Why FieldLab Will Never Charge a Subscription
A Calculator Is Not a Service
When Construction Master Pro moved to $19.99/month in 2025, the App Store reviews told the story. Journeymen who’d recommended the app to every apprentice for a decade stopped recommending it. The tool didn’t change — the invoice did.
We watched this happen and decided to build the opposite: trade calculators that you buy once and own forever.
The Math on Subscriptions
A $20/month subscription costs $240/year. Over a 30-year career, that’s $7,200 for a calculator. Over a 44-year career (apprenticeship at 18 to retirement at 62), it’s $10,560.
For what? The voltage drop formula is the same formula it was in 1990. Pipe offset trigonometry doesn’t receive monthly feature updates. Stair rise and run calculations aren’t evolving. The underlying math is stable — it’s the business model that keeps changing.
Why Software Companies Push Subscriptions
We understand the business logic. One-time purchases create unpredictable revenue. Investors value recurring revenue at higher multiples. When a private equity firm acquires an app company, subscription conversion is often the first move.
For productivity tools with genuinely evolving features — cloud collaboration, AI-powered assistance, real-time data feeds — subscriptions can be fair. But a calculator doesn’t collaborate with anyone. It doesn’t need cloud servers. It computes a formula and shows you the answer.
Our Pricing Commitment
Every FieldLab calculator is a one-time purchase:
- Framing & Carpentry Calculator: $9.99
- Electrician NEC Calculator: $9.99
- Pipefitter Calculator: $9.99
- Structural Span Calculator: $7.99
NEC code updates are included. When a new code edition is adopted by your state, the app updates through the standard App Store mechanism — no additional charge.
No trial periods. No account creation. No internet requirement. You download it, it works, it’s yours.
How We Sustain This
A reasonable question: if you don’t charge recurring fees, how do you keep the lights on?
Our costs are low. FieldLab is a small operation, not a venture-backed startup. We don’t have a sales team, a marketing department, or office space. The apps are built with modern, maintainable code (SwiftUI) that makes iOS compatibility updates straightforward. And the trade calculator market is large enough that one-time purchases at fair prices sustain the business.
We also run BuiltByFieldLab.com — this website — which provides free calculators, how-to guides, and gear reviews. The gear reviews include Amazon affiliate links that generate a small commission on purchases. This diversified approach means the apps don’t need to carry the entire business.
What About NEC Code Updates?
The NEC updates on a roughly three-year cycle (2020, 2023, 2026). When a new edition drops, we update the app’s tables and push it as a free update through the App Store. You don’t pay extra for NEC 2026 support — it’s part of the $9.99 purchase.
Calculated Industries charges for NEC updates as separate purchases or folds them into the subscription cost. We think that’s the wrong approach for a tool that references public safety codes.
The Trade Tool Standard
A framing hammer doesn’t charge you per nail. A tape measure doesn’t require a monthly plan. A speed square doesn’t expire after 30 days.
Trade tools are bought, owned, and used until they wear out or something better comes along. We think software trade tools should work the same way.
That’s the commitment. No subscriptions. No in-app purchases for core features. Buy it, own it, use it.