units. Ask for missing inputs instead of guessing, and explain any assumptions. Return the link and a summary of the inputs used.

Read the URL format and examples · AI instructions for all tools

The URL contains your inputs. Anyone with the link can read them. Future calculator updates may change results; retain a printed copy when you need a fixed record.

Your estimates

Your sealant estimate

Selected estimate

Diagram shows an idealised cross-section. Dotted lines measure between the edges. Not a full-size template or a joint-design recommendation.

How many sealant cartridges do I need?

Multiply total joint length in metres by cross-sectional area in square millimetres to get millilitres. Add your chosen allowance, divide by cartridge volume and round up. For a rectangular joint, area is width × depth. For a right-triangle bead, area is half the product of its perpendicular legs.

Measure before shopping

Add the lengths of all joints that use the same sealant and profile.
Use the product instructions to establish suitable joint dimensions and backing. This tool does not choose them.
Select the closest idealised profile and enter its dimensions.
Read cartridge volume from the label, choose an allowance and review the rounded purchase quantity.

Worked example

A rectangular joint 5 m long, 6 mm wide and 6 mm deep requires 180 ml geometrically. With an illustrative 10% allowance, that becomes 198 ml: one 300 ml cartridge, leaving 102 ml beyond the allowance-adjusted requirement. A triangular bead with the same perpendicular dimensions uses half that geometric volume.

Why can actual usage differ?

Real beads may be concave, irregular or uneven. Tooling losses, nozzle waste, starts and stops, substrate variation and material left in the cartridge affect consumption. The allowance is your estimate of these losses. Nominal leftover is not guaranteed recoverable material.

Can I combine different joint sizes?

Yes. Add up to 20 named estimates, each with its own dimensions, profile, cartridge size and allowance. The shopping total adds the individually rounded cartridge counts. It does not pool leftovers across jobs or assume different sealants are interchangeable. Copy one link to save all estimates, and reopen it to continue editing. Existing single-estimate links still open. Do not average dimensions across different joint sizes.

Does this tell me which sealant to use?

No. It does not determine waterproofing suitability, adhesion, movement capability, primer, backing rod, minimum dimensions or curing time. Consult the specific manufacturer’s instructions and obtain professional advice where needed. It is not a specification or a guarantee of quantity, performance or suitability; verify measurements before buying or applying.

Can I measure in inches?

Choose Imperial for decimal feet of joint length and inches of cross-section dimensions. Links retain metres and millimetres; cartridge volume stays in ml.