The Just tuning reference article from the English Wikipedia on 24-Apr-2004
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Just tuning

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Just intonation is any musical tuning in which the frequencies of notes are related by whole number ratios. This table shows one possible scheme of implementing just intonation frequencies.

Just tuning frequencies of all notes in each key based on A = 440 Hz when in the key of C. The just intonation scale ratios of 24:27:30:32:36:40:45 are used and each key note has the same frequency in the scales with +/- 1 sharp or flat.

Note that the 6th note in a key changes frequency by a ratio of 81/80 when it becomes the 2nd of the key with one more sharp or one less flat. All other notes retain the same frequency. In C all frequencies are an exact number of Hertz.

In just intonation incidentals tuning must be worked out on a case by case basis. Often the minor third and minor seventh take the ratios 28 and 42 when the tonic is taken as 24, so that in C the tuning for Eb and Bb would be 308 Hz and 462 Hz. These frequencies allow dominant seventh chords with frequency ratios of 4:5:6:7.

For frequencies in other octaves repeatedly double or halve the tabulated figures.

There is a difference between Gb and F# which amounts to a ratio of = 1.0136433 as discovered by Pythagoras.

Key \\ Note C Db D Eb E F Gb G Ab A Bb B
Gb (6b) 278.123 309.026 347.654 370.831 417.185 463.539 494.442
Db (5b) 260.741 278.123 312.889 347.654 370.831 417.185 463.539
Ab (4b) 260.741 278.123 312.889 347.654 391.111 417.185 469.333
Eb (3b) 260.741 293.333 312.889 352 391.111 417.185 469.333
Bb (2b) 264 293.333 312.889 352 391.111 440 469.333
F (1b) 264 293.333 330 352 396 440 469.333
C (0) 264 297 330 352 396 440 495
G (1#) 264 297 330 371.25 396 445.5 495
D (2#) 278.438 297 334.125 371.25 396 445.5 495
A (3#) 278.438 297 334.125 371.25 417.656 445.5 501.188
E (4#) 278.438 313.242 334.125 375.891 417.656 445.5 501.188
B (5#) 281.918 313.242 334.125 375.891 417.656 469.863 501.188
F# (6#) 281.918 313.242 352.397 375.891 422.877 469.863 501.188
Key / Note C C# D D# E F F# G G# A A# B
Equitempered 261.626 277.183 293.665 311.127 329.628 349.228 369.994 391.995 415.305 440.000 466.164 493.883