Free Construction & Renovation Calculators

No sign-up, no email, nothing to install. Enter your measurements, get the numbers you need, and check them against the building code before you spend money on materials.

• Stair Stringer Calculator
  Riser height, tread depth, stringer length, cut angle and throat depth — with an IRC code check.
• Deck Board Calculator
  How many deck boards to buy, linear feet, joists and screws — with a check against the IRC decking spans.

Why these are free

Because they cost almost nothing to run. Every calculator on this site runs entirely in your browser — nothing is sent to a server, nothing is stored, and there is no account to create. The site is supported by advertising.

About the numbers

Each calculator gives you the working numbers and then checks them against the relevant part of the International Residential Code, so you can see at a glance whether your layout is legal before you cut anything. Codes vary by state and county, so always confirm with your local building department before starting work.