Example 1
100 cents gives 1.00 semitone. The frequency ratio is 1.05946.
Cents to Semitones Calculator
Enter cents from a tuner. The calculator divides by 100: semitones = cents ÷ 100. At 100 cents the result is 1.00 semitone, and the frequency ratio 2^(cents/1200) is about 1.05946. Minus 50 gives minus 0.50. The whole tone, octave fraction, and ratio come from the same field. Hertz f1 and f2 stay out.
Result
Enter cents. The result appears here.
Interval from Hz: semitones from a frequency pair. A Hz shift: transposition. A ratio of two hertz values: quotient f2/f1.
How it works
cents100
semitones1.00
In equal temperament an octave has 1200 cents and 12 semitones, so 100 cents is one semitone. The calculator divides the entered number by 100. One hundred cents is 1.00. Fifty is 0.50. Fourteen, a common tuning offset, is 0.14. Seven hundred is 7.00, a tempered fifth. Two hundred is 2.00, a whole tone. Twelve hundred is 12.00, an octave.
The sign stays. Minus 50 cents is minus 0.50 semitone: the measured pitch is below the target. Entered 0 is exactly 0.00, unison with the tuner target. Empty cents do not insert a zero. Only a number in the field goes through the quotient.
There is no logarithm of two frequencies here. The calculator does not ask for f1 and f2. If a tuner already gave cents, the calculator only scales them to semitones. The interval page first finds k from a hertz pair, then may show cents. Transposition takes k and a base frequency and multiplies that frequency by 2 to the power of (k/12). This converter does not multiply hertz.
The second result repeats cents to one decimal place, next to the semitones. Same number, different writing. The metric or US switch does not change a hundredth of a semitone. A cent stays a hundredth of a semitone, not a hundredth of a dollar.
A comma and a period mean the same, so 14.5 and 14,5 share the quotient 0.145. The main result keeps two decimal places and shows 0.15. Enter 100, click Calculate, and match 1.00. Then 50 and 0.50. For an octave enter 1200 or -1200, depending on direction.
When a new frequency is needed from those semitones, take k from the result and enter it in transposition with a base. Here the work stays a divide by 100, plus the ratio 2 to the power of (cents / 1200).
From the same number the calculator also finds a whole tone as cents / 200 and an octave as cents / 1200. At 100 cents the whole tone is 0.50, the octave fraction is 0.0833, and the frequency ratio is 1.05946. Fourteen cents give a ratio of 1.00812. The tempered fifth at 700 cents has a ratio of 1.49831, and 1200 cents has a ratio of 2.00000.
How to use
- Enter cents from a tuner. Minus means the pitch is low relative to the target.
- Click Calculate. 100 gives 1.00 semitone. 50 gives 0.50. Minus 50 gives -0.50.
- Entered 0 is unison, 0.00. An empty field does not insert a tuner zero.
- For an octave enter 1200 or -1200, depending on direction.
- The whole tone, the octave fraction, and the frequency ratio appear from the same field. A new frequency in hertz is computed by transposition.
Formula
semitones = cents / 100
whole tones = cents / 200
octaves = cents / 1200
ratio = 2(cents / 1200)
Alexander John Ellis defined the cent in 1885 as one hundredth of a semitone in equal temperament. An octave then has 1200 cents and a frequency ratio of 2. The input sign is kept. The calculator does not multiply hertz.
Tuner cents scaled to semitones
The calculator divides cents by 100. 100 cents is 1.00 semitone, 50 is 0.50, minus 50 is minus 0.50. Hertz f1 and f2 stay out.
- cents
- Hundredths of a semitone from a tuner, not hundredths of a dollar. 100 / 100 = 1.00. A 14 cent offset is 0.14. 1200 is an octave, 12.00.
- semitones
- cents / 100 in equal temperament. 100 cents is 1.00, a minor second. 700 cents is 7.00, a tempered fifth. The minus stays: -50 is -0.50.
- whole tone
- Cents divided by 200. At 200 cents the result is 1.00. At 100 cents it is 0.50. At 14 cents it is 0.07.
- ratio
- 2 to the power of (cents / 1200). At 100 cents it is 1.05946. At 1200 cents it is 2.00000. This is not a new frequency in hertz.
Real-life examples
Example 2
50 cents gives 0.50 semitone. The whole tone from this number is 0.25.
Example 3
1200 cents gives 12.00 semitones, one octave. The ratio is 2.00000.
Example 4
Minus 50 cents gives minus 0.50 semitone. The ratio is 0.97153.
Example 5
14 cents gives 0.14 semitone from the tuner. The ratio is 1.00812.
Example 6
700 cents gives 7.00 semitones, a tempered fifth. The ratio is 1.49831.
Example 7
0 cents gives 0.00, no offset. The ratio is 1.00000.
Example 8
200 cents gives 2.00 semitones, a whole tone. The ratio is 1.12246.
Ways to use this calculator
- You convert a tuner reading in cents to a fraction of a semitone before you move an oscillator in a DAW.
- You check whether a 14 cent offset is 0.14 semitone and a ratio of 1.00812.
- You fold 1200 cents into 12 semitones before you enter k in transposition.
- You read the frequency ratio from cents alone, without a hertz pair.
Frequently asked questions
How many semitones are 100, 50, and 1200 cents?
1.00, 0.50, and 12.00. 200 cents is 2.00, a whole tone. 700 is 7.00, a tempered fifth. At 100 cents the frequency ratio is 1.05946. At 1200 cents it is 2.00000.
Can I enter minus 50 cents?
Yes. The minus sign stays in the result. Minus 50 is minus 0.50, and the measured pitch is below the target. The frequency ratio is then 0.97153.
Do empty cents count as a tuner zero?
No. A result appears after you enter a number. Entered 0 is exactly 0.00.
How many cents are in an octave, and in a whole tone?
An octave is 1200 cents, 12 semitones, and a ratio of 2.00000. A whole tone is 200 cents, two semitones. A semitone always has 100 cents.
How is this different from an interval of two hertz values?
There is no f1 and f2 here. The calculator divides ready cents by 100. The interval page first finds k from a logarithm.
Is 14 cents a lot?
That is 0.14 semitone and a ratio of 1.00812. A tuner shows the offset. On a fixed synthesizer pitch it can already be audible.
Why does the second result repeat cents?
The second result shows cents to one decimal place, next to the semitones. One hundred cents appears as 100.0. Same number, different writing.
Does metric mode change a hundredth of a semitone?
No. A cent stays a hundredth of a semitone. The metric or US switch does not change this quotient.
How do I turn these semitones into a new frequency?
Take k from the result and enter it in transposition together with a base Hz. This converter does not multiply hertz.
Does a comma in 14.5 work?
Yes. 14.5 and 14,5 share the quotient 0.145. The main result keeps two decimal places, so it shows 0.15. Enter the tuner number alone, with no space in the middle.
Where does the frequency ratio come from?
The calculator computes 2 to the power of (cents / 1200). That is the definition of the cent in equal temperament, the same number as semitones divided by 12. At 100 cents the ratio is 1.05946. At 700 cents, for a tempered fifth, it is 1.49831.
How do I convert cents to semitones?
Divide cents by 100. At 100 cents: 100 ÷ 100 = 1.00 semitone. At 50: 0.50. At 1200: 12.00 (one octave).
How many semitones and what ratio is 100 cents?
1.00 semitone. The frequency ratio is 2^(100/1200) ≈ 1.05946 — the equal-tempered semitone by definition.
How do I get a frequency ratio from cents?
Raise 2 to the power of (cents ÷ 1200). At 700 cents (tempered fifth): 2^(700/1200) ≈ 1.49831. At 1200: exactly 2.
How is this different from an interval of two frequencies in hertz?
Here you enter ready cents from a tuner and divide by 100. An Hz interval calculator first finds cents with 1200 × log₂(f2/f1).
How many cents are in a semitone, a whole tone, and an octave?
A semitone is 100 cents, a whole tone 200, an octave 1200. That is Ellis’s scale in 12-TET equal temperament.
What does minus 50 cents on a tuner mean?
The pitch is 0.50 semitone below the target. The ratio is 2^(−50/1200) ≈ 0.97153. The minus sign stays in the result.
Knowledge sources
The cent in this calculator is the unit Alexander John Ellis defined in 1885: one hundredth of a semitone in equal temperament.
Page updated November 3, 2026.