PLAY FREE ▶

About BTC Up/Down

By Matthew Rhodes · Last updated

BTC Up/Down is a free Bitcoin Up or Down simulator made by Matthew Rhodes. This page explains who's behind it, how its prices are calculated and where the information in the guides comes from.

About BTC Up/Down

BTC Up/Down is made by Matthew Rhodes, a former sell-side analyst and financial journalist who writes about markets and probability. Questions, bug reports or ideas are welcome: message @HighDividendETF on X.

BTC Up/Down is an independent, free Bitcoin Up or Down simulator built for people who want to understand short-term prediction markets before risking money on them. It runs entirely in your browser: there are no accounts, your balance and history stay on your device, and prices come straight from public exchange feeds. It is not affiliated with any exchange or prediction market, and nothing on this site is financial advice.

Why BTC Up/Down isn't a casino

BTC Up/Down is a learning tool, not a gambling product. There's nothing to deposit, nothing to withdraw, no prizes, no house edge and no casino or broker affiliate links. Your $1,000 is play money with no cash value. That makes it suitable for parents, teachers, trading clubs and anyone wary of gambling sites who still wants to understand how fast Bitcoin markets behave.

Methodology: how BTC Up/Down prices each round

BTC Up/Down prices UP with a standard fair-value model: the chance that Bitcoin's price ends above the price to beat, given how far away it is, how long is left and how volatile it has been.

  • Volatility: measured from the last five minutes of 1-second Bitcoin returns, updated twice a second.
  • Fair UP probability: Φ( ln(price ÷ price to beat) ÷ (σ × √seconds left) ), where Φ is the normal distribution.
  • Quotes: a 2¢ spread around fair value, rounded to whole cents between 1¢ and 99¢. DOWN mirrors UP.
  • Close: betting stops one second before the end. The round settles on the last live trade price, and ties go to UP.
  • Void rounds: if the feed goes quiet or switches exchange mid-round, the round is voided and bets are refunded at cost.

The model treats short-term moves as random, which is a reasonable first approximation for Bitcoin over minutes. Real markets add the views of every trader in them, so their prices can drift away from this fair value.

Trade responsibly

Short-term markets move fast and can be compulsive. If you go on to trade real Bitcoin Up or Down markets, set a budget you can afford to lose, decide your limits before you start, and take breaks. Losing streaks are normal in markets this close to random. If trading stops being fun or starts affecting your money or mood, stop and talk to someone you trust.

Sources and further reading