Nonce
Definition
A nonce is a per-account counter of sent transactions on Ethereum, ordering them sequentially and preventing the same transaction from being replayed.
On Ethereum, each externally owned account has a nonce: a counter of how many transactions it has sent, starting at zero. Every new transaction from that account must carry the next sequential nonce. The network processes an account’s transactions strictly in nonce order and rejects a nonce it has already seen, which is what stops the same signed transaction from being executed twice.
Why it matters
The nonce provides ordering and replay protection at the account level. It is also why a transaction can get “stuck”: if a transaction with nonce 5 is pending with too low a fee, later transactions with nonces 6, 7, and so on cannot be processed until nonce 5 clears. Users resolve this by replacing the stuck transaction, resubmitting the same nonce with a higher fee. Signed permits under EIP-2612 use their own separate nonces for the same anti-replay purpose.
Common misunderstanding
People sometimes think the nonce is a random or cryptographic value like the “number used once” in other security contexts. In Ethereum’s account model it is simply a sequential counter. Another misconception is that you can skip a nonce to jump ahead; you cannot, because the network requires them in order. Understanding this makes stuck-transaction situations far less mysterious and explains why cancelling usually means replacing a specific nonce rather than deleting a transaction outright. Most wallets handle nonces automatically, so you usually only encounter the concept when a low-fee transaction leaves later ones waiting.
Related terms
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