Here are a number of microstrip calculators that have been used, both at microwave and RF. The microstrip line calculator is the self same one used for a well known interdigital capacitor design.
A simple calculator for the characteristic parameters of a Quasi-Static TEM mode microstrip line with up to two ground planes and three dielectrics. Add a real substrate from the catalog.
A development to cover TEM mode coupled lines. Try the compensated and interdigital formats!
A development of the microstrip line to match two impedances. Different step profiles.