Definition
In a trading pair, the base currency is the asset being priced. “Currency” here can refer to a cryptocurrency or token, not only government-issued money. Its role is defined by the pair rather than being a permanent property of the asset.
How It Works
For BTC/USDT, BTC is the base and the displayed price is USDT per BTC. A hypothetical purchase of 0.1 BTC at 50,000 USDT per BTC has a value of 5,000 USDT before fees. BTC becomes the quote asset in ETH/BTC, showing that the same asset can serve either role.
Key Considerations
Do not confuse base quantity with total order value. Trading forms may accept either quantity or spending amount, and their units must be checked. A platform’s account reporting currency or the Base blockchain is a separate concept and need not match the trading pair’s base currency.