Answers to the questions that come up before a purchase. Technical explanations of the individual calculations are shown below each calculator.
Price and billing
What does it cost?
All 104 calculators are free to use, without an account and without a time limit. You only pay for the export: the verification PDF and export files such as the cam contour for CAD import in the cam disc calculator. See pricing →
One-time purchase or subscription?
The one-time purchase unlocks the export for exactly one calculator, permanently. The subscription unlocks it for all calculators as long as it runs. If you need one specific verification, buy it once; if you work with different calculators regularly, the subscription is the better fit.
Do I get an invoice?
Yes. Payment is handled by Paddle as merchant of record, and Paddle issues the invoice with VAT shown separately. Businesses can enter their VAT identification number during checkout.
How do I cancel the subscription?
Any time, with no notice period. Management runs through Paddle; you will find the link in every payment confirmation. The export stays unlocked until the end of the period you already paid for.
Verification PDF and export files
May I pass the verification PDF and the export files on?
Yes. The generated PDF and the export files are yours: you may hand them to clients and manufacturers, file them in project records and include them in quotations or documentation.
What is in the verification PDF?
All inputs, the results, the formulas used with their source, and the charts of the calculation. Plus fields for project, part and engineer, so the document fits into a file without rework.
Account and data
Do I need an account?
Not for calculating. You only need an account to save calculations or to generate a verification PDF and export files.
Why is there no password?
You receive a sign-in link by email instead, valid for 60 minutes. That saves you another password, and a password that does not exist cannot be stolen.
What happens to my inputs?
Calculations run in your browser, on your device. Your inputs are only transmitted when you save a project or generate a document. Privacy policy →
Can I delete my account?
Yes, at any time and without asking: in your account, using the delete button. This removes the account, the saved projects and the sign-in data.
How the calculation methods are verified is described on the methodology page. If your question is not covered here, write to me. Methodology → · Contact →