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What Is a Nonce, and Why Is My Transaction Stuck Behind Another?

What Is a Nonce?​

On Ethereum and other EVM networks (Base, Arbitrum, BNB Chain, Polygon, and others), every transaction from your address has a nonce: a counter that starts at 0 and goes up by one with each transaction you send. Your first transaction has nonce 0, the next has nonce 1, and so on.

The nonce does two jobs:

  • It keeps your transactions in order. The network only accepts nonce 5 after nonce 4 has confirmed.
  • It stops a transaction from being used twice. Each nonce can only confirm once, so nobody can replay a payment you already sent.

You can see a transaction's nonce on its block explorer page. See What Is a Block Explorer and How Do I Use It?.

Why Is My Transaction Stuck Behind Another?​

Because transactions from one address confirm strictly in order, a pending transaction blocks every later one. If nonce 4 is waiting, for example because its fee is too low for current demand, nonce 5 waits too, even if it pays a higher fee.

This usually happens when:

How Gem Wallet Picks the Nonce​

When you send, Gem Wallet asks the network how many of your transactions have confirmed and uses that count as the next nonce. You never need to set it yourself.

This means a second send from Gem Wallet, while your first one is still pending, usually gets the same nonce as the pending one. The network then does one of two things:

  • It rejects the new transaction, often with an error like "replacement transaction underpriced" or "nonce too low."
  • It replaces the pending transaction with the new one, if the new one pays a clearly higher fee. Only one of the two can confirm.
tip

Wait for a transaction to show Confirmed in Activity before sending the next one from the same address. That's the simplest way to avoid nonce problems.

What to Do​

  1. Find the blocking transaction. On the explorer, look at your address for the pending transaction with the lowest nonce.
  2. Wait for it to confirm or drop. Most pending transactions confirm once fees fall. If the network drops one, its nonce becomes free again, and later transactions can go through.
  3. Keep the network's fee coin in your wallet, such as ETH, so the pending transaction can still be included when fees allow.
  4. Don't keep resending the same payment. Check the explorer first, so you don't pay twice.

Gem Wallet doesn't currently offer Speed Up or Cancel for a pending transaction. See Why Is My Crypto Transaction Pending?.

Do Other Networks Use a Nonce?​

Many account-based networks use a similar counter, often called a sequence number, for example XRP Ledger and Cosmos chains. Bitcoin and other UTXO networks don't. They track coins instead of an account counter. Some networks, like Solana, use a recent block reference instead, so transactions don't wait in line behind each other.