Electrical, plumbing, HVAC, welding, masonry, carpentry, estimating & conversions — all code-compliant, all offline, all in your pocket.
33 calculators free forever · Early adopter pricing: $19.99 per trade · $49.99 for everything
Grouped by workflow, not alphabetically. Wire & conduit first, then service & load, then motors. The way your day goes.
Every calculation references the actual code book tables — not approximations. The same tables your inspector uses.
Table 9 impedance with AC skin effect. Table 310.16 ampacity. Chapter 9 conduit fill.
DFU tables, fixture units, water demand curves, drainage slope.
R311.7 headroom. R502 span tables. R802 rafters. Stair code.
D1.1 preheat tables. Carbon equivalent (CE & Pcm). Filler metal.
402.4 longest-length method. Residential low-pressure gas sizing.
NEC Table 9 impedance values — not the simplified DC resistance most apps use. Includes AC skin effect correction for conductors 2/0 AWG and larger, power factor input, and automatic pass/fail against NEC 210.19(A) and 215.2(A) thresholds.
Input total rise, and get riser height, tread depth, total run, stringer length, and the floor opening dimension for IRC R311.7.2 headroom clearance. A basic calculator would let you build stairs that fail inspection. This one catches the problem before you cut a stringer.
Pair a Bosch GLM 165-27CGL laser — shoot a distance and it drops into the active field. Total rise for stairs. Conduit run for voltage drop. Room length for drywall. No keypad. No walking back because you fat-fingered 147 instead of 174.
Connect an Owon OW18E multimeter after the wire is pulled — the app logs measured voltage alongside your calculated voltage drop. Calculated vs. actual, side by side, saved to the project. That's your proof for the inspector.
Type 12-5-1/8 and get 12' 5⅛" — parsed instantly in every input field. No switching modes, no separate calculator. The FIF engine handles architectural fractions, mixed formats, and converts seamlessly between decimal, feet-inch-fraction, and metric. It's the way you think on the jobsite.
10 welding calculators including AWS D1.1 preheat requirements, carbon equivalent (CE & Pcm), heat input, filler metal selection, and gas flow rates. Builder's Helper doesn't have it. Construction Master doesn't either. Nobody does.
Every calculation generates a branded PDF with inputs, step-by-step work, and code references. Attach them to estimates to show inspectors and clients exactly how you arrived at a number. Organize by project, export the full project report, or share individual calcs via AirDrop, text, or email.
Sync your projects across iPhone and iPad via iCloud. Your data stays in your private cloud — we never see it, we never ask for your email, and we never build a profile on you. The app works 100% in dead zones. When you get signal, iCloud syncs in the background. That's it.
Every calculator feeds the same system. Calculate, tap "Add to Project," pick the job — done. Every number you've ever run, organized by trade, under one job name. Come back in a week or a year. It's all there.
No "active project" to set. Run any calc, tap the button, pick the job from a list sorted by last used. Three taps.
Wire sizing files under Electrical. Concrete volume files under Masonry. You never tag, label, or sort anything.
Open a project from three months ago. Every wire size, every rafter length, every P/T reading — right where you left it.
Export any calculation as a branded PDF with inputs, work, and code references. Send it to your foreman, inspector, or GC.
33 calculators free. The rest at early adopter pricing. Your jobs, your calcs, your system.
Download on the App StoreQuestions? Feature requests? Join the Community Forum →
Masonry, welding, estimating, and conversions — free forever. No trial, no credit card, no bait-and-switch. When you're ready for more, pay once and own it.
An honest side-by-side against the two most popular construction calculator apps. They're good at what they do — here's where we overlap and where we go further.
| Feature | Contractor's Cheatsheet | Construction Master Pro | Builder's Helper MAX |
|---|---|---|---|
| Total calculators | 100+ | ~30+ (EZ Calcs + core) | 16 Quick-Jobs + calculator |
| Trades covered | 8 dedicated trades | Carpentry + electrical (5) + HVAC | Carpentry / GC |
| Technical Depth | |||
| Voltage drop math | NEC Table 9 AC impedance | Basic (simplified DC) | -- |
| Feet-inch-fraction input | Native in every field (FIF engine) | Primary feature | Included |
| Hidden in-app purchases | None — one price, all features | Upsells | Free + IAP |
| Electrical | |||
| Wire sizing (NEC 310.16) | Full NEC table lookup | -- | -- |
| Conduit fill (Chapter 9) | Multi-wire, all types | -- | -- |
| Voltage drop (Table 9 impedance) | AC impedance + verify | Basic (EZ Calc) | -- |
| Box fill / Service load / Motor FLC | Included | -- | -- |
| NEC code table references | Section-level citations | No code refs | No code refs |
| Plumbing | |||
| Pipe sizing (IPC) | Included | -- | -- |
| DFU count / Fixture units | Included | -- | -- |
| Gas line sizing / Drainage slope | Included | -- | -- |
| Welding | |||
| Preheat (AWS D1.1) | Included | -- | -- |
| Carbon equiv. / Heat input / Filler metal | Included | -- | -- |
| HVAC | |||
| Duct sizing (Huebscher) | Included | -- | -- |
| Refrigerant P/T chart (18 refrigerants) | Included | -- | -- |
| Superheat / Subcooling / Airflow ΔT | Included | Basic airflow (EZ Calc) | -- |
| Carpentry | |||
| Stair layout | + floor opening (IRC) | Full solution | Quick-Job |
| Rafter / Roof pitch | Included | Full solution | Quick-Job |
| Concrete / Block / Footing | + turn-down footings | Material estimation | Quick-Jobs |
| Drywall / Flooring / Decking | Included | Material estimation | Quick-Jobs |
| Crown miter / Board feet | Included | -- | Quick-Jobs |
| Joist span tables | Included | -- | -- |
| Wall framing / Painting / Fencing | Included | -- | Quick-Jobs |
| Masonry | |||
| Block count / Rebar / Mortar / Grout | Included | Block estimation | Block Quick-Job |
| General | |||
| Code compliance tables | NEC · IPC · IRC · AWS · IFGC | None | None |
| PDF reports with code refs | Branded PDF + code refs | Share / export | PDF export |
| Project notes / documents | Notes + dates | Notes + voice + photos + folders | Notes + docs + photos |
| Feet-inch-fraction math | Included | Primary feature | Included |
| Metric / Unit conversions | 8 converters | Comprehensive | Included |
| Works offline | 100% | Yes | Yes |
| Bluetooth tools | Bosch laser · Owon multimeter | Bosch GLM lasers | -- |
| Measured vs. calculated verification | Voltage drop verify | -- | -- |
| Pricing | $0–49.99 once (early adopter) | $20-36/yr subscription | Free + IAP |
| Cost after 3 years | $0–49.99 | $60-108 | ~$6 |
100% — every calculator, every code table, every conversion runs locally on your device. Use it in a basement, on a roof, in a tunnel. No signal required. When you get Wi-Fi, iCloud syncs your projects in the background.
NEC 2023 (with a 2020 toggle), IPC 2021, IRC 2021, AWS D1.1, and IFGC. Ampacity tables, impedance values, and conduit fill percentages come directly from the code books — not approximations.
Tap the Bluetooth icon on any input field, point your Bosch GLM laser and shoot. The measurement lands in feet-inch-fraction format, ready to calculate. Also supports Owon multimeters for voltage, current, and resistance. Measurements auto-log to your active project.
Every calculation generates a branded PDF showing inputs, step-by-step work, and code references. Share via AirDrop, text, email, or save to files. You can also export an entire project report with all calcs bundled.
No. There's no account, no email, no sign-up, and no tracking. Your data syncs through your existing iCloud — we never see it and never build a profile on you.
Masonry (11 calcs), Welding (11 calcs), Estimating (5 calcs), and Conversions (8 calcs) are free forever — no trial, no catch. The four pro trades — Electrical, Plumbing, HVAC, and Carpentry — are $19.99 each, or $49.99 for all. Buy them one at a time; you'll never pay more than $49.99 total.
Yes — current pricing is introductory. As we add more calculators, trades, and features, the price will increase. But if you buy now, you're locked in. Every future update and new calculator is yours at no additional cost. We think that's fair.
iOS first, Android is on the roadmap. The web version of the calculator engine is already built, so an Android release will follow once the iOS launch stabilizes.
Construction Master is a feet-inch-fraction calculator with basic dimensional math — and uses simplified DC resistance for voltage drop, which is inaccurate for large AC conductors. It has zero trade-specific calculators, no code compliance, no NEC tables, no pipe sizing, no welding, and charges $20–36/year. This app has 100+ calculators across 8 trades with NEC Table 9 AC impedance, IRC headroom checks, AWS preheat tables, and Bluetooth hardware integration — for one payment.
Report bugs, request features, share tips. Every post gets a real response from the person building this thing.
The only app that uses NEC Table 9 impedance values instead of simplified DC resistance.
17 calculators built around the NEC — wire sizing, conduit fill, voltage drop, service load, motor circuits. Every table your inspector references is already inside. Pair a Bosch GLM 165-27CGL laser and distances land in your calculator — conduit runs, raceway lengths, no keypad. Connect an Owon OW18E multimeter after the wire is pulled and the app logs measured voltage alongside your calculated drop — calculated vs. actual, side by side, saved to the project. Every calculation saves to your project.
Full access to all 15 electrical calculators.
Download for iOSOffset travel, pipe specs, fixture units, gas sizing — every plumber's daily math in one place.
13 calculators covering pipe layout, water supply, drainage, and gas. IPC/UPC tables built in. No more flipping through the Blue Book on the truck. Every calculation saves to your project.
Full access to all 13 plumbing calculators.
Download for iOSP/T charts for 18 refrigerants, superheat/subcooling, airflow Delta-T, temperature rise — every service call calc in one place.
10 calculators covering load sizing, duct design, refrigerant diagnostics, airflow analysis, and ventilation. Replaces 3–4 separate HVAC apps. Every calculation saves to your project.
The tab no other construction app has. Period.
10 welding calculators including AWS D1.1 preheat, carbon equivalent, heat input, filler metal selection, and cost estimation. Every calculation saves to your project.
No account required. No credit card. Just download and go.
Download for iOS26 calculators — more than any other construction app's entire library.
Framing, roofing, stairs, drywall, flooring, fencing, decking, insulation, paint, siding, tile, and reference tables. IRC span tables and code checks built in. Pair a Bosch GLM 165-27CGL and shoot a total rise, a room length, a rafter run — the number drops straight into the calculator. No typing. No transposing. Every calculation saves to your project.
Full access to all 26 carpentry calculators.
Download for iOSBlock count, concrete volume, rebar, mortar, grout, footings, and curing — one app.
11 calculators for masonry and concrete work. Stop doing bag math in your head on the jobsite. Every calculation saves to your project.
No account required. No credit card. Just download and go.
Download for iOSKnow your numbers before you bid. Markup, margin, labor burden, and material volume.
5 estimating calculators that help you price jobs correctly. Understand the difference between markup and margin. Know your true labor cost. Every calculation saves to your project.
No account required. No credit card. Just download and go.
Download for iOSFeet-inch-fraction math, unit conversions, and trade-specific lookups.
8 converters covering every unit you encounter on a jobsite. Feet-inch-fractions, metric, temperature, pressure, area, volume, trade units, and energy cost. Every conversion saves to your project.
No account required. No credit card. Just download and go.
Download for iOS