How to speed up a pending Ethereum transaction
Speeding up a slow Ethereum transaction means re-sending the same transaction with a higher gas fee so validators include it sooner. The replacement must reuse the original nonce and raise the fee by at least 10% to be accepted into the mempool.
The 10% rule. Under EIP-1559, a replacement transaction is only accepted if it raises the max fee per gas and the max priority fee per gas by at least 10% above the original. A smaller bump is silently ignored by the network.
How much to raise it. Check a live gas tracker for the current fast price, then set your replacement's fee a little above it. During fee spikes a 10% bump over the original may still be below demand — in that case bump again.
When it helps. Speeding up works only while the original is still pending. If the original confirms first, there is nothing left to speed up.
Quick answers
Why did my Speed Up not work?
Most often the bump was under 10%, or the new fee was still below current network demand. Raise the fee to (or just above) the current fast price and resend.
How much does it cost to speed up a transaction?
You pay the gas of the replacement transaction. The difference is only the extra fee you added over the original — usually a few dollars at normal gas prices.
Is there a maximum number of times I can speed up?
You can replace a pending transaction repeatedly, each time raising the fee. The most recent, highest-fee replacement is the one that gets mined.