Tubes = total bead length divided by what one tube covers
A bead is a triangle of sealant, so the volume it uses per foot depends on the width and the depth. One 300 mL tube holds a fixed volume, so its reach is just that volume divided by the cross-section of your bead. Double the bead width and coverage roughly quarters.
How far one standard 300 mL (10.1 oz) tube goes
| Bead size | Coverage per tube | Tubes per 100 ft |
|---|---|---|
| 1/8 in (3 mm) | ~55 ft | ~2 |
| 3/16 in (5 mm) | ~40 ft | ~2.5 |
| 1/4 in (6 mm) | ~25 ft | ~4 |
| 3/8 in (10 mm) | ~12 ft | ~8 |
| 1/2 in (12 mm) | ~8 ft | ~13 |
Figures assume a square bead (width equals depth). A shallower bead stretches further; a deeper one runs out sooner. For a 600 mL sausage pack, double every coverage number.
What throws the count off
- Waste. Add 5 to 10 percent. Some sealant squeezes past the joint, tooling wipes off material, and the first inch out of a new tube is often uneven.
- Corners. Every inside or outside corner adds a little length and eats extra sealant where beads meet. Count the actual run, not the straight-line distance.
- Backer rod for deep joints. A joint deeper than about 3/8 inch (10 mm) should be packed with foam backer rod first. That caps the effective depth, cuts sealant use, and stops the bead cracking.
- Round up per tube, not at the end. You cannot buy a fraction of a tube, so a job needing 3.2 tubes means buying 4.
Common questions
How many feet of caulk does one tube cover?
A standard 10.1 oz (300 mL) tube covers roughly 55 feet at a 1/8 inch bead, 25 feet at a 1/4 inch bead, or about 12 feet at a 3/8 inch bead. Coverage falls off fast as the bead gets wider because it grows with the square of the bead size.
How many tubes of caulk for a bathtub or shower?
A typical tub or shower perimeter is 12 to 16 feet. At a 1/4 inch bead that is well under one tube, but buy two so you can lay a continuous bead and still have material for a second pass.
What size is a standard caulk tube?
The common cartridge is 10.1 fluid ounces, about 300 mL. Sausage packs run 20 oz (600 mL) and squeeze tubes are usually 2.8 to 5.5 oz. Always divide your total bead volume by the size you are actually buying.
