# Tenon Tools

> Free construction calculators that state their formula and walk a verified worked example — and pay-once field apps (Tenon Calc, Tenon Cam, Tenon Log) in the works for iOS and Android. No ads, no subscriptions.

Every calculator page has a markdown mirror at the same URL with `.md` appended.

## Calculators

- [Concrete Slab Calculator](https://tenon.tools/calculators/concrete-slab.md): Concrete slab volume in cubic yards or cubic meters, plus 80 lb, 60 lb, or 25 kg bag counts — free, imperial + metric, with waste factor.
- [Rafter Length Calculator](https://tenon.tools/calculators/rafter-length.md): Common rafter length from run and roof pitch (rise-in-12 or degrees) — line length, rise, and plumb-cut angle. Free, imperial + metric.
- [Stair Layout Calculator](https://tenon.tools/calculators/stair-layout.md): Riser count, exact riser height, treads, and total run from floor-to-floor rise — with IRC and DIN 18065 comfort checks. Free, imperial + metric.

## Apps

- Tenon Calc — construction calculator with branded PDF quotes; pay once, own forever
- Tenon Cam — timestamp field camera; no ads, no vendor logo, your logo on the stamp
- Tenon Log — solo-crew site diary; one flat price for the whole crew

## Optional

- [llms-full.txt](https://tenon.tools/llms-full.txt): every calculator page inlined in full