Enter the length of joint to seal and the size of bead you will run. The calculator converts the cartridge volume into feet of bead and tells you how many tubes of caulk or sealant to buy.
Caulk formula
Cartridge volume (cu in) = fluid ounces × 1.8047 Bead cross-section (sq in) = π × (diameter ÷ 2)² Feet per tube = volume ÷ cross-section ÷ 12 Tubes = joint length × (1 + waste %) ÷ feet per tube, rounded up
One US fluid ounce is 1.8047 cubic inches (NIST), so a 10.1 fl oz tube holds about 18.2 cubic inches. Doubling the bead diameter quarters the length you get from a tube.
Worked example: 100 ft of trim, 1/4 in bead
- Tube volume: 10.1 × 1.8047 = 18.23 cu in.
- Bead area: π × 0.125² = 0.0491 sq in.
- Feet per tube: 18.23 ÷ 0.0491 ÷ 12 = 30.9 ft.
- With 10% waste: 110 ÷ 30.9 = 4 tubes.
Feet of bead per 10.1 oz tube
| Bead | Feet per tube |
|---|---|
| 1/8 in | 123.8 |
| 3/16 in | 55 |
| 1/4 in | 30.9 |
| 3/8 in | 13.8 |
| 1/2 in | 7.7 |
These are theoretical lengths for a round bead with nothing left in the tube. Real yields are lower: some caulk stays in the nozzle and tube, and joints are rarely uniform. Keep the waste allowance, and for wide joints use backer rod so you are not filling a deep gap with sealant.
Questions
How far does a tube of caulk go?
About 31 ft at a 1/4 in bead and 124 ft at 1/8 in, before waste.
How many tubes to caulk a bathtub?
A typical tub surround is 10–15 ft of joint, so one 10.1 oz tube is plenty at a 1/4 in bead.
Does the shape of the joint matter?
Yes. A concave bead in a corner uses less than a full round bead; a deep gap uses far more. Measure the joint and choose the closest bead size.
Sources
- NIST Guide to the SI, Appendix B.8: Factors for units listed alphabetically, National Institute of Standards and Technology.
Used for: 1 US fluid ounce = 1.804 687 cubic inches.