A verse can feel crowded and you cannot hear why. You play it back, it sounds rushed in one place and draggy in another, and the only thing you can say about it is that something is off. Density is the part you can actually count: how many syllables each bar carries, and how fast that is once you know the tempo.
Paste a verse one bar per line, tell it the BPM, and every bar comes back with a syllable count, a syllables-per-second rate, and a bar showing how it compares to the rest of the verse. The bars that are doing something different from their neighbours get marked, which is usually where the problem — or the deliberate accent — is.
It runs entirely in your browser. No upload, no account, no audio to analyse: you bring the words and the tempo, and the arithmetic happens on your own machine. The result is a plain .txt or .csv you can keep.
Paste a verse to get started.
Nothing measured yet.
The bar sits where the verse sits: amber bars carry at least a third more syllables than the middle bar, teal ones at least a third fewer. Both are worth a look — a crowded bar is usually the one you trip over, and a thin one is usually where the groove breaks.
Your text never leaves the browser. There is no upload anywhere in the code on this page, and no server receives what you paste.
There is no save button, because there is no account. That also means no autosave — export before you close the tab or you will be doing it again.
Reading a flow map
Six things that make the numbers worth having.
- Set the real tempo first. Density is meaningless without it — fourteen syllables is relaxed at 70 BPM and breathless at 140, and the tool has no way to guess which you meant.
- Read the middle bar as the verse’s own normal. The readout tells you what it is, because “too many syllables” only means something relative to the flow you have already established.
- Go to the amber bars first. Those are the ones carrying at least a third more than the middle bar. If a line feels like you are sprinting through it, it will be amber, and the fix is usually to cut a phrase rather than to speed up.
- Look at the teal bars before you cut anything. A bar that is much thinner than the rest is often a breath you put in on purpose, or a bar where the beat drops out. Deleting those is how a verse ends up relentless and tiring.
- Use the rate, not the count, when you are comparing songs. Syllables per second is the number that survives a change of tempo, so it is the one to quote when you are trying to match the feel of a reference track.
- Export the table when you are rewriting. Having the count beside every line makes it obvious which bar to attack, and whether cutting one line leaves the bar next to it suddenly standing out.
Why count instead of listening
Because your ear is doing five other things at once.
Listening to your own verse is not a measurement. You are hearing the beat, the rhyme, the take, whether the ad-lib landed, and whether the melody works — and noticing “that bar is busy” somewhere underneath all of that. A count isolates one variable and puts a number on it, which turns a feeling into something you can act on deliberately.
Density is also the thing that separates flows people recognise. The difference between a laid-back verse and a technical one is rarely the rhyme scheme or the subject; it is how much is being fitted into the same stretch of time, and where the writer chooses to leave space. Seeing your own pattern written down — dense, dense, thin, dense — is often the first time you notice you have one.
The honest limits: this counts written syllables, not performed ones. Rap regularly elides, slurs and drops vowels, so the sung syllable count is often lower than the written one, and a bar that looks crowded on paper can be effortless in the mouth. It also has no idea where you actually place the words inside the bar — swing, off-beat entries and rests are all invisible to it. Treat the numbers as a map of what you wrote, and confirm them by performing the verse, which you were going to do anyway.
Common questions
Is my verse uploaded anywhere?
No. The whole tool runs in your browser. Your text stays in a textarea, the file is built on your own machine when you press Download, and nothing is sent to a server at any point. The site still runs analytics and cookies like any other site — those are described in the privacy policy — but your words are not part of them.
How is syllables per second worked out?
Syllables in the bar divided by the length of the bar in seconds, and the bar length comes from your tempo: sixty divided by the BPM, times the beats in a bar, times how many bars a line stands for. At 90 BPM with four beats a bar, one bar is 2.67 seconds, so a bar with sixteen syllables runs at six a second.
Why does the syllable count look wrong?
Because it counts what is written, not what is sung. English spelling is a poor guide to English sound, and rap elides aggressively — every is often one syllable in the mouth and two on the page. The counts are consistent bar to bar, which is what makes the comparison useful, but the absolute number is a written-syllable figure, not a performed one.
What do the amber and teal bars mean?
Amber carries at least a third more syllables than the middle bar of the verse, teal at least a third fewer, with a floor of three syllables so short verses do not turn into a wall of colour. Neither is a mistake: a crowded bar can be the hook of the verse and a thin one can be the breath before it. The point is that they should be choices.
Does it work for singing rather than rapping?
Yes, with the bar length set honestly. Sung lines often run two bars rather than one, so set 2 bars a line and the rates come out right. What it cannot judge is whether a line is comfortable to sing — vowel shape and range matter more than count there.
Can I check my rhyme scheme at the same time?
Different tool, same browser: the Rhyme Scheme Mapper labels the end sounds line by line, and the Prosody Scanner marks stress within a line. Between them you get density, rhyme and meter for the same verse.
Back to writing
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Or go back to the full list of tools, the generators I use most, or the most recent batch.