How it works
A 45 BPM metronome is Largo in Wikipedia's list of tempo markings (40 to 66) and on all three metronome dials pictured in German Wikipedia's Tempo article. Both sources call their figures approximate.
Read the full guide
Start
Tap the pad, or press Space. Clicks at 45 are far apart and all the same, with two equal dots taking turns: no bar is marked. Tap again to stop.
Change the tempo
Tap the number under the pad and type a tempo, or press minus and plus. One press either way lands on 44 or 46: both are notches in the arrangement Wikipedia's Metronome article calls the most common for a wind-up metronome, and 45 is not. Double time, 90, has a page of its own.
Questions and answers
Is 45 BPM largo or adagio?
Both, in Wikipedia's list of tempo markings, and Larghetto and Lento besides. Adagio and Larghetto open at 44, so 45 is their second number; Largo and Lento opened at 40. Adagietto starts at 46, one beat higher: 45 is the last whole tempo before it.
How wide is largo on a metronome dial?
It depends on the dial. In German Wikipedia's Tempo article a Japanese one of this century prints Largo over just 44 to 48, a 20th-century German one over 40 to 60 and a 19th-century French one over 42 to 70. 45 lies inside all three.
Which note lasts exactly one second at 45 BPM?
The dotted eighth: three quarters of the beat comes to 1,000 ms, by our sum. The eighth note is 666.7 ms, the sixteenth 333.3 ms and each note of an eighth-note triplet 444.4 ms.
How do I set 6/8 at 45 BPM?
Open the 6/8 metronome and type 45: it counts dotted quarters, three clicks to each, so 135 eighth notes a minute, by our sum. If your 45 counts eighth notes, type 15 there instead. This page marks no bar.
Why can't I hear the metronome?
Wait for a second click before deciding: at 45 they come well over a second apart. Then look at the ring switch, the volume and any Bluetooth device. The two dots change over on every beat, heard or not.