Construction calculator
Add, subtract, multiply, and divide feet, inches, fractions, decimals, and metric values. Convert the result without retyping.
Construction math, retooled
Construction calculator.
Built for the jobsite.
Exact math for feet, inches, fractions, rafters, spacing, plan scale, materials, and real project costs. Works offline.
- Exact fractions
- Works offline
- Available now · iPhone & iPad
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FEET + INCHES ◆ RAFTERS ◆ EQUAL SPACING ◆ PLAN SCALE ◆ COSTED ESTIMATES ◆ JOB REPORTS ◆
One toolbox.
Zero guesswork.
Every tool follows the same clean input → answer → save flow, so the app stays quick even when the job gets complicated.
Stairs + rafters
Layout stairs, common rafters, pitch, rise, run, and cut lengths with diagrams that explain the answer.
Equal spacing
Set balusters, joists, posts, or panels evenly by count or target spacing, with exact marks.
Plan scale
Translate drawing measurements into full-size dimensions across architectural and engineering scales.
Materials + costs
Estimate concrete, flooring, drywall, paint, tile, and lumber with waste, unit costs, tax, and labor included.
Jobs + PDF reports
Keep calculations attached to the right project, then create a clean report for clients, crews, or your own records.
Field test
Mixed units in.
Clean answers out.
Tap a real-world calculation to see how Onsite Math keeps feet, inches, and fractions readable.
FIELD CALCREADY
ADD TWO CUTS
12′ 7⅜″ + 8′ 11¾″
21′ 7⅛″
6.581 m
From rough number
to ready report.
-
01INPUT → ANSWER
Calculate
Use construction-first inputs and see the exact answer immediately.
-
02QUANTITY → TOTAL
Estimate
Add waste, tax, labor, and local rates while the assumptions stay visible.
-
03JOB → REPORT
Save + share
Organize results by job and export a professional PDF when it is time to hand off.
Your numbers stay
on your device.
Onsite Math works offline, needs no account, contains no ads, and does not use third-party analytics. Job data remains yours.
Read the plain-language privacy policy →
ENGINE VERIFICATION
38,793
automated calculation checks passed
Speaks your language.
Measures your way.
Use imperial, metric, or both. Onsite Math ships in 11 languages from day one.
- English
- Spanish
- French
- German
- Italian
- Portuguese
- Polish
- Turkish
- Arabic
- Hindi
- Chinese
Start with your own measurements.
The fraction calculator and unit converter stay free. Try each Pro tool once with your own numbers before choosing a plan.
What does Onsite Math Pro include?+
Unlimited use of the Pro trade tools, plus jobs, material lists and PDF reports. Choose a monthly or yearly subscription, or a one-time Lifetime purchase. Prices and availability are shown in your App Store before confirmation.
How do I manage a subscription?+
Monthly and yearly plans renew automatically until cancelled in your Apple Account subscription settings. Lifetime does not renew; buying it does not automatically cancel an existing subscription. Restore purchases with the Apple Account used to buy Pro.
Good questions.
Straight answers.
Does it work without internet?+
Yes. Calculators, jobs, estimates, and reports are designed to work offline. Internet is only needed for Apple services or when you choose to share something.
Can I organize multiple jobs?+
Yes. Save calculations and estimates under the right job, then return to the work without rebuilding your inputs.
Does it support metric and imperial?+
Yes. You can calculate in feet, inches, fractions, decimal units, and metric, then convert results without starting over.
Can I use it for quotes?+
Costed estimates include materials, waste, labor, tax, and unit costs. Always review quantities and local requirements before issuing a commercial quote.
Will my project data be uploaded?+
No. Onsite Math stores job data locally and has no account system or third-party analytics. See the privacy policy for details.
Work through a construction calculation
Choosing your field calculator
Best construction calculator app for iPhone? Choose by the job