How do I find the BPM of a song?

Open it in Risocast (click it anywhere, or search with Ctrl+F) and choose the Sound tab. The tempo is at the top.

How accurate is the BPM?

Close for most songs. The common error is counting double or half time, which Risocast flags by showing both figures.

Why is there no key for some songs?

Songs measured from a 30-second preview don't get a key; the rest of the measures still do.

BPM, key and sound

BPM, key and how a song sounds

Open any song in Risocast and its Sound tab shows the tempo in BPM, the key, the loudness, and seven measures of how it sounds: energy, danceability, mood, acoustic, instrumental, spoken and live. A line of words sums it up, such as “Mid-tempo, energetic and mostly instrumental, in D major.”

What each measure means

Measure	What it tells you
Tempo	Beats per minute, as the song is felt (see below).
Key	The song's key and whether it's major or minor, such as A major.
Loudness	Average loudness in decibels; the closer to 0, the louder.
Energy	How intense and busy it feels, from calm to intense.
Danceable	How steady and regular the beat is.
Mood	How happy (high) or sad (low) it sounds.
Acoustic	How likely it is to be played on acoustic instruments.
Instrumental	How likely it is to have no vocals.
Spoken	How much of it is spoken words rather than singing.
Live	How likely it is to be a live recording.

Tempo as it's felt

Beat trackers often count every half-beat, so a song felt at 84 BPM reads as 168. When a very fast reading comes with a song that isn't danceable, Risocast shows the felt tempo, 84 BPM, and keeps the counted figure beside it (“or 168”); a very slow reading on a very danceable song is doubled the same way. A genuinely fast song, like drum and bass at 174, can read like this too, which is why both numbers stay.

Where the numbers come from

Most measurements come from ReccoBeats, which publishes audio features for millions of recordings; a few thousand songs already had them in Risocast's catalogue. For songs it doesn't know yet (small and new releases), Risocast has ReccoBeats measure the song's 30-second preview instead, and says so (“From a 30-second clip”). A clip gives everything but the key. Each song is measured once and kept.

On the song's public page too

Song pages on risocast.com show the tempo and key where they're known, so you can look a song up without the app. Browse by genre.

Questions

How do I find the BPM of a song?: Open it in Risocast (click it anywhere, or search with Ctrl+F) and choose the Sound tab. The tempo is at the top.
How accurate is the BPM?: Close for most songs. The common error is counting double or half time, which Risocast flags by showing both figures.
Why is there no key for some songs?: Songs measured from a 30-second preview don't get a key; the rest of the measures still do.
Is it free?: Yes.