# unit_mismatch (/docs/errors/unit-mismatch)

Two amounts denominated in different currencies were combined.

Every Balance carries the netuid whose currency it denominates: netuid 0 is TAO, any other netuid is that subnet's alpha. arithmetic between different netuids raises instead of silently mixing currencies, because 1 alpha on one subnet is not worth 1 alpha on another.

Construct the amount in the operation's own currency: Balance.from\_tao for TAO, Balance.from\_alpha(amount, netuid) for a subnet's alpha.

## Remediation [#remediation]

Match the Balance netuid to the operation's currency

## Chain errors [#chain-errors]

No chain error classifies to this code — it is raised client-side by the SDK before or after the call reaches the chain.

The same explanation is available in the terminal: `btcli explain unit_mismatch` (or `btcli explain <ChainErrorName>` for one exact chain error).