Open interest in one sentence
Open interest (OI) is the total size of futures positions that are open right now: contracts that have been opened and not yet closed, settled or liquidated. On crypto exchanges it is usually quoted for perpetual futures, either in coins (contracts) or in US dollars.
Every futures contract has two sides. When a new buyer and a new seller trade with each other, one long and one short position appear and open interest rises by that size. When a trader closes a long by selling to someone who is closing a short, both positions disappear and OI falls. When one side is only handing its position to a new trader, OI does not change at all, even though volume was traded. That is why OI and volume measure different things: volume counts activity, OI counts what is still at stake.
How exchanges report it
Binance, Bybit and Hyperliquid all publish open interest per market through their public APIs. Binance and Bybit report it in contracts (for most USDT-margined perps, one contract is one coin), and Hyperliquid reports it in the coin as well. This site multiplies it by the price to get a USD figure, polls every market, and sums it per coin across exchanges on the open interest page.
USD open interest has one trap: it moves with price. If BTC rises 5% and nobody opens or closes anything, BTC open interest in dollars still rises 5%. To see whether positions were really added, take the price move out: a 7% USD OI rise during a 5% rally is only about 2% more contracts. The open interest screener does this before it labels a move, and the live box above shows both numbers for BTC.
Reading OI together with price
Open interest on its own has no direction. Every long has a matching short, so rising OI does not mean traders are bullish; it means more money is committed to the market on both sides. The useful signal comes from pairing the OI change with the price change over the same window:
- OI up, price up: new longs. Buyers are opening positions and paying up to do it.
- OI up, price down: new shorts. Sellers are opening positions and pushing price lower.
- OI down, price up: short covering. Shorts are closing (or being liquidated) by buying back.
- OI down, price down: long unwinding. Longs are closing (or being liquidated) by selling.
These labels describe who was the aggressive side, not what happens next. A rally made of new longs can continue, or it can reverse sharply if those late longs are forced out. Add funding to the picture: when OI climbs and funding is also high, longs are crowded and paying for it; when OI climbs with negative funding, shorts are the crowded side.
Why traders watch it
Leverage build-up. A fast rise in OI without much price movement means leverage is piling in. Leverage has to be unwound at some point, and when it unwinds all at once you get a cascade of liquidations and a large candle.
Confirmation. A breakout on rising OI is backed by new positions; a breakout on falling OI is mostly shorts covering, which can run out of fuel once they are done.
Flushes. A sharp drop in OI during a sell-off shows positions being closed or liquidated. After a large flush, the market often carries less leverage than before.
Relative size. Comparing OI with daily volume or market cap shows how much of a coin's trading is leveraged. Small coins with OI close to their daily spot volume can move violently when positions unwind.
Limits to keep in mind
- OI is per exchange. A move on one venue can be traders moving between exchanges rather than new positions; summing venues, as the BTC open interest page does, reduces that.
- OI does not include spot holdings, options or positions on exchanges we do not track, so it is a partial view of total leverage.
- Our 1h, 4h and 24h changes come from 5-minute snapshots this site records. After a server restart the longer windows show "collecting history" until enough data exists.
- Hedged positions count too: a fund that is long spot and short perps adds to OI without a directional bet.
Used with price, funding and liquidations, open interest tells you how crowded a market is and which side is under pressure. It does not tell you where price is going. For the biggest moves right now, see the screener or Hyperliquid open interest.
Checked against the exchanges' own documentation on 28 September 2026: Binance API: open interest. Not financial advice.