Caulk Calculator
A tube of caulk goes a long way on a thin bead and disappears fast in a wide gap. Enter how many feet you are sealing, the width and depth of the joint (or pick a corner bead), and the tube size to see how many tubes to buy and how far each one runs.
Your project
Use a corner bead for a caulk line along a tub, trim or countertop edge.
Ignored for a corner bead. Wide joints: fill to about half the width over backer rod, 1/4 in minimum (ASTM C1193).
Your results
- Tubes to buy
- 5 × 10.1 fl oz
- 45.7 fl oz of caulk including waste
- Each tube runs
- 24.3 ft
- before waste
- Bead cross-section
- 0.0625 sq in
- Coverage per gallon
- 308 lineal ft
Estimates use typical US material and labor pricing. Confirm quantities against the coverage chart on the bag before you buy.
Gear for this job
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How this calculator works
- Bead area (sq in) = width × depth, or width² ÷ 2 for a triangular corner bead
- Volume (cu in) = bead area × length (in) × (1 + waste %)
- Tubes = volume ÷ (tube fl oz × 1.8047 cu in per fl oz), rounded up
- Lineal ft per gallon = 231 ÷ bead area ÷ 12
Feet per 10.1 fl oz tube by joint size
| Joint (width × depth) | Ft per tube | Ft per gallon |
|---|---|---|
| 0.125 × 0.125 in | 97.2 | 1,232 |
| 0.25 × 0.25 in | 24.3 | 308 |
| 0.375 × 0.25 in | 16.2 | 205 |
| 0.5 × 0.25 in | 12.2 | 154 |
| 0.75 × 0.375 in | 5.4 | 68 |
| 1 × 0.5 in | 3 | 39 |
Computed with this calculator; the per-gallon column matches Tremco's Joint Sealant Estimating Chart (1/4 × 1/4 in = 308 ft).
How the numbers work
A 10.1 fluid ounce tube holds 18.2 cubic inches (1 US fl oz = 1.8047 cu in, NIST Handbook 44). A 1/4 × 1/4 inch joint uses 0.0625 square inches of sealant per inch of length, so one tube runs about 24.3 feet. Double the width and the same tube covers half the distance; double both width and depth and it covers a quarter.
Sealant makers publish the same arithmetic per gallon: Tremco's estimating chart lists 308 lineal feet per gallon for a 1/4 × 1/4 inch joint, which is exactly 231 cubic inches ÷ 0.0625 ÷ 12.
Sizing the joint
For joints of about 1/2 inch and wider, ASTM C1193 guidance is a sealant depth of roughly half the width, and never less than 1/4 inch, set over closed-cell backer rod so the bead bonds to the two sides only. Stuffing a deep gap full of caulk wastes material and makes a joint that tears when the gap moves. Gaps wider than about 1/4 inch around windows and pipes are better filled with low-expansion foam first.
Air sealing before insulating
Caulk seals the joints that do not move much: trim to drywall, window and door casings, baseboards, top plates in the attic and plumbing penetrations. Seal these before adding insulation; air carries heat and moisture straight through fiberglass. The dew point calculator shows why moist indoor air leaking into a cold wall is a problem.
Frequently asked questions
How many feet does a tube of caulk cover?
A 10.1 fl oz tube covers about 24 feet of a 1/4 × 1/4 inch joint, about 48 feet of a 1/8 × 1/4 inch bead, and about 97 feet of a 1/8 × 1/8 inch bead. Wider or deeper joints use it much faster.
How many tubes of caulk do I need for 100 feet?
At 1/4 × 1/4 inch, 100 feet is 75 cubic inches, or 83 with 10% waste — 5 tubes of 10.1 fl oz. At 1/8 inch it is 2 tubes.
How much caulk for a bathtub?
A standard 60 inch tub against three walls is about 12 feet of corner bead. A 1/4 inch fillet uses 0.03125 sq in per inch, so the job takes about 4.5 cubic inches — well under one 10.1 fl oz tube, or one small squeeze tube.
How deep should caulk be?
For joints up to about 1/2 inch, fill the gap; for wider joints aim for a depth about half the width, at least 1/4 inch, over backer rod (ASTM C1193 guidance). Too deep a bead wastes caulk and cracks when the joint moves.
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Tubes to buy
5 × 10.1 fl oz