Sealant Calculator

What this calculator does

The sealant calculator estimates how much caulk or sealant is needed to fill a joint of a given length, width, and depth, and how many tubes or cartridges to buy.

The formula

The volume of sealant needed equals the joint’s length × width × depth, all in consistent units (this calculator converts joint length from feet to inches to match width and depth). One cubic inch equals about 0.55411 fluid ounces, giving the total volume needed in fluid ounces. Dividing that by the fluid-ounce capacity of your chosen tube or cartridge, and rounding up, gives the number of tubes to purchase.

• Standard caulk cartridges are commonly 10.1 fl oz, with larger quart-size cartridges around 29 fl oz for bulk gun applicators, and smaller 5.5 fl oz squeeze tubes for small jobs.
• Joint width and depth should generally be roughly equal for proper sealant flexibility — a common rule of thumb is depth about half the width for wider joints, using backer rod to control depth.

This tool is for general project planning; always check the sealant manufacturer’s coverage guidance for your specific product.