Frequency of A4 (Concert A)
A4 (concert A) has a frequency of 440 Hz — the standard tuning reference.
How to use this tool
- Enter note and octave in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your frequency and the full breakdown beneath it.
A4 is the concert pitch reference at 440 Hz, used for tuning instruments worldwide.
Frequently asked questions
- What frequency is middle C?
- Middle C (C4) is approximately 261.63 Hz in standard A4=440 tuning.
- What is A4 in Hz?
- A4 is 440 Hz by international standard (ISO 16:1975).