Frequently asked questions

All 106 calculators are free to use, without an account and without a time limit. 103 of them produce a verification PDF, and for 17 that PDF is free as well. For the others you pay for the export: the verification PDF and export files such as the cam contour for CAD import (Cam design calculator). See pricing →

The single purchase is a one-off payment with no subscription: it unlocks exactly one calculator, with unlimited exports, and it does not buy a single document. For that calculator we guarantee at least 36 months of operation from the date of purchase; after that it keeps running for as long as we operate the website. The annual subscription unlocks every calculator for as long as it runs. If you work with one particular calculator regularly, buy it once; if you keep switching between calculators, the subscription is the better fit.

The calculators with the scope of specialist software, for example Cam design, Spur gear geometry, and MSA carry a higher one-off price. Each of them replaces a whole package of work rather than a single formula - work that would otherwise call for specialist software or a day by hand. The annual subscription includes them at no extra charge. Which calculator carries which price is stated on the pricing page and at the calculator itself. See pricing →

These calculators output files of their own, and different ones at that: Cam design: cam contour as XYZ points (SolidWorks, Excel, CSV); Spur gear geometry: tooth contour of both gears (DXF, Excel, CSV); Kinematics Studio: mechanism drawing (DXF), value table over the cycle (Excel, CSV), cam contour as XYZ points (SolidWorks, Excel, CSV), and animation of the cycle (WebM). All of them without watermark and without copy protection, the DXF in version R2000. What the DXF holds depends on the calculator - for the spur gear the tooth contour, for the linkage studio the whole drawing of the mechanism on separate layers. Every other calculator delivers the verification PDF. A higher price therefore does not mean there are export files: the price and the kind of output are two different things.

Yes. Payment is handled by Paddle as merchant of record, and the invoice comes from there. You enter the company name and the VAT identification number in the checkout window yourself: they are not among the first fields but behind a separate option for business details that you open. Both then appear on the invoice. With a valid VAT identification number Paddle charges no VAT, because the liability shifts to you as the recipient; you then pay the net amount and therefore less than the stated final price. Without a number the final price is the same in every country, only the tax share within it changes. If the number was missed at checkout, you can add it yourself: sign in to the Paddle customer portal with the address you paid with, pick the payment under “Payment” and open “Update Invoice” there. The form holds your name, company name, tax number and the full billing address. Paddle allows this ONLY ONCE per purchase, so enter everything at once; the country can no longer be changed. For a refund of tax already paid, Paddle's buyer terms state a deadline of 60 days from the purchase. If you get stuck, write to us. Get in touch →

Any time, with no notice period, via the cancellation button on this website or directly at Paddle; you will also find the link in every payment confirmation. The subscription runs for one year and cancellation takes effect at the end of that paid year: until then the export stays unlocked, after that nothing further is charged.

For every calculator bought outright, at least 36 months of operation from the date of purchase are guaranteed, including the updates required to keep it contractually sound. We announce a discontinuation at least twelve months in advance in text form. From that announcement onwards no subscriptions are entered into or renewed, so every running subscription period is still performed in full. If the guaranteed operating period of a one-off purchase is still running at the shutdown date, we refund the share of the purchase price attributable to the remaining time. The reports and export files you already created are yours anyway and work independently of the website. See the terms of use →

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.

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.

Not for calculating. For the 17 calculators with a free report you do not need one for the PDF either. After a one-off purchase the export runs on the token from your purchase confirmation, again without an account. You need an account to save calculations, for the subscription, and when you want to use a one-off purchase on another device: as soon as you sign in with the address your purchase confirmation was sent to, the export is unlocked there without a token and the purchase is listed in your account. A one-off purchase does not create an account; it is created only when you sign in. For a subscription we create it automatically.

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.

Calculations run in your browser, on your device. Your inputs are only transmitted when you save a project or generate a document. Privacy policy →

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. Purchased unlocks expire with the deletion and cannot be restored - including a purchase that was made entirely without an account, where you only signed in later. Every unlock tied to the address of this account is deleted; the tokens from your purchase confirmation are worthless in every browser afterwards. So if you want to keep a one-off purchase, do not delete the account. A running subscription is not cancelled by this; cancel it with our payment partner Paddle.