MAEXO

What is a blockchain confirmation?

Guide

Crypto practical4 min

What is a blockchain confirmation?

A confirmation is one block added to the chain on top of the block containing your transaction. Each extra confirmation makes reversing the transaction exponentially harder, which is why exchanges wait for several before crediting a deposit.

From broadcast to confirmed

When you send a transaction it first enters the mempool — a waiting room of unconfirmed transactions. A validator picks it up and includes it in a block. That inclusion is confirmation one. Every subsequent block is another confirmation.

  • 0 confirmations — broadcast, in the mempool, reversible
  • 1 confirmation — included in a block
  • 3–6 confirmations — treated as settled by most services

Why more confirmations mean more safety

Rewriting a block requires redoing all the work stacked on top of it. Each additional block multiplies that cost, so the practical probability of a reversal drops away quickly. This is why high-value transfers wait longer than small ones.

Example

Bitcoin averages a block roughly every 10 minutes, so six confirmations is about an hour. Many chains finalise in seconds, which is why deposit times differ so much between assets.

Why your deposit is still pending

  • Fee too low — the transaction is sitting in the mempool
  • Network congestion pushing out block space
  • Exchange requires more confirmations than the chain has produced
  • Transaction sent on a different network than expected

Speeding things up

Some wallets support replace-by-fee, letting you rebroadcast the same transaction with a higher fee. Where that is unavailable, the only option is to wait — congestion clears, and low-fee transactions eventually get included or are dropped and returned to your wallet balance.

Halving countdown

See how block timing drives the Bitcoin supply schedule.

FAQ

Common questions

How many confirmations is safe?

It depends on value and chain. Small transfers are usually fine at one to three; large transfers on proof-of-work chains are commonly held to six.

Can a confirmed transaction still fail?

A confirmed transfer will not be undone, but a smart-contract transaction can confirm and still revert internally, consuming the fee without completing the action.

Why is my transaction stuck at zero confirmations?

Almost always an under-priced fee during congestion. Wait, or rebroadcast with a higher fee if your wallet supports it.

Related

Read next

Latest Bitcoin news

HIGH RISK WARNING: Trading Forex and leveraged derivative products (CFDs) or crypto involves significant risk and is not suitable for all investors. Leverage magnifies both gains and losses. You do not own or have rights to the underlying assets. You may lose all your invested capital; never speculate with funds you cannot afford to lose. Information on this site is general and does not constitute personalized financial advice. Past performance does not guarantee future results. Please ensure you fully understand the risks and review our legal documents section.