Open interest: what it shows and how to read it in futures

Open interest: what is it and what does it measure?

Open interest is the total of derivative contracts that are still open right now. It doesn't count how many times a contract has been traded, it counts how many exist and have been neither closed nor expired. Every contract has two sides, a long and a short, and it is counted only once.

That's why it is a measure of participation. Rising open interest says there are more people in the market with an open position and more money committed. Falling open interest says positions are closing. It doesn't say who is right, and it doesn't say whether the newcomers are long or short: you only understand that by looking at the price too.

How is open interest calculated?

You don't need a formula, you need to follow who opens and who closes. An illustrative example, with made up numbers.

1. Anna opens a long of 10 contracts and Bruno opens the short on the other side. Open interest goes from 0 to 10.
2. Anna sells her 10 contracts to Carla, who opens a long. The position changes hands but nothing new is born: open interest stays at 10.
3. Bruno closes his short by buying 10 contracts from Carla, who closes her long. The two sides cancel out and open interest goes back to 0.

The rule in one line: open interest rises when two parties open, falls when two parties close, and doesn't change when a position passes from one person to another. Exchanges already publish it calculated, often updated in real time and for each contract.

What is the difference between open interest and volume?

Volume counts everything that is traded in a period, even if the same position changes hands ten times in the same minute. Open interest counts only what stays open. A day can have enormous volume and an almost unchanged open interest, if most traders get in and out quickly.

That's why the two numbers are read together. Volume tells you how much activity there is, open interest tells you how much position is still standing at the end. If you want to understand better who is long and who is short, the guide on long and short starts from zero.

How do you read open interest together with the price?

On its own, open interest tells you little. It becomes useful when you put it next to the price, because the four combinations tell different stories. They are readings of a trend, not rules: the same pattern can have opposite explanations.

Take the first row as an example. A rise with growing open interest is backed by new positions, but those positions are also new possible losses if the price turns. Open interest tells you how many people are on the boat, not whether the boat holds.

Is high open interest a risk?

It can be, especially when it grows together with leverage. The more positions with high leverage are open, the easier it is for a sudden move to wipe out many of them at the same moment: these are chain liquidations, which in turn push the price and cause others. You can find how the mechanism works in the guide to the leverage, and the calculator for the leverage shows you at what price the liquidation of one of your positions is triggered.

A concrete case: according to CoinDesk, in October 2025, when bitcoin hit its all time high at $126,000, open interest in bitcoin futures was around $94 billion. As the price fell, and as leverage was being swept away, it dropped. The big number hadn't prevented the fall, it was part of how it had formed.

How do you use open interest without being fooled?

Four habits, in order.

1. Always look at it together with the price. A number on its own tells you nothing.
2. Compare it with its recent history. The change over the last few days matters more than the absolute value.
3. Put it next to the funding rate. If open interest grows and the funding rate is very positive, the longs crowd one side and pay to stay there.
4. Don't turn it into a signal on its own. Decide your stop and position size before anything else, as the guide to the risk management.

The most common mistake is to read open interest as a forecast: «it rises, so the price will rise». It isn't one. It is a snapshot of how many positions are open right now, and a snapshot doesn't decide what happens next. If you are just starting out, the big picture is in the guide to mindful online trading.

Where STA fits in

Among the derivatives data that the STA agents read before every analysis there is also open interest, because it tells how crowded a direction is and how fragile a move may be. How they weigh it is part of the method we don't share. Ten artificial intelligence agents analyze the markets twice a day, with a debate between a Bull and a Bear, and the funds stay in your OKX account. The availability of contracts depends on the country where you live.

The DEMO is free forever, with real prices and the same cards as REAL. You need an account. During the launch phase, which began on 16 October 2026, STA's fees are temporarily disabled, even in REAL; the ordinary price list, suspended while the launch lasts, is 18% of the positive net result of each day, with no offsetting of losses. The history of the cards, losses included, is public on GitHub.

Frequently asked questions

This article is for information only and is not investment advice. Trading crypto-assets involves a high risk, including the total loss of the capital used. Numerical examples are for illustration.