Semitone Calculator
Category: MusicCalculate musical intervals, frequency ratios, and note relationships with this semitone calculator. Find the distance between notes, transpose melodies, or convert between frequencies and notes.
Calculate Note Relationships
Music Theory Basics
What are Semitones?
A semitone (or half step) is the smallest musical interval commonly used in Western tonal music. It's the distance between two adjacent notes on a piano keyboard. In equal temperament, a semitone represents a frequency ratio of approximately 1.0595:1 (the 12th root of 2).
Common Musical Intervals
| Semitones | Interval Name | Ratio (Just Intonation) | Example |
|---|---|---|---|
| 0 | Perfect Unison | 1:1 | C to C |
| 1 | Minor Second | 16:15 | C to D♭ |
| 2 | Major Second | 9:8 | C to D |
| 3 | Minor Third | 6:5 | C to E♭ |
| 4 | Major Third | 5:4 | C to E |
| 5 | Perfect Fourth | 4:3 | C to F |
| 7 | Perfect Fifth | 3:2 | C to G |
| 12 | Perfect Octave | 2:1 | C to C' |
Note Frequencies
In standard tuning, A4 (the A above middle C) is set to 440 Hz. Each semitone up or down changes the frequency by a factor of the 12th root of 2 (approximately 1.0595). The formula for calculating the frequency (f) of a note is:
Where n is the MIDI note number (A4 = 69) and A4 is the reference frequency (typically 440 Hz).
What Is the Semitone Calculator?
The Semitone Calculator is a musical tool that helps you understand and work with the relationships between musical notes, frequencies, and intervals. Whether you're a student, performer, composer, or hobbyist, this tool can simplify common music theory tasks and offer helpful insights into pitch relationships.
You can use it to:
- Measure the number of semitones between two notes
- Identify the name and quality of musical intervals
- Convert a frequency to the closest musical note
- Transpose entire sequences of notes up or down
Formula for Frequency Calculation
Frequency of a note:
f = A4 × 2(n - 69) / 12
Where:
- f is the frequency in Hz
- A4 is the reference pitch (usually 440 Hz)
- n is the MIDI note number (A4 = 69)
How to Use the Semitone Calculator
The calculator is divided into three main functions, each accessed using a tab:
1. Note to Note
Find the interval and frequency ratio between any two musical notes.
- Select two notes using the dropdown menus
- Check optional settings like "Play Notes" or "Show Cents"
- Click "Calculate" to see the results
2. Frequency to Note
Convert a frequency in Hertz (Hz) to its nearest musical note.
- Enter the frequency and your reference pitch (default is 440 Hz)
- Enable sound or nearest notes view if needed
- Click "Calculate" to find the closest note and tuning information
3. Transpose
Shift a sequence of notes up or down by a chosen number of semitones.
- Enter the notes (e.g., C4 E4 G4)
- Set how many semitones to transpose and choose the direction
- Click "Calculate" to view original and transposed results
Why This Tool Is Useful
Music involves more than just notes on a page. Understanding how those notes relate helps in everything from arranging harmonies to tuning instruments. This calculator offers practical support by:
- Helping you quickly analyze intervals and pitch distances
- Assisting with ear training and tuning accuracy
- Supporting music transcription, arrangement, and chord identification
- Offering a visual representation of changes through piano key diagrams
Whether you're learning music theory, exploring harmonies, or simply curious about pitch relationships, this calculator offers instant feedback to guide your work and creativity.
Frequently Asked Questions (FAQ)
What is a semitone?
A semitone is the smallest standard interval in Western music. It’s the distance from one key to the next on a piano keyboard, such as from C to C♯.
What is a musical interval?
An interval is the distance between two notes, measured in semitones. Common intervals include major thirds (4 semitones) and perfect fifths (7 semitones).
How accurate is the frequency-to-note converter?
The calculator uses precise logarithmic math and can display how many cents (1/100th of a semitone) a frequency is off from the nearest note.
Can I use this tool to tune an instrument?
Yes. Use the frequency-to-note tab to check how close a pitch is to the correct tuning and follow the visual tuner suggestions.
What is transposition in music?
Transposition means shifting a group of notes up or down by a certain number of semitones. This is helpful for changing the key of a melody or adapting it for different instruments.
Summary
The Semitone Calculator is a straightforward and flexible tool for analyzing, converting, and exploring musical notes and frequencies. With its user-friendly interface, helpful visual feedback, and optional sound playback, it can support your musical goals—whether you're learning, practicing, or composing.