MIDI stands for Musical Instrument Digital Interface. It is a standard specifying a way in which software and electronic devices can transmit and receive music. The Play Note () for () Beats block plays a note with the pitch represented by its input according to the MIDI Note System, and it can be used repetitively to play any sequence of MIDI notes. The volume, tempo, or instrument used can be changed seperately.

MIDI Note System

Play Note () for () Beats uses the MIDI note system. Each note is represented by a number. A note can be selected by either typing in a number or pressing a key on the virtual keyboard. 60 represents middle C. Adding or subtracting 1 is equivalent to moving one semitone higher or lower, respectively. Adding or subtracting 12 changes the note by one octave.


MIDI may be tricky to use since it does not have the regular notation for notes and durations. These diagrams might help:


The note names are written on the keys. Notes written in the two most common clefs (treble clef and bass clef) are connected to the piano. All notes can be written in an infinite number of ways. The most common enharmonic notes are included. A line going from a long red box means the notes go to the same key on the piano. Even though the drop-down keyboard on each block shows only one octave of notes, a number can be put in manually to get any note. To change octaves, simply add or subtract 12, or click on the arrows at the top of the keyboard.

There are 131 notes on Scratch's keyboard, numbered from 0 (C-1, about 8.18 Hz) to 130 (B♭9, about 14917.24 Hz). Each note is 1 number larger than the previous, and the ratio of frequency is always 122 (approximately 1.06), with A4 being 440 Hz.

Note Note number Frequency
C3 48 131 Hz
C♯3/D♭3 49 139 Hz
D3 50 147 Hz
D♯3/E♭3 51 156 Hz
E3 52 165 Hz
F3 53 175 Hz
F♯3/G♭3 54 185 Hz
G3 55 196 Hz
G♯3/A♭3 56 208 Hz
A3 57 220 Hz
A♯3/B♭3 58 233 Hz
B3 59 247 Hz
C4 (middle C) 60 262 Hz
C♯4/D♭4 61 277 Hz
D4 62 294 Hz
D♯4/E♭4 63 311 Hz
E4 64 330 Hz
F4 65 349 Hz
F♯4/G♭4 66 370 Hz
G4 67 392 Hz
G♯4/A♭4 68 415 Hz
A4 69 440 Hz
A♯4/B♭4 70 466 Hz
B4 71 494 Hz
C5 72 523 Hz


This table shows the beat number values for the most common rhythms in the most common time signatures, interpreted in the most basic way.

WholeNote.png DottedHalf.png HalfNote.png DottedQuarterNote.png QuarterNote.png QuarterTriplets.png Dotted8th.png 8thNote.png 8thTriplets.png Dotted16th.png 16thNote.png
TimeSig4.png 4 3 2 1.5 1 0.67 0.75 0.5 0.33 0.375 0.25
TimeSig8.png 8 6 4 3 2 1.33 1.5 1 0.67 0.75 0.5
TimeSig2.png 2 1.5 1 0.75 0.5 0.33 0.375 0.25 0.167 0.1875 0.125

MIDI Instruments

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A list of the instruments available prior to Scratch 2.0 can be found here.


In versions prior to Scratch 2.0, Scratch used MIDI for the music blocks. The Play Drum () for () Beats block offered the 47 drums specified by General MIDI, and Set Instrument to () offered the 128 instruments specified by General MIDI. A MIDI synthesizer or sampler on one's computer would play each note or drum sound produced by a music block.

Scratch 1.3 was able to generate MIDI notes from the microphone, using the Note block.

When Scratch 2.0 was released, Scratch stopped using MIDI to create notes and drums.[1] Instead, Scratch now uses sampled instruments to play the various notes and drum sounds;[2][3] however, it still uses MIDI's note numbering system.

See Also