Feet & inches calculator
Add, subtract, multiply and divide in feet, inches and fractions — enter 12 ft 6-3/8 in like you measure it. The fastest inches feet calculator for carpenters and framers.
The construction calculator & carpentry calculator built for real job-site math
HammerCalc is the best construction calculator app for mixing feet, inches & fractions with metric & imperial in one tap — plus visual tools for stairs, square footage, rafters, roofs, and more on iPhone, iPad & Mac.
Calculator tools
Every construction calculator you reach for on site
One subscription. Every Apple device. No data collected.
Metric & imperial calculator
Combine millimeters, meters, feet and inches in a single equation. The metric imperial calculator tradespeople actually need — no unit converter app required.
Fraction calculator for construction
Tap fractions off a ruler with the Tape Measure widget. Round to 1/16″, 1/32″ or 1/64″. Faster than typing on any standard construction calculator.
Stairs calculator
Interactive stair calculator with live diagrams — rise, run, stringer length and headroom update as you drag sliders. Layout stairs with confidence.
Square foot calculator
Calculate area and square footage for rooms, slabs and layouts. Visual square footage calculator built for estimators, tile setters and general contractors.
Rafter calculator
Common and hip rafter math with interactive diagrams. A proper rafter calculator and framing calculator for roof carpenters — not just a lookup table.
Roof pitch calculator
Pitch, slope and rafter length from a visual roof model. The roof calculator you want when you're on a ladder checking numbers.
Drywall calculator
Sheet counts and layout from wall dimensions. A dedicated drywall calculator that saves time on every hang and finish bid.
Circle & arc layout
Full circles, arcs and curves with visual guides — for columns, decks, trim and any radius layout on site.
Triangle & polygon calculator
Irregular shapes, angles and side lengths with diagrams that update as you work. Essential for complex carpentry calculator layouts.
Built-in plan viewer
Open PDFs and photos without leaving the app. HammerCalc remembers page, zoom and position — your contractor calculator app and plan room in one.
Notes with calc history
Save any result into a project note with timestamps. Full history so you never lose a critical measurement between the truck and the cut.
Why builders call HammerCalc the best construction calculator
Whether you search for a construction calculator, carpentry calculator, best construction calculator app, stair calculator, square foot calculator, feet and inches calculator, or metric imperial calculator — HammerCalc replaces a drawer full of single-purpose apps with one fast, modern tool. Built for Apple. Private by design. Try it free for 7 days.
FAQ
Construction calculator questions
What is the best construction calculator app for iPhone?
HammerCalc is designed for tradespeople who need feet, inches, fractions and metric in one equation, with pro tools for stairs, square footage, rafters and roofs — on iPhone, iPad and Mac with one subscription.
Can I use HammerCalc as a carpentry calculator?
Yes. Carpenters use HammerCalc for framing math, stair layout, rafter cuts, area calculations, and everyday feet-inch-fraction arithmetic with the Tape Measure widget.
Does it work as a metric and imperial calculator?
Yes. Enter feet, inches, millimeters and meters in the same equation. Convert the answer to any unit with one tap — ideal when plans mix units.
How much does HammerCalc cost?
7-day free trial, then $3.99/month or $24.99/year. One subscription covers all your Apple devices. Learn more about HammerCalc.
Get the best construction calculator on your iPhone, iPad & Mac
Stairs, square foot, feet & inches, metric & imperial — try HammerCalc free for 7 days.
Download on the App Store