Bitcoin transaction stuck with a low fee
A low-fee Bitcoin transaction sits at the back of the mempool because miners fill blocks with the highest-paying transactions first. The fix is to raise the effective fee rate so your transaction jumps the queue.
RBF (Replace-By-Fee). If you enabled RBF when you sent the transaction, broadcast a replacement that spends the same inputs and pays a higher fee. The network drops the low-fee original and relays the better-paid replacement.
CPFP (Child Pays For Parent). If RBF is not available, create a new transaction that spends one of the stuck transaction's outputs and pays a high fee. Miners confirm both together, effectively boosting your stuck transaction's fee rate.
How much to add. Raise the effective fee rate to (or just above) the current 'fast' threshold shown on a fee estimator. That is usually enough to land in the next block.
Quick answers
RBF or CPFP — which should I use?
Use RBF if the original was broadcast with RBF enabled — it is simplest. Use CPFP when RBF is not available; it works by paying for the parent from a child transaction.
How much extra fee do I need?
Enough to push the effective fee rate to or above the current fast threshold. Check a fee estimator and add just enough to clear it.
Can I send another transaction while one is stuck?
You can send a transaction that does not spend the stuck transaction's outputs. But you cannot double-spend the same coins until the stuck transaction confirms or is replaced.