Expansion joints, window perimeters and control joints are filled with sealant to a depth of about half the width (with a backer rod behind), so the bead can stretch. A standard 10.1 oz cartridge holds 299 mL and fills about 24 ft of a ¼ × ¼ in joint but only 6 ft of a ½ × ½ in joint.
How to use the Sealant Calculator
- Total joint length
- Joint width
- Joint depth
- Package
- Waste
- Price per package
- Every result field is editable: type into Sealant volume and Total joint length plus every other field update to match.
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter the total joint length, the joint width and depth, the package size and a waste allowance. The calculator finds the volume of sealant, the number of packages and how far each one goes.
Tips for an accurate estimate
- Sketch the job and split irregular areas into rectangles, circles and triangles before you measure.
- Add a waste allowance – typically 5–10% for simple layouts and 15–20% for diagonal, curved or heavily cut work.
- Check the coverage or yield printed on the product, because sizes and densities vary between manufacturers.
- Buy all units of a finished material (tile, brick, siding) from the same batch so colours match, and keep a few spares for repairs.
- Confirm local prices – quarry, lumber and steel prices vary widely by region and season.
Common mistakes to avoid
- Ordering exactly the calculated amount with no allowance for breakage, offcuts and settlement.
- Forgetting to subtract doors, windows and other openings – or subtracting small ones that still need cutting around.
- Confusing US short tons (2,000 lb) with metric tonnes (1,000 kg) when comparing quotes.
Inputs explained
| Field | What to enter |
|---|---|
| Total joint length | Units: ft, m, in, yd, cm |
| Joint width | Units: in, cm, mm, ft, m, mm |
| Joint depth | Units: in, cm, mm, ft, m, mm |
| Package | Choose one: 10.1 fl oz cartridge (299 mL), 10.3 fl oz cartridge (305 mL), 20 fl oz sausage (591 mL), 28 fl oz cartridge (828 mL) … |
| Waste | In % |
| Price per package | Units: /piece |
What each result means
- Sealant volume = [Total joint length]×[Joint width]×[Joint depth]×(1 + [Waste]÷100)
- Packages needed = ceil([Sealant volume]÷[Package])
- Joint length per package = [Package]÷([Joint width]×[Joint depth])
- Cost = [Packages needed]×[Price per package]
Example values
How the main result changes when Total joint length changes and everything else stays at the example values above:
| Total joint length (ft) | Sealant volume (fl oz) |
|---|---|
| 50 | 34.3 |
| 75 | 51.4 |
| 100 | 68.6 |
| 125 | 85.7 |
| 150 | 102.9 |
| 200 | 137.1 |
Formula
Volume = joint length × width × depth × (1 + waste)Packages = ceil(volume ÷ package volume)Coverage per package = package volume ÷ (width × depth)Worked example
Inputs — Total joint length: 100 ft; Joint width: 0.375 in; Joint depth: 0.25 in; Package: 10.1 fl oz cartridge (299 mL); Waste: 10 %; Price per package: $8 /piece.
Results — Sealant volume = 68.6 fl oz; Packages needed = 7; Joint length per package = 16.2 ft; Cost = $56.00.
Frequently asked questions
How many feet does a tube of caulk cover?
A 10.1 oz tube covers about 55 ft of ⅛ in bead, 24 ft of ¼ × ¼ in, 11 ft of ⅜ × ¼ in and 6 ft of ½ × ½ in joints.
How deep should sealant be?
Half the joint width for joints ½–1 in wide (minimum ¼ in), and equal to the width for narrower joints.
What is backer rod for?
It controls the sealant depth and prevents three-sided adhesion so the bead can flex.
What formula does the Sealant Calculator use?
Volume = joint length × width × depth × (1 + waste).