The calculator on the Wheelpro website accepts numeric input and calculates the spoke lengths. It's what I use, and my preference is to always measure my own components, enter the dimensions and get the spoke lengths.
I had a request to allow the calculator to accept url parameters (this is explained in the calculator Text Data help page). Now that it was accepting external parameters, I decided to extend the funcionality so that the parameters could also be sent from an external web page.
The application program interface (api) allows you to access the calculation engine of the Wheelpro spoke length calculator. You can create a front end on your website, and fire off data, and it will return the calculation for you to display on your site. A typical use would be to add a database of hubs and rims, because there are people out there who have a genuine requirement for doing this, and are capable of creating a database with accurate dimensional information.
It costs nothing. All I ask is that you include a credit somewhere, with a link to https://www.wheelpro.co.uk. There's no Wheelpro branding on the calculator output.
None whatsoever, it's provided free of charge, as is.
Feedback and requests
Any features you'd like? Seen any bugs?
Let me know.