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Free feet-inch-fraction calculator
Add, subtract, multiply and divide feet, inches and fractions — exactly. Then tap Unit on any answer to convert to decimal feet, inches, yards, mm, cm or metres. Same engine as the app; runs right here, no sign-in.
0
PitchSlope
Rise
Run
Diag
Hip/ValIrr
JackIrr
StairsRiser
StudsO.C.
Bd Ft
Conv
MR
M+
M−
MC
Unit
Feet→ft
Inch→in
/
⌫
÷
7
8
9
C
×
4
5
6
AC
−
1
2
3
%x²
+
0
.
=
Type on your keyboard too: digits, + − × ÷, Feet, Inch, / for fractions, Unit to convert, Enter for =.
The same math, on your tape measure — offline.
Rafters, stairs, studs, board feet, pitch and a paperless tape, in the key layout your thumbs know. $9.99 once, no subscription.
How to use it
Punch it like the calculator on your belt
Enter a dimension the way you'd say it:
• Feet ÷ a number splits a run into equal parts:
• Length × length gives area (sq ft); × a third length gives volume (cu ft).
• Unit cycles the answer through decimal feet, inches, yards, metres, cm and mm.
• The grey trade keys up top — rafters, stairs, studs, pitch — live in the iOS app.
12 Feet 6 Inch 3 / 16 gives 12' 6-3/16". Then an operator, the next dimension, and =.• Feet ÷ a number splits a run into equal parts:
12' 6-3/16" ÷ 3 = 4' 2-1/16" — exact, never 4.177.• Length × length gives area (sq ft); × a third length gives volume (cu ft).
• Unit cycles the answer through decimal feet, inches, yards, metres, cm and mm.
• The grey trade keys up top — rafters, stairs, studs, pitch — live in the iOS app.
Quick conversions
Popular lookups
The same math, offline
Every calc, on your tape measure — even with no signal.
TapeMath for iPhone runs this exact engine offline, adds rafters, stairs, studs, pitch and a paperless tape, and the key layout your thumbs already know. $9.99 once — no subscription, ever.
See the appComing soon — TapeMath is in final App Review. Meanwhile, use the free web calculator →