How to Track Crypto Profit and Loss (P&L) Accurately
Methods for calculating real crypto P&L including unrealised gains, cost basis tracking, and why exchange P&L numbers can be wrong.
Knowing your true profit and loss is harder than it sounds in crypto. Exchange dashboards often show incomplete or misleading numbers, and without proper tracking, you might think you are profitable when you are not — or vice versa.
Why exchange P&L is unreliable
Most exchanges only show your P&L for trades made on their platform. They do not account for tokens you deposited from external wallets, assets you bridged to other chains, DeFi yields, or gas fees spent on-chain. If you bought ETH on Coinbase, bridged it to Arbitrum, and swapped for tokens on a DEX, Coinbase has no visibility into your actual position.
Cost basis matters
Your true P&L depends on your cost basis — what you originally paid for each token. If you bought Bitcoin at different prices over time (which most people do), your average cost basis determines your real gain or loss. Simply comparing today's price to your most recent purchase price is misleading.
Unrealised vs realised P&L
Unrealised P&L is the profit or loss on tokens you still hold — it represents what you would gain or lose if you sold at current prices. Realised P&L is the profit or loss on tokens you have already sold. For tax purposes, only realised P&L matters. But for portfolio management, unrealised P&L tells you where you stand right now.
Including all costs
A complete P&L calculation must include: the original purchase price (including any exchange fees), gas fees for on-chain transactions, bridge fees, DEX swap fees, and any other costs incurred in acquiring or disposing of the token. Many people forget gas fees, which can be significant on Ethereum mainnet.
The GBP factor
For UK investors, there is an additional complexity: crypto prices are usually denominated in USD, but your tax liability is in GBP. Exchange rate fluctuations mean your GBP P&L can differ from your USD P&L. A token might be flat in USD terms but up in GBP terms if the pound weakened, and vice versa. Always track P&L in GBP for tax purposes.
CryptoLens calculates your true P&L across all chains, including gas fees and GBP conversion, giving you an accurate picture of where you actually stand.
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