Free Note Frequency Calculator

Instant Note-to-Frequency & Pitch Conversion

This musical note frequency calculator (often called a pitch to frequency converter or music note Hz calculator) quickly determines the exact frequency of any note in the twelve‑tone equal temperament system. Whether you need a musical note Hz calculator for practice, arranging, or audio engineering, this tool covers the full range from C0 to B8 and gives you the corresponding pitch in hertz. An integrated equal temperament frequency chart lets you reference all note‑octave pairs at a glance.

Physics of Sound and Pitch

Sound travels as a wave through a medium such as air or water. Two fundamental properties define every sound wave: amplitude (which we perceive as volume) and frequency (which determines pitch). Frequency is the number of wave cycles that occur in one second, expressed in hertz (Hz). For instance, the note C4 vibrates at approximately 262 Hz, meaning the air oscillates 262 times every second.

The Twelve‑Tone Equal Temperament System

Since the 18th century, the most widely used tuning system has been the twelve‑tone equal temperament. In this system every half‑step (semitone) is spaced by a constant ratio: $2^{1/12}$. The reference pitch is A4, which is set to 440 Hz – an international standard since 1939. Using this reference, any note’s frequency can be calculated with the formula:

$$f(n) = 440 \times 2^{(n-69)/12}$$

where $n$ is the MIDI note number (69 corresponds to A4). Doubling the frequency raises the pitch by exactly one octave, which is why notes separated by octaves share the same letter name (e.g., A3 = 220 Hz, A4 = 440 Hz, A5 = 880 Hz). This naming convention is known as scientific pitch notation.

Using the Note Frequency Converter

Operating the converter is straightforward:

1. Select the note name – enharmonic equivalents (such as C♯ / D♭) produce the same frequency.
2. Choose the octave number – from 0 to 8, covering the full audible range.
3. Adjust the decimal precision – the default rounding is to two decimal places, but you can increase the value if desired.

The tool instantly returns the frequency in Hz and can also be used to convert a pitch back to the nearest note using the same equal temperament standard.

Reference Table: Note Frequencies (Rounded to Nearest Hz)

Note	Oct 0	Oct 1	Oct 2	Oct 3	Oct 4	Oct 5	Oct 6	Oct 7	Oct 8
C	16	33	65	131	262	523	1047	2093	4186
C♯	17	35	69	139	277	554	1109	2217	4435
D	18	37	73	147	294	587	1175	2349	4699
D♯	19	39	78	156	311	622	1245	2489	4978
E	21	41	82	165	330	659	1319	2637	5274
F	22	44	87	175	349	698	1397	2794	5588
F♯	23	46	93	185	370	740	1480	2960	5920
G	25	49	98	196	392	784	1568	3136	6272
G♯	26	52	104	208	415	831	1661	3322	6645
A	28	55	110	220	440	880	1760	3520	7040
A♯	29	58	117	233	466	932	1865	3729	7459
B	31	62	123	247	494	988	1976	3951	7902

These values are rounded to the nearest whole number. For precise calculations (e.g., audio synthesis), you can obtain the exact figures from the formula above.

Additional Features and Integration

The equal temperament frequency calculator also supports conversions between frequencies and semitones. If you need to determine the interval between two pitches or find the note that corresponds to a given frequency, the underlying algorithm uses the semitone ratio $2^{1/12}$ to deliver accurate results. All calculations are based on the A4 = 440 Hz standard but can be adapted to other reference pitches (e.g., A4 = 432 Hz) by adjusting the base value.