Best Trade Calculator Apps for iPhone — No Subscription Required (2026)
The Best Trade Calculator Apps That Don’t Charge Monthly
2025 was the year Calculated Industries moved their entire lineup to subscriptions: Construction Master Pro ($19.99/month), ElectriCalc Pro ($29.99/year), and Pipe Trades Pro (subscription). For tradespeople who’d been using these tools for years — some for decades — it felt like a betrayal.
The good news: alternatives exist for every trade, and most of them cost less than a single month of the Calculated Industries subscription.
This guide covers the best calculator apps by trade, with a focus on one-time purchase options. We built some of these apps ourselves, and we’ll be upfront about that — but we’ll also list competitors when they’re the better fit.
For Carpenters and Framers
What You Need
Stair rise and run (IRC code compliance), board feet, stud spacing and count, roof pitch, feet-inch-fraction math, and dimensional lumber calculations.
Best Option: FieldLab Framing & Carpentry Calculator — $9.99
Covers stair calculations with IRC compliance checking, board feet, stud spacing, roof pitch, and lumber math. Native SwiftUI with dark mode support. Works offline.
We built this app. It doesn’t yet include compound miter angles or rafter calculations — those are on the roadmap. If those are critical for your work today, consider BuildCalc below.
Runner-Up: BuildCalc — $24.99
One-time purchase with stair, rafter, feet-inch math, and general construction calculations. Dated UI but functional. The stair calculator has devotees who’ve used it for decades.
Avoid: Construction Master Pro — $19.99/month
Still a good calculator, but at $240/year for what used to cost $25, the value proposition is gone. If you already own it from a prior purchase, keep using it. Don’t buy in new at subscription pricing.
For Electricians
What You Need
Voltage drop, wire sizing (NEC Tables 310.16/310.17), conduit fill, Ohm’s law, and ideally both NEC 2023 and NEC 2026 tables.
Best Option: FieldLab Electrician NEC Calculator — $9.99
Voltage drop for single-phase and three-phase circuits, wire sizing with derating factors, Ohm’s law, and conduit fill. Ships with NEC 2023 and NEC 2026 bundled. Dark mode by default — critical for working in panels.
We built this app. It covers the core daily calculations. Motor calculations and service entrance sizing are on the roadmap.
Alternative: Electrical Calc Elite — $19.99 + NEC Add-On
One-time purchase for the base app, but NEC 2023 tables cost extra. Functional but dated UI (circa 2015). No dark mode.
Avoid Paying Subscription: ElectriCalc Pro — $29.99/year
Solid app, but the subscription is hard to justify for calculation formulas that haven’t fundamentally changed.
Free Option: BuiltByFieldLab.com Web Calculators
For quick field checks, our voltage drop, Ohm’s law, and wire size calculators run free in your browser with no account.
For Pipefitters and Steamfitters
What You Need
Pipe offset calculations (standard and rolling), pipe data reference (OD, ID, weight per foot), and ideally Victaulic groove dimensions.
Best Option: FieldLab Pipefitter Calculator — $9.99
Standard and rolling offsets with visual geometry diagrams, pipe data reference, and Victaulic coupling support. Every calculation shows a scaled diagram so you can visually confirm the offset matches your layout.
We built this app.
Avoid Paying Subscription: Pipe Trades Pro
Well-regarded tool (4.8 stars, 3,800 ratings) but now on a subscription model. No visual diagrams — numbers only.
Free Option: BuiltByFieldLab.com Pipe Offset Calculator
Our pipe offset calculator handles standard offsets at 90°, 45°, 22.5°, and 11.25° with visual output. Free, no download.
For Structural and Span Calculations
What You Need
Joist and rafter span lookups per NDS/AWC tables, load calculations, and lumber grade comparisons.
Best Option: FieldLab Structural Span Calculator — $7.99
Span lookups using AWC/NDS data, with species and grade comparisons. Calculates allowable spans based on load, spacing, and lumber grade.
We built this app.
The Broken Official App: AWC Span Calc — Free but 2.9 Stars
The American Wood Council’s official Span Calc app is free, which would make it the obvious choice — except it’s rated 2.9 stars with only 15 reviews. Users report dropdowns that stop working after updates and the app locking up after iOS upgrades. At 176MB for what should be a lightweight reference tool, something went wrong in development.
The Full Comparison Table
| App | Trade | Price | Subscription | Rating | Dark Mode | Offline |
|---|---|---|---|---|---|---|
| FieldLab Framing & Carpentry | Carpenters | $9.99 | No | New | Yes | Yes |
| FieldLab Electrician NEC | Electricians | $9.99 | No | New | Yes | Yes |
| FieldLab Pipefitter | Pipefitters | $9.99 | No | New | Yes | Yes |
| FieldLab Structural Span | Structural | $7.99 | No | New | Yes | Yes |
| Construction Master Pro | Carpenters | $19.99/mo | Yes | 4.9 | No | Yes |
| ElectriCalc Pro | Electricians | $29.99/yr | Yes | 4.9 | No | Yes |
| Pipe Trades Pro | Pipefitters | Subscription | Yes | 4.8 | No | Yes |
| BuildCalc | Carpenters | $24.99 | No | 4.7 | No | Yes |
| Electrical Calc Elite | Electricians | $19.99+ | No | 4.8 | No | Yes |
| AWC Span Calc | Structural | Free | No | 2.9 | No | Yes |
Frequently Asked Questions
Why are all these apps moving to subscriptions?
Calculated Industries likely moved to subscriptions because one-time purchase revenue is unpredictable and investor/private equity pressure favors recurring revenue models. The underlying calculations haven’t changed — the math for voltage drop and pipe offsets is the same as it was 20 years ago.
Are the FieldLab apps really $9.99 forever?
Yes. One-time purchase, no subscription, no in-app purchases for core features. NEC code updates are included. We believe trade tools should be buy-once tools.
The FieldLab apps are new and have no ratings. Why should I trust them?
Fair point. The apps are new. You can verify the calculation accuracy yourself using our free web calculators — they use the same underlying formulas. Try the voltage drop calculator or stair calculator and check the results against your own known-good calculations. If the math is right on the web, it’s right in the app.
Can I use these on Android?
The FieldLab apps are currently iOS only. The free web calculators at BuiltByFieldLab.com work on any device with a browser — including Android phones, tablets, and desktop computers.