100+ code-compliant calculators across 8 trades. No subscription. No account. No ads. Pay once, own it forever — like every other tool on your truck.
Try everything free for 30 days · Then $29.99 $19.99 per trade · $49.99 $39.99 for all 8
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.
We don't have 30 years of brand recognition. What we have is a "Show work" button on 30 calculators that expands the full formula, your values substituted in, and step-by-step arithmetic with code section citations. Check us against your code book. We want you to.
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. Every result includes a "Show work" toggle that expands the full formula, substituted values, and step-by-step arithmetic. Hand it to your inspector.
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. Tap "Show work" to see every step — risers, run, Pythagorean stringer, Blondel comfort check — all with code references.
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, results, and the full "Show work" math breakdown — formula, substituted values, step-by-step arithmetic, and code references. Attach them to estimates. Hand them to inspectors. Organize by project, export full project reports, 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.
30 days free. Then own it. Every trade, every code table, every future update — one price.
Try free for 30 daysQuestions? Feature requests? dev@sampateklabs.com →
No credit card to start. No "forgot to cancel" gotcha. After 30 days, pay once and keep it forever. Like a tool, not a subscription.
An honest comparison against the apps tradespeople actually use. They've been around longer — here's what you get for the money.
| Feature | Contractor's Cheatsheet | ElectriCalc Pro | Construction Master Pro |
|---|---|---|---|
| Total calculators | 100+ | ~15 (electrical only) | ~30+ (carpentry focus) |
| Trades covered | 8 dedicated trades | Electrical only | Carpentry + 5 elec topics |
| Pricing model | One-time purchase | $36/yr subscription | $20–36/yr subscription |
| Cost after 3 years | $39.99 (one time) | $108 | $60–108 |
| Technical Depth | |||
| Shows full work + code citations | 30 calculators — formula, values, steps | Result only | Result only |
| Voltage drop (AC impedance) | NEC Table 9 with skin effect | Basic DC method | Basic (EZ Calc) |
| Feet-inch-fraction input | Native in every field | Included | Primary feature |
| Electrical | |||
| Wire sizing (NEC 310.16) | Full table + derating | Included | — |
| Conduit fill (Chapter 9) | Multi-wire, 7 conduit types | 12 conduit types | — |
| Box fill (NEC 314.16) | With 2020+ EGC rule | — | — |
| Residential service load | NEC 220 standard method | — | — |
| Panel schedule builder | Auto-balance + imbalance check | — | — |
| Motor FLC / EGC / GEC | Included | Included | — |
| Plumbing · Welding · HVAC | |||
| Pipe sizing / DFU / Gas line | IPC + UPC compliant | — | — |
| Welding (preheat, CE, heat input) | AWS D1.1 compliant | — | — |
| HVAC (superheat, duct, P/T) | R-410A, R-22, R-32, R-454B | — | — |
| MCA/MOP wire sizing (NEC 440) | Included | — | — |
| Carpentry · Masonry | |||
| Stair layout (IRC R311.7) | + floor opening + headroom | — | Full solution |
| Rafter / roof / joist span | Included | — | Full solution |
| Concrete / block / rebar | Included | — | Material estimation |
| Platform | |||
| Works offline | 100% | Yes | Yes |
| Bluetooth tools | Bosch laser + Owon multimeter | — | Bosch laser |
| Measured vs. calculated verify | VDrop compare + save to project | — | — |
| Project organization | Multi-trade projects + PDF export | — | Notes + folders |
| Account / email required | None | Apple ID purchase | Apple ID purchase |
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.
Everything is free for 30 days — all 100+ calculators, all 8 trades, Bluetooth, PDF export, everything. No credit card required. After the trial, unlock trades individually at $19.99 each or get everything for $39.99. One payment. No subscription.
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.
Every calculation shows its full work and cites the specific code section — NEC Table 310.16, IPC Appendix E, IRC R311.7, AWS D1.1. We don't just give you a number; we show you how we got it, which table we used, and what the code says. Check us against your code book — we're designed for that. The underlying math engine has been verified against 300+ test cases covering known-answer scenarios, boundary conditions, and edge cases across every calculator.
An engineer who saw the tools tradespeople depend on get turned into subscription cash grabs. ElectriCalc Pro went from a $10 purchase to $36/year. Construction Master did the same. The trades deserve better tools at a fair price, and the people using them should have a say in what gets built next. Feature requests go directly to the developer — no ticket system, no corporate filter.
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.
ElectriCalc Pro covers electrical only and charges $36/year — in 3 years you've spent $108 for one trade. Construction Master is a dimensional math calculator with no code compliance and no trade-specific tools. This app covers 8 trades with NEC Table 9 AC impedance, IRC headroom checks, IPC pipe sizing, AWS preheat tables, HVAC superheat/subcooling, and Bluetooth hardware integration — for a single payment of $39.99. And every result shows the full work and code citation, which neither competitor does.
Report bugs, request features, share tips. Every post gets a real response from the person building this thing.
Effective: March 2026 · Sampatek Labs LLC
The short version: We don't collect your data. We don't want it.
No accounts or personal information. Contractor's Cheatsheet does not require account creation, email addresses, phone numbers, or any personally identifiable information. There is no sign-up, no login, and no user profile.
No analytics or tracking. We do not use Google Analytics, Facebook Pixel, or any third-party tracking or advertising SDKs. We do not track your usage patterns, calculator inputs, or navigation behavior.
Your data stays on your device. All calculations, projects, and saved results are stored locally on your device and synced via your personal iCloud account (if enabled). We have no server infrastructure that receives, stores, or processes your calculation data. We cannot see your projects, your inputs, or your results.
iCloud sync. If you enable iCloud, your data syncs between your devices through Apple's infrastructure using your Apple ID. This sync is governed by Apple's privacy policy, not ours — because we are not involved in the process.
Bluetooth peripherals. If you connect a Bluetooth laser measure or multimeter, the app communicates directly with the device over Bluetooth Low Energy. No measurement data is transmitted to us or any third party.
Crash reports. If the app crashes, Apple may collect anonymized crash diagnostics per your device settings. We may receive aggregated, non-identifiable crash reports through App Store Connect to fix bugs. These contain no personal information or calculation data.
Changes. If we ever change this policy, we'll update this page and note the effective date. We will never retroactively weaken privacy protections.
Contact: dev@sampateklabs.com
Effective: March 2026 · Sampatek Labs LLC
What this app is. Contractor's Cheatsheet is a field reference and estimating tool for licensed tradespeople. It performs calculations based on published code tables (NEC, IPC, IRC, AWS, IFGC, ASHRAE) and standard trade formulas.
What this app is not. This app is not a substitute for engineered drawings, stamped calculations, licensed professional judgment, or the authority of your local code official (AHJ). It does not replace your code book.
For estimating and field reference only. All calculations are provided for estimating and field reference purposes. While we verify our formulas against published standards and maintain an automated test suite, we cannot guarantee that every result is correct for every jurisdiction, every code edition, or every field condition. You are responsible for verifying results against the currently adopted codes in your jurisdiction.
No liability. Sampatek Labs LLC provides this software "as is" without warranty of any kind. We are not liable for any damages arising from the use of calculation results, including but not limited to failed inspections, material waste, property damage, or personal injury. Use professional judgment.
Purchases. Purchases are one-time and processed through Apple's App Store. Refund requests are handled by Apple per their refund policy. We do not process payments directly.
Intellectual property. The app, its design, code, and content are the property of Sampatek Labs LLC. NEC®, IPC®, IRC®, and other code references are trademarks of their respective organizations. We reference these standards for interoperability; we are not affiliated with or endorsed by NFPA, ICC, AWS, or ASHRAE.
Contact: dev@sampateklabs.com
Found a bug? Think a formula is wrong? Have a feature request? We want to hear about it.
Email us directly
dev@sampateklabs.comWe read every email. If you're reporting a calculation error, include the inputs you used and the result you expected — we'll prioritize it.
In-app feedback. Tap the ≡ menu in the app, then "Send Feedback." You can rate your experience and describe the issue — it opens a pre-formatted email with your app version and device info included.
Response time. We're a small team. We typically respond within 24–48 hours on business days. Calculation accuracy reports get top priority.
FAQ. Check the frequently asked questions for answers to common questions about pricing, offline use, iCloud sync, and accuracy.
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.
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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