If you don't care about your privacy, you can always find the associated extended public key (xpub*) and enter it in a blockchain explorer site such as https://www.blockchain.com/explorer.

Here is how a Bitcoin account's (M/44'/0'/0'/) extended public key for a given set of 12 seed words can be computed on a trusted air gapped offline computer that could be operating in a Faraday cage:

% echo "radar blur cabbage chef fix engine embark joy scheme fiction master release" | bx mnemonic-to-seed | bx hd-new | bx hd-private -d -i 44 | bx hd-private -d -i 0 | bx hd-public -d -i 0 xpub6DHi64TFkDPx2AH4q2ku3vX9LJYNpTis5tLrET8Sb9irp174eCkgtAnvBpyzQXgrtmF31Lrq4gTMGFUGcjJicMu9LdueVdqt6FZ2Wzcg8Fj

Ledger and Trezor devices can be queried to gain access to your xpub key.

Otherwise, just apply the KISS principle and use your wallet application that will naturally provide you with an account balance.