Caulk Calculator
Running out of caulk mid-bead is annoying, and buying too much wastes money on tubes that dry out. This calculator figures out exactly how many tubes you need based on your total joint length, gap width, and gap depth. It handles standard cartridges, squeeze tubes, and sausage packs.
A standard 10.3 oz caulk cartridge contains about 18.6 cubic inches of material. How far that goes depends entirely on the joint size. A narrow 1/4" x 1/4" joint gets about 297 linear feet per tube. A wider 1/2" x 1/2" joint only gets about 74 feet. Double the width and depth, and you use four times as much caulk.
For joints deeper than 1/2 inch, use a backer rod to fill the back of the joint before caulking. This saves caulk, improves adhesion (caulk bonds to two surfaces instead of three), and ensures proper cure depth. Most caulks should not be applied deeper than 1/2 inch in a single pass.
Different caulk types work for different applications. Silicone for bathrooms and exterior where flexibility matters. Acrylic latex for interior trim that will be painted. Polyurethane for concrete joints and high-movement exterior gaps. Butyl rubber for gutters and metal-to-metal joints.