Support & Contact

How to reach us

Email is the only channel, and it is answered by the person who wrote the code. There is no phone line and no live chat: a one-person project that pretended to have either would be lying about the response you can expect.

Include the page URL and, if you are reporting a wrong number, the exact inputs. A screenshot is nice; the numbers are what actually matters.

• Email: to be published
• Typical response time: one person answers this mailbox, so expect a few working days rather than the same day. Nothing here is on a support rota.
• Languages: English and German

Reporting a calculation you think is wrong

This is the report we most want to receive, and it goes to the front of the queue. Every calculator on this site is backed by a set of test vectors — fixed inputs with known-correct outputs, checked against published worked examples — and a report that survives review becomes a new vector, so the same mistake cannot come back later.

Tell us the calculator, the exact inputs including units, the result you got and the result you expected, and where your expected figure comes from if it is from a table or a code reference. If the report holds up, the fix ships and the vector stays.

Worth naming up front: the calculators state their assumptions on the page, and disagreement about an assumption is not the same as an error. Bag yield and waste factor are yours to set for exactly that reason, and each calculator's rounding rule is stated in its worked method on the page rather than buried in the engine.

The waitlist

If you signed up to hear when an app ships, every email we send carries an unsubscribe link and it takes effect immediately. You do not need to write to us to leave.

Signing up is double opt-in: if you never received the confirmation email, nothing was ever added and nothing further will be sent. Check the spam folder first — a confirmation from a small sender is the classic casualty — and if it genuinely never arrived, send us the address and we will look at the delivery log.

Privacy requests

Access, correction, deletion, a portable copy, or withdrawing consent: write to the email above and say which one you want. Most of it you can do yourself in seconds — the unsubscribe link removes your address, the "Cookie settings" link in the footer switches analytics off, and clearing site data in your browser erases everything stored on your device.

What is collected, and on what basis, is set out in full on the privacy page rather than summarised here.

Purchases, refunds and restoring an app

This is worth knowing before you need it, because for most of it we are not the ones you contact.

Purchases go through the App Store and Google Play. They take the payment, they issue the receipt, and they handle refunds under their own policies — Tenon Tools never sees a card number and cannot refund a purchase on your behalf. Restoring a purchase on a new device is a store function too, and it works because the unlock is tied to your store account rather than to an account with us.

There are no subscriptions to cancel. Every app is a single payment that does not renew, so there is no billing to stop and nothing that lapses if you stop paying attention to it.

Security reports

If you find something that looks like a security problem — in the site, in the waitlist form, or later in an app — email it rather than posting it publicly, and you will get an acknowledgement and a fix timeline. There is no bug bounty; there is a small project that would rather know.