I think a welcomed feature would be a Impedance Calculator for 4 Layer Boards like JLC PCB is offering it.
Impedance calculators shipped with EDAs are often very overwhelming for new users. A simplified tool on the website would take away the complexity. The results are sufficient enough to be usuable with typical Interfaces like USB.
Welcome to the community!
Thank you for your suggestion - we had considered providing an impedance calculator, but decided against it for the time being.
The calculation of impedances is a complex topic with potentially numerous influencing variables (vias, angles, meanders…) which might effect the final result. A simplified calculator would not do justice to this complexity, even though it would probably provide sufficient accuracy in many cases. Beside this, it is difficult to specify manufacturing accuracies for the variance of calculated configurations.