The Beat Snap Divisor is used to limit where notes can be placed so that they always fall on the beat. Moving the slider to the right increases the granularity of the notes, that is, more notes can be placed in the same measure.
Each of the settings put different colours of ticks on the Timelines. The ticks are as follows (for Standard, osu!taiko, and osu!catch):
Divisor 1/1
Divisor 1/1
- Full Beats
- White ticks only
- Best used for Easy difficulty.
Divisor 1/2
Divisor 1/2
- Half Beats
- Adds red ticks
Divisor 1/3
Divisor 1/3
- Triplets*
- Has two purple ticks between each white tick
- Compound timing
Divisor 1/4
Divisor 1/4
- Quarter Beats
- Adds blue ticks, in addition to the red ticks
- Useful for general mapping.
Divisor 1/6
Divisor 1/6
- Double Triplets*
- Has two purple ticks between each red tick
- Compound timing
Divisor 1/8
Divisor 1/8
- Eighth Beats
- Adds yellow ticks, in addition to the red and blue
The 1/3 and 1/6 are special because it means your BPM is divisible by three, but this is rare.
Holding down the Alt button over the slider changes it to the distance spacing slider
osu!mania
Double white line: Measure
White line: Common Time
Green line: You.
Divisor 1/1
Divisor 1/1
- Full Beats
- White ticks only
- Best used for Easy difficulty.
Divisor 1/2
Divisor 1/2
- Half Beats
- Adds red ticks
Divisor 1/3
Divisor 1/3
- Triplets
- Has two purple ticks between each white tick
- Compound Timing
Divisor 1/4
Divisor 1/4
- Quarter Beats
- Adds blue ticks, in addition to the red ticks
- Useful for general mapping
Divisor 1/6
Divisor 1/6
- Double Triplets
- Has two purple ticks between each red tick
- Compound timing
Divisor 1/8
Divisor 1/8
- Eighth Beats
- Adds yellow ticks, in addition to the red and blue
Divisor 1/12
Divisor 1/12
- Twelveth Beats
Divisor 1/16
Divisor 1/16
- Sixteenth Beats