How to Use the Silicone Caulk Calculator
Not sure how many cartridges to grab before caulking a bathroom or kitchen? This calculator takes your total joint length (ft) and bead width, then tells you how far a standard 10.1 fl oz silicone caulk cartridge stretches and how many cartridges you'll need.
Assuming a triangular bead cross-section (width² ÷ 2), the formula is: coverage per cartridge (ft) = 18.23 in³ ÷ (bead width in² ÷ 2) ÷ 12. For example, at a 1/4 in bead width, one cartridge covers roughly 48.6 ft — so a 25 ft job needs just one cartridge.
Bead width should match the width of the joint you're filling. Narrow tile grout lines typically use 1/8 in, sinks and countertop edges use around 1/4 in, tub surrounds often need 3/8 in, and wider gaps like window frames call for 1/2 in. Note how sharply coverage drops as bead width increases — a wider bead uses far more material per foot.
Frequently Asked Questions
Match it to the width of the joint, or go slightly larger. Tile grout lines and sink edges typically use 1/8-1/4 in, while tubs or window frames with wider gaps often need 3/8-1/2 in.
Yes, it's a good idea to buy one extra cartridge to account for leftover material at the end of a tube and unavoidable application waste.