What software can I use to calculate my private key from a seed (e.g. Trezor or Ledger)?

Any wallet software that allows restoring from a BIP39 mnemonic will allow you to do that, such as Electrum.

However, you should not do this on your regular computer, since putting your private key on your computer defeats the purpose of having a hardware wallet. If you really have to verify your key is correct, and you'd like to maintain the security of having a hardware wallet, do it from a computer that isn't connected to the Internet.