BTC up or down, five minutes

Five minutes is the standard window for a short-dated Bitcoin market, and the one every round here runs on. This page is what that window actually is: where it starts, what Bitcoin does inside it, and what a side of it is worth while the clock runs.

The window is a candle, not a timer

A five-minute market could be built two ways. It could start a five-minute clock the moment you arrive — your window, nobody else's — or it could use a window the whole world already shares. This one does the second: a round is one BTCUSDT candle on Binance, on the exchange's own grid. Rounds open at :00, :05, :10, :15 and run to the next mark.

• The candle's open is the price to beat.
• Its close decides the round: Up above the open, Down below it.
• An exact tie refunds every bet.
• Betting stops ten seconds before the candle closes, for everybody at once.

The difference matters more than it sounds. A private five-minute timer is a number only the house can produce; a shared one is published by an exchange, drawn on every chart in the world, and checkable in a single request by anyone who wants to argue with the result.

What five minutes of Bitcoin looks like

Worth knowing before you pick a side, and rarely written down anywhere. Measured over the 3,000 five-minute BTCUSDT candles from 11 to 21 September 2026 — ten and a half days, BTC around $84,700:

So a typical round is decided by about forty dollars, and about one round in a hundred and ninety is decided by nothing at all and hands everyone their stake back. The 52.1% leaning Up over ten days is the kind of number that looks like a signal and is mostly the fortnight it was measured in — nothing here prices off history anyway, only off where the price is right now.

What a side costs while the five minutes run

A side is a share that pays 1.00 if it wins. It costs its chance of winning plus a 3¢ spread, and the chance comes out of how far the price already sits from the price to beat against how long is left:

d      = ln(price / price to beat) / (σ · √seconds left)
chance = Φ(d) for Up, Φ(−d) for Down
share  = chance + spread
pays   = 1.00 / share

At the start of a round nothing has happened yet, d is zero, and both sides cost 53¢ and pay 1.8867×. After that the five minutes do the work. That same forty-dollar move — the median one — is worth this much depending on when in the round it happens:

Which is the whole texture of a five-minute market: a side that falls behind early is cheap and pays multiples if the last minutes turn, and a side that is nearly decided stops being worth buying. Past 99¢ a side is not sold at all, and nothing pays more than 10×. The two sides add to more than the 1.06 an even round costs, and visibly so once a round leans — that is σ being moved against both of them, which is the guard below, and it is counted in the published margin.

σ is recent volatility, estimated from the exchange's own candle ranges and kept current from live trades, and it is moved 20% against whichever side is being priced so that a bad estimate cannot be picked off for free. The full mechanism is on its own page, and what the spread earns is on another.

The same window, priced two different ways

Five-minute BTC markets also run on Polymarket, Kalshi and Limitless, and they are a different kind of thing under the hood. Those are markets you trade in: your side is priced by whoever is willing to take the other one, the price is whatever the book says, and you can usually sell out before the window closes.

Here there is no book. A side is priced by the model above plus a published spread, it fills instantly at the number printed on the button, and a bet is settled rather than sold — you take a side and the candle decides it. That is simpler and faster, and it costs a margin that an order book does not charge you in the same way; the size of that margin is published in full rather than left for you to work out.

Checking a five-minute round

One request, no API key, from any terminal:

curl "https://api.binance.com/api/v3/klines?symbol=BTCUSDT&interval=5m&startTime=OPEN_TIME&limit=1"

Field 1 of the array that comes back is the open — the price to beat — and field 4 is the close, which decided the round. Both must match what was published. Every settled round is listed in the archive, by day, with its open time; the worked example is here.