Measure Anything in Photoshop
If you choose Analysis>Set Measurement Scale>Custom, you will get a dialog where you can set a series of presets. Although you are in the dialog, you can still move outside of it and click-and-drag out a measurement.
If you choose Analysis>Set Measurement Scale>Custom, you will get a dialog where you can set a series of presets. Although you are in the dialog, you can still move outside of it and click-and-drag out a measurement.