Ethereum's Ethereum Virtual Machine (EVM) is a 256-bit stack machine that executes bytecode deterministically across every node. Unlike Bitcoin's limited Script, the EVM is Turing-complete, meaning it can run arbitrary logic — but only if execution is bounded by gas.

Every opcode consumes a fixed amount of gas, and the EVM halts when gas runs out. This prevents infinite loops and denial-of-service attacks.

Stack: up to 1024 items, 256-bit words
Memory: volatile, byte-addressable, expands quadratically in cost
Storage: persistent key-value store, expensive to write (20,000 gas per SSTORE)
Calldata: read-only input data, cheap to read (3 gas per byte)

Component	Cost Profile	Persistence
Stack	3 gas (very cheap)	Per call
Memory	3 + quadratic expansion	Per call
Storage	20,000 gas write	Permanent
Calldata	16 gas non-zero byte	Per transaction