What did your wallet hold on the cut-off date?

For a tax return the balance on 31 December counts, not today's. This tool reads it at the matching block straight from the chain: ETH and every ERC20 token, with block number and block hash as a proof that any archive node confirms.

One address or ENS name, one date: free and without sign-up. Ethereum mainnet only: ETH and ERC20 tokens, no NFTs. No euro valuation and no statement on taxability: chain facts, nothing more. The address is sent to the node provider for the lookup and is not stored.