There are three different ways the note of a bell can be shown - By Note, Strike Note or the frequency of the Nominal.

1) By NOTE

The simplest way is by the Note, for example 'Ab'. This notation is in common use, for example Doves' Guide and in many church ringing chambers. Unfortunately this information is usually incomplete as one needs to know which pitch and musical scale. Even if the scale and pitch are known, the bell could be up to half a semitone flat or sharp of the Note. This deficiency is overcome nowadays by specifying the difference between the International and actual pitch in cents : e.g. Ab+12 cents.
Unless specified otherwise, Notes given in bell-founders & hangers reports use the Standard International pitch.

2) By Strike Note

For a Simpson-tuned bell the strike note will be half the frequency of the Nominal partial, and the same frequency as the Prime partial.

The frequencies are usually given in the SI units of Hertz (Hz) but the superseded terminology of Cycles per Second (c.p.s) is still used by some members of the trade.

A bell of Nominal frequency 798Hz could be described as having a Strike Note of 399Hz (c.p.s).

3) By Nominal Frequency

Frequencies are independent of musical scale and allow a quicker comparison between bells.

It is common for the frequencies of the Hum, Prime, Tierce and Quint partials to be given as well as the Nominal partial. This information may be accompanied by the difference (or error) between the bell's partial and the theoretical value of a Simpson tuned bell.

Error (in cents) =  1200    log          f_partial             
                             log(2)           f_nominal * Ratio_partial

where:
f_partial is the frequency of the partial.

f_nominal is the frequency of the Nominal.

Ratio_partial is the Simpson tuned ratio for the partial. The ratios for Simpson tuning are: Hum  : 0.25, Prime : 0.50, Tierce : 0.60 and Quint : 0.75, Nominal : 1. More information about Simpson tuning.

For example a bell of Nominal frequency 800Hz and Hum frequency 215Hz would be 125 cents sharp of a Simpson tuned bell which should have a hum note of 200Hz.