Tempo
See also: Timing
The song's tempo, equal to 187, can be seen on the top corner of the beatmap information page
Tempo refers to the speed of a song. It is typically measured in beats per minute (BPM), meaning the number of whole musical beats in a minute of a song. For example, a tempo of 60 beats per minute signifies one beat per second, while a tempo of 120 beats per minute is twice as rapid, signifying two beats every second. The tempo directly affects a lot of gameplay aspects, such as slider velocity, or kiai time strobing. Beatmap information pages display tempo beside a metronome symbol, a device used by musicians that assists in playing to a regular pulse.
Gameplay
Many osu! elements base their timings around the current song's tempo:
- Gameplay speed, due to songs with higher tempo having shorter beats
- Frequency of kiai time strobbing
- Countdown speed
Beatmapping
Timing points use a BPM and offset to allow snapping hit objects to the timeline when creating beatmaps. Timeline snapping ensures gameplay aligns with the beat.
The timing tab of the beatmap editor contains a BPM estimation tool, which calculates beatmap timing by tapping along with the song. The results obtained, however, usually require additional adjustment to be accurate.
Most modern songs use a single BPM, which requires a single timing point. More complex songs may require multiple timing points and metronome resets to be timed correctly. Timing points are shown as red lines in the timeline at the bottom of the editor.