Should I use average ride power or FTP for the power entry? +
Use FTP when the question is threshold power-to-weight or FTP training zones. Average power from an entire ride usually includes descending, coasting, stops, and varied intensity, so it does not represent FTP. For another comparison, such as five-minute W/kg, enter the power from that duration and label the result accordingly.
Does a higher watts-per-kilogram result always mean I will ride faster? +
No. W/kg is especially informative when gravity is a major resistance, such as on sustained climbs. On flatter roads, absolute power, aerodynamic drag, rolling resistance, wind, drafting, and riding position can matter more. The calculator describes the relationship between power and mass; it does not predict speed or finishing time.