Add 12' 6-1/2" + 8' 9-3/4" as you measured it. Answers snap to 1/16" on a tape and show the rounding error. Area, volume, metric and a calculation tape. Works offline.Inchmark is a construction calculator that works in feet, inches and fractions, just the way you measure. Built for carpenters, finish work, cabinet makers and DIY, it takes the decimal conversions and miscuts out of the job.
[Type it like you read it]
Press 12, FEET, 6, INCH, 1 / 2 and you get 12' 6-1/2". Feet keys are blue, inches green, fractions orange. Add, subtract, multiply and divide, including finding the center with ÷2.
[Read the answer off the tape]
Answers are rounded to 1/16" and marked in red on a tape measure. When an answer is rounded you see the error, like −1/48", so you know exactly how close it is. Choose nearest, round up or round down.
[Area and volume]
Feet times feet gives square feet; multiply by a thickness for cubic feet and cubic yards. Metric values are shown underneath.
[Switch units]
Tap the answer to see it in inches and fractions, decimal feet or inches, yards, meters, centimeters or millimeters.
[Calculation tape]
Every answer you get with = is saved to the tape. Tap one to use it in your next calculation. Memory keys (M+ M− MR MC) are included.
[Made for the jobsite]
Big keys, key vibration and a left-handed layout. Works offline with no account. No ads on the calculator screen.
[Premium, buy once]
Seven jobsite tools (stairs, rafters, right angle and pitch, even spacing, area and concrete, board feet, circles and arcs), 1/32" and 1/64" precision, the full tape with notes and CSV export, night and high-contrast themes, and no ads. Not a subscription: buy it once and it's yours.
Stair checks use common IRC guidelines. Always check your local building code.
Exact fractions, tape answers