Least Squares
This tool will help you to hear and evaluate different tuning theories in light of actual measured pitches. Enter the pitches of a scale you have measured or invented, and one or more theoretical tunings you suspect it might embody. The discrepancy (comma) between theoretical and actual tones is reported in cents. This method uses a simple least-squares method; for a Bayesian approach, click the Bayesian link above. The playground link lets you explore subtle discrepancies between different tuning systems.
These can be loud! Start with your system volume down very low and gradually increase.
Treats your lowest pitch as 1:1; every theory is anchored there.
These are your data, what you actually heard and measured. Everything else is a theory about them. Order them low to high; a theory needn't have the same number of tones, since each measured pitch is matched to its nearest tone in the theory.
A ratio set: write each interval above the tonic as x:y (or x/y), separated by spaces or commas, e.g. 1:1 9:8 5:4 4:3 3:2 5:3 15:8 2:1. An n-EDO grid divides the octave into n equal steps (not ratios); you give only n, and the grid is matched to your scale automatically.