Coming to the App Store · iPhone
Adds fractions the way you read a tape.
A construction calculator for feet, inches and fractions, exact to 1/64″. $19.99 once. No subscription.
01 · Calculator
Type it the way you say it.
Feet, inches and the fraction each have a key. Results come back in feet-inch-fraction, decimal feet or metric, rounded to the precision you pick and marked when they are.
- 12
- ft′
- 7
- in″
- 3
- /8
- +
- 4
- ft′
- 11
- in″
- 15
- /16
- =
12′ 7 3/8″ + 4′ 11 15/16″ =
17′ 7 5/16″
02 · Tools
Fourteen calculators for the job.
Every answer shows the formula it came from. A few, with the numbers you would get:
| Tool | You enter | You get |
|---|---|---|
| Stairs | 9′ total rise | 14 risers at 7 11/16″, stringer 14′ 1″, plus IRC limit checks |
| Rafters | 24′ span, 6/12, 12″ overhang | 14′ 5 9/16″ rafter, plus hip and valley |
| Concrete | 10′ × 10′ slab, 4″ thick, 10% extra | 1.36 cu yd, or 62 bags at 80 lb |
| Layout | 12′ wall, studs 16″ on center | 10 studs and every mark from the end |
| Square | 12′ × 16′, diagonal measured 20′ 1/4″ | Out of square by 1/4″ |
| Board feet | 10 × 2×4×8′ and 4 × 2×10×16′ | 160 board feet |
Also drywall, roofing, flooring and tile, paint, deck boards, gravel and mulch, balusters and arcs. On iPhones with ARKit, measure a length with the camera and drop it into any field.
03 · Price
Free, or $19.99 once.
Free
- The fraction calculator
- Length, area and volume conversions
- Your last 20 calculations
Pro $19.99
- All 14 tools and camera measuring
- Unlimited history and saved projects
- PDF and CSV export
One in-app purchase, shared with your Family Sharing group and restored on any iPhone signed in to your Apple Account. Price shown in US dollars; the App Store shows your local price.
Data Not Collected.
No account, no ads, no analytics. Tape, projects and settings stay on your iPhone. Privacy policy
04 · Support
Questions
Email support@northwrightlabs.com with your iPhone model, iOS version and what you typed.
How do I type 12′ 7 3/8″?
Tap 1 2, ft′, 7, in″, 3, then /8. A number with no unit after feet is read as inches.
What do ≈▲ and ≈▼ mean?
The answer was rounded to your fraction precision. ▲ means the shown value is a little longer than the exact one, ▼ a little shorter. Change precision and rounding direction in Settings.
How do I get Pro on another iPhone?
Open Settings and tap Restore purchases while signed in to the same Apple Account. Members of your Family Sharing group get Pro too.
Do the stair checks follow my local code?
No. They are typical limits from the International Residential Code. Check the code your jurisdiction has adopted.
How accurate is camera measuring?
It is an estimate, usually within about a centimetre and better on iPhones with LiDAR. Check critical cuts with a tape.