I built mg to mL as a single developer who wanted a useful tool to reuse whenever a mass-to-volume conversion came up. I wanted the concentration, units, and working to be visible together, instead of having to reconstruct the calculation each time.
My priorities are accuracy and ease of use. The calculator asks for the missing concentration or density, explains its arithmetic, and stays free to use. It is a tool for converting values you supply, not for choosing them for you.
I welcome corrections and practical suggestions at contact@mgtoml.app.