Everything is free right now.

All 57 calculators, every work trail, every hazard flag, and the unit converter are free and always will be. Paid plans are not switched on yet, so nothing on this site can charge you today.

When they arrive, the split will be simple. Calculating, the full working, and export of anything you make stay free forever. What is paid is keeping that work: permanent searchable history, printable formula sheets, Curie remembering your reagents, and sharing a library with your lab.