An exchange does not pick the price
On most crypto exchanges, nobody sits down and decides what a coin is worth. The platform provides a place where buy and sell instructions meet, and the price is simply the level at which the most recent trade happened. If buyers become more eager, they accept higher asking prices and the quote rises. If sellers become more eager, they accept lower bids and it falls.
That is why the price you see on a screen is best understood as a record of agreement between two people (or programs) at one moment, on one venue. It is not an official value handed down from anywhere. Cryptocurrency trades around the clock and across many independent venues, so there are many such records at once, and they are rarely identical.
Where the quoted price comes from
Most large centralized exchanges run a matching engine. It keeps a list of resting buy orders (bids) and sell orders (asks), and when a new order can be paired with one on the other side, a trade happens. The displayed “last price” is the price of that trade. Many platforms also show a best bid and best ask, which are the highest price someone will pay and the lowest price someone will accept right now.
The gap between those two numbers, and the quantity waiting at each level, shape what you actually pay. A quick market purchase can end up filling above the last price if the best ask is not large enough for your size. The mechanics of reading those resting orders are covered in the article on the order book, and the cost of crossing the gap is the subject of the bid-ask spread.
Some venues, particularly on-chain ones, do not use a list of orders at all. Instead a formula based on the amounts held in a pool sets the price, which is covered in the article on automated market makers. The principle is the same, though: the price comes from the balance of supply and demand at that venue, not from a decision by its operator.
Why the same coin trades at different prices
If you compare two exchanges at the same instant, you will often see small differences. Several ordinary reasons explain this.
- Different participants. Each venue has its own mix of traders, with different sizes, strategies and urgency. Buying pressure on one platform may not be matched on another at that exact second.
- Different liquidity. A venue with plenty of orders close to the market price absorbs trades with little movement. A thinner venue shifts more for the same order, so its quote can wander further from others.
- Different quote currencies. One venue may price a coin against US dollars, another against a dollar-pegged token, another against euros. Each of these has its own supply and demand, and a stablecoin can trade slightly above or below one dollar. This is part of why crypto prices are quoted against dollar tokens, and it can produce a persistent small gap that is not a mistake.
- Fees and costs. Trading fees, withdrawal fees and network charges mean that the price you see is not the price you net. A gap smaller than these costs may simply not be worth acting on.
- Access frictions. Some venues are hard to reach because of regional rules, identity checks, or limits on moving money in and out. When capital cannot flow freely, price gaps can last longer. Fiat on-ramps and differences between jurisdictions both play a part.
- Timing. Prices update continuously, and a screenshot or data feed is always slightly old. Two sources can look different just because they were sampled a moment apart.
What keeps prices roughly aligned
Traders who watch several venues can try to profit from gaps by buying where a coin is cheaper and selling where it is dearer. This is called arbitrage. Their buying pushes the cheaper price up and their selling pushes the dearer price down, which tends to pull venues back toward each other.
Arbitrage is not free or risk-free, though. It requires capital on more than one platform, it incurs fees, and moving coins between venues takes time during which prices may change. When transfers are slow or blocked, or when markets move quickly, gaps can widen and persist for longer than people expect. During sharp swings, differences between venues often become more noticeable. Because price volatility is a feature of this market, a small gap in calm conditions can become a large one in turbulent ones.
Why there is no single “true” price
Because each venue is its own market, there is no single authoritative number. Data websites handle this by combining quotes from many venues into one reference figure, using rules about which sources to include and how to weight them. That process is described in the article on price aggregation, and the choice of method means that two aggregators can show slightly different values for the same coin at the same moment.
Likewise, the price on a chart is usually the price from one specific source. A chart labelled with a particular exchange and pair (for example a coin against US dollars) reflects that market only. If you place a trade on a different platform, your fill may differ from the chart you were looking at.
Things worth knowing before you trade
- The price you see is not guaranteed. For a market order, the final fill depends on what is resting in the book when your order arrives. The difference between the expected and actual price is called slippage, and it is larger for bigger orders and thinner markets.
- Volume figures vary. The activity numbers shown next to a price are not audited in a uniform way across venues, and some figures are known to be unreliable. That is the subject of the article on trading volume.
- Venue risk is separate from price risk. A platform can be unavailable, restricted or fail, regardless of what the price is doing. This is the kind of counterparty risk that applies when you leave coins on an exchange.
- Low-quality venues can show unusual quotes. If one platform shows a price far from the rest, that is more likely a sign of thin trading or an operational problem than a bargain.
Cryptocurrency prices are volatile, past behaviour does not predict future results, and it is possible to lose everything you put in. Nothing here is financial, tax or legal advice; it is a general explanation of how quoted prices come about.
A short mental model
Think of each exchange as a separate marketplace in a different town. The goods are the same, but each town has its own crowd, its own rules, and its own local currency preferences. Merchants who can travel between towns keep the prices from drifting too far apart, but they cannot erase every difference, because travel takes time and costs money. The “price of Bitcoin” you hear quoted is a summary of what is happening across all those towns, not a single posted tag.