A small plug-in with some useful conversion features.
The following conversion functions are included in this version:

dB to linear
Linear to dB
dB to percent
Percent to dB
BPM to beat length
Beat length to BPM
Degrees to radians
Radians to degrees

In addition it can add a series of numbers, or multiply a series of numbers.
It is also able to run simple Nyquist commands that produce a printable result.

It has been written in a modular way so it is pretty easy if anyone wants to add more functions or customise it in any way.

Installing the plug-in.
This is done in the usual way - just put the .ny file into your Audacity plug-ins folder and restart Audacity.
This plug-in will be listed in the Generate menu (the only type that allows a Nyquist plug-in to run without a track selection).
It will be listed as: “Quick Calculator”.

As usual, any feedback, problems or suggestions, please post as a reply here on the forum. qcalc.ny (2.63 KB)
Download Current Version

One more function added (thanks Robert J.H. for the suggestion).

dB to linear

dB to percent

BPM to beat length

Midi note number to Frequency (Hz)

Frequency (Hz) to cycle period (seconds)

Frequency (Hz) to cycle length (samples)

Tempo Change as %

Degrees to Radians

Addition

Multiplication

Division

Nyquist script

“Tempo Change as %” may be useful when using the “Change Speed” or “Sliding Time Scale / Pitch Shift” effects.
If you know the current tempo in bpm and the desired tempo in bpm, use “Tempo Change as %” and enter the original tempo and target tempo as two numbers (separated by a space).
For example, if you want to change the tempo from 160 bpm to 180 bpm, enter: 160 180 qcalc.ny (5.31 KB)

The Quick Calculator is more accurate.
For example, according to “Change Tempo”, from 45 to 33.3333 = -26.667 (tempo values are truncated to integers).
Quick Calculator gives the answer, from 45 to 33.3333 = -25.926 (correct to 3 decimal places).

Added “Length Change as %”.
This can be used with “Change Speed”, “Change Tempo” and ‘Sliding Time Scale / Pitch Shift’ effects.

Example:
To stretch 1 minute and 22.5 seconds to 1 minutes and 30 seconds, you can either work out the required ‘percent’ for “Change Speed”, “Change Tempo” or ‘Sliding Time Scale / Pitch Shift’ effects in minutes or in seconds (but both the initial duration and final duration must be in the same units.
1 minute and 22.5 seconds = 82.5 seconds
1 minutes and 30 seconds = 90 seconds
Select “Length Change as %” in the Quick Calculator and enter:

82.5 90

The calculator returns:

Duration change from
82.5 to 90 is -8.33333 %.

The value -8.33333 can then be entered into the “Change Speed”, “Change Tempo” or ‘Sliding Time Scale / Pitch Shift’ effects.

Note that the Change Tempo effect may not produce precisely the desired length due to limitations of that effect.
Note that for ‘Sliding Time Scale / Pitch Shift’ the value must be entered as the Initial and Final tempo change to produce the target length.

Also added the ‘Inverse’ function for “Divide (a/b)” and a couple of wording refinements. qcalc.ny (6.24 KB)

Here’s a workaround.
This version copies the output text into the Nyquist debug window. (Click the “Debug” button rather than the “OK” button).

A known limitation of this workaround version: Some of the formatting in the debug window may look a bit strange (for example, “new line” characters will sometimes be printed as “\n”) qcalc-win.ny (6.45 KB)