Sealant Quantity Calculator
Length × width × depth straight to cartridges.
Quick answer
With the default inputs: Total joint length 200 · Joint width 10 · Sealant depth 8 etc.Cartridges to buy 57 cartridges
Edit the inputs below to recalculate.Inputs
Result
Cartridges to buy
57cartridges
| Net sealant volume | 16.00L |
| Volume incl. waste | 17.60L |
| Sealant per metre | 80ml/m |
| Pack size | 310ml |
| Cartridges without waste | 52cartridges |
| Metres per cartridge | 3.9m |
Volume = length × width × depth, and depth is not width: with three-sided adhesion a backer rod must control depth, normally about half the width and not less than 6 mm. Too deep wastes sealant, too shallow lacks movement capacity and debonds. Widths are usually at least 6 mm; depth equals width below 8 mm, half the width for 8-12 mm, and 6-8 mm above 12 mm. Allow 10-15% waste for corners, rework and tooling.
Reverse: known result, work out one input
Enter a target result; the other inputs stay fixed and this one is worked out.
Formula
| Volume (ml) = length(mm) × width(mm) × depth(mm) ÷ 1000 | |
| Per metre = width × depth ÷ 1000 | ml/m |
| Cartridges = ceil(volume × (1+waste) ÷ pack size) |
200 m of joint, 10 mm wide, 8 mm deep, 310 ml cartridges with 10% waste: 16000 ml gross, 17600 ml with waste, so 57 cartridges; 80 ml per metre, 3.9 m per cartridge.
How to work it out
- Measure total joint length — accumulate grid joints for facades, perimeters for windows, running metres for movement joints.
- Set the section: joint width as designed, but the sealant depth is not the full depth; take 0.5-0.7 times the width and not less than 6 mm.
- Volume = length × width × depth, with all units in cm so the result is cm³, that is millilitres.
- Divide by the cartridge net content (310 ml, 500 ml, 600 ml foil pack are common) and round up.
- Add 10-15% waste for gun retention, tooling and restarts; take the higher figure at irregular corners.
Where it goes wrong
- Filling the joint to full depth — a polyethylene backer rod goes in first and the sealant is only 6-8 mm deep. Filling solid wastes three times the material and, worse, three-sided adhesion prevents movement and cracks the seal.
- Treating 310 ml as 310 g — silicone densities run 1.0-1.4 g/cm³, so buying by weight and using by volume differs by over 30%.
- Using the drawing joint width rather than the as-built — facade installation tolerance opens joints 3-5 mm wider than design and the calculated quantity runs out.
- Ignoring substrate compatibility — neutral cure silicone is not suitable for every substrate; the wrong sealant is a quality failure, not a quantity error.
Material and cost
Neutral silicone 10-25 CNY per 310 ml cartridge, weatherproof 15-35, structural 30-70. Application 5-12 CNY/m; access equipment extra on facades.
On site
- Substrates must be dry and free of oil and dust; concrete below 8% moisture. Sealing a damp substrate always debonds.
- Mask both sides, tool the joint, then strip the tape — freehand tooling gives uneven width and smears stone or aluminium.
- Keep one brand and one batch across a project; mixing brands can prevent curing altogether.
Basis
- GB/T 14683-2017 Silicone and modified silicone building sealants
- JGJ 102-2003 Technical code for glass curtain wall engineering, Section 3.4
- GB 50345-2012 Technical code for roof engineering, Chapter 5 (joint sealing)
FAQ
Why not make depth equal width?
The sealant must move freely. Movement capability is rated as a percentage of width (say ±25%), and three-sided adhesion locks it in place so it tears from the base under movement. A polyethylene backer rod sets the depth and limits adhesion to the two faces, with depth about half the width to form the proper hourglass section. It is the most basic and most often missed rule.
Why do sites often run short?
Three omissions: the real joint run is longer than drawn (corners and odd shapes add length); tooling and masking consume sealant; and rework happens. Allow 10-15%, or 15-20% for complex façades. Also watch shelf life - do not buy the whole job at once.
Can structural and weatherproof sealants be swapped?
No. Structural silicone carries load and must be proven compatible with the substrates through adhesion and peel tests; it costs several times more. Weatherproof sealant only seals against water and carries no load. Using it to bond façade panels is a serious hazard - glass can fall out whole. They look identical, so check the product designation and test reports.
Cite this page
Use this format in reports, method statements or coursework. The link is permanent.
Building Calculator. Sealant Quantity Calculator. 2026-10-25. https://jianzhujisuan.com/en/sealant-quantity
Results are estimating aids only and are not a design basis. Construction and final accounts must follow the drawings, the applicable standards and an approved method statement. Anything affecting structural safety, shoring or falsework must be checked by a suitably qualified engineer.