The answer depends on which client you are running. As of April 2021 an Ethereum full node needs:

• ~732GB for Geth (Go)
• ~411GB for OpenEthereum (Rust)

This answer will of course become outdated, please refer to my source for these numbers here:

Source: https://etherscan.io/chartsync/chaindefault

The answer depends on which client you are running. There are more than 6 different implementations, but below are 2 for reference:

As of April 2021:

• ~732GB for Geth (Go)
• ~411GB for OpenEthereum (Rust)

This answer will of course become outdated, please refer to my source for these numbers here:

Source: https://etherscan.io/chartsync/chaindefault

Other implementations:

• Nethermind (C#)
• Turbo Geth (Go)
• Besu (Java)
• Sentry (Rust)