TapTempo.oneOne action is enough
TapTempo.one is a tap tempo page built around one prominent surface. Follow a recurring pulse and activate the surface with pointer, touch, Space, or Enter. After one interval the page can show a temporary rate. After at least four taps, it shows the median BPM from the newest available intervals, using no more than eight.
The interface deliberately avoids a statistics dashboard. There is no mean, range, MAD, CV, tape, comparator, trimmer, bar conversion, history table, or multi-tool workspace. The goal is orientation: one pulse, one answer.
Choose the event first
Tap every occurrence of the same event. Quarter notes are a common choice, but a dotted-quarter compound pulse, half-time backbeat, step, or cue pulse can also be valid when clearly labeled. Do not alternate levels inside one sequence.
If you tap eighth-note subdivisions while another person expects quarter-note BPM, your value will be about double. The page displays half-time and double-time candidates to prompt that question; it cannot decide the correct musical convention.
What happens behind the disc
Each accepted activation records performance.now() in the current page. The difference between neighboring timestamps becomes an interval. For interval d milliseconds, the temporary rate is 60000 / d.
Once four taps exist, three or more intervals are available. The page converts the newest intervals to BPM and takes their median, using at most eight gaps. With an even number of values, median is the average of the two middle rates. Older gaps fall out of the answer without becoming a hidden saved history.
A compact example
Suppose taps produce gaps of 500, 510, and 490 milliseconds. Their rates are 120, about 117.65, and about 122.45 BPM. Sorted, the middle value is 120. The displayed answer after the fourth tap is 120 BPM. The half-time candidate is 60 and the double-time candidate is 240.
Those candidates are arithmetic mirrors, not automatic recommendations. Context decides which pulse label is useful.
Three seconds starts fresh
If more than three seconds pass after the previous tap, the next activation begins a new sequence. The old gap is not converted into an extremely slow rate. The surface returns to an origin state and asks for another tap.
Reset clears the sequence immediately. Reloading or closing the page can also remove it because no persistent history exists.
Input choices
Pointer and touch suit direct visual interaction. Space and Enter work only when the tap area is focused. Keyboard auto-repeat is ignored, and a touch action must not also create a duplicate click. Choose the method you can operate consistently; the site does not rank input devices or people.
The large surface needs a visible focus ring, high contrast, an accessible name, and live status that does not steal focus. Reduced-motion preferences should remove unnecessary pulse animation without disabling the action.
What this page does not do
TapTempo.one does not listen to audio, request a microphone, read a file, fetch a URL, identify a song, connect to a deck, synchronize lighting, analyze a recording, or monitor keys outside its focused control. It has no API, account, database, analytics vendor, localStorage, sessionStorage, cookie, or persistent session history.
The page cannot verify meter, performance, cadence safety, musical correctness, or professional synchronization. A quick estimate should be checked with the appropriate independent system when consequences matter.
Why the result can move
A recent median reacts to the newest sequence. Press timing, input method, unclear pulse, source drift, and a short window can change the value. The median reduces the influence of one extreme compared with a mean, but it does not erase ambiguity.
If the answer jumps near a factor of two, revisit subdivisions. If it drifts gradually, the source or tapping may be changing. Reset and repeat over a stable passage.
A deliberate stopping point
The result is designed to be read, not chased. Once the recent value feels representative, stop tapping and note it with the pulse convention: for example, “about 96 BPM, quarter-note feel.” Continuing through a different section can answer a different question. Reset before the chorus, breakdown, or movement pattern becomes the new subject.
Frequently asked questions
Why wait until four taps for the main answer?
Four taps provide three intervals, enough to take a small recent median. A one-interval rate remains temporary.
Why use only eight intervals?
The compact window keeps the answer responsive and the product simple. It is not a claim that eight is universally sufficient.
Does the page save my BPM?
No. Active values stay in current-page memory and can disappear on reset, reload, timeout, or closure.
Is the half-time number wrong?
Not inherently. It expresses a slower pulse level at exactly half the displayed rate.
Open the tap tempo tool, focus the disc, follow one event for at least four taps, read the recent answer, and Reset before changing pulse level.