The calculator is free.
Pay when you issue a report.
Everything that involves calculation, sharing links, and reviewing results is free — forever. Issuing a watermark-free engineering deliverable costs $5 per report, or $20/month for unlimited reports on Engineer Pro.
The calculator, every check, the on-screen report, and shareable links. Built for iteration.
- Full calculator — all methodologies (Mechanics, BTH-1, EC3, DNV)
- Live schematic, governing check, assumptions, warnings
- Full on-screen report with PREVIEW watermark
- Shareable configuration links
One engineering deliverable. Unlocks the current configuration plus 72 hours of revisions.
- Watermark-free report, ready to print or save as PDF
- 72-hour revision window — tweak inputs without paying again
- Purchase appears on your Account page for re-download
- Scope disclaimers stay on the report — not a substitute for FEA
For consultants and in-house engineers who issue lug reports regularly.
- Unlimited watermark-free reports
- Engineer profile + stamp auto-applied to every report
- Saved report history on your Account
- Cancel anytime via the Stripe Billing Portal
A deliverable, not a calculation.
The calculation engine is free because the value is in the deliverable: a traceable, watermark-free document you can hand to a reviewer or a client. We don't meter calculation, don't sell your data, and don't bury the scope disclaimers. Paying removes the preview watermark — it does not make this a substitute for FEA or detailed engineering review.
Engineers iterate. So does the unlock.
A single-report purchase unlocks your configuration and any revisions to it for the next 72 hours. Tweak the plate width, re-check the weld, re-print — same purchase covers it. After 72 hours the lock returns and a new deliverable is a new purchase.