The Bitcoin network is designed to confirm transactions within 10 minutes, on average. If the transaction is not confirmed within that time frame, it is considered unconfirmed and will eventually be dropped by the network if it does not receive any further confirmations.

There are a few things you can do to try to speed up the process, but ultimately, it is up to the miners to include your transaction in a block and confirm it.

There are a few reasons why your transaction may be unconfirmed. The most common reason is that your transaction fee was too low or absent altogether. When you send a transaction, you include a fee that goes to the miner who includes your transaction in a block.

If you don’t include a fee, most miners will simply ignore your transaction. If you include a very low fee, your transaction may get stuck in a queue behind other transactions with higher fees.

Another common reason for an unconfirmed transaction is that it conflicts with another transaction in the blockchain. This can happen if you double-spent the same input in another transaction or if there was an accidental fork in the blockchain.

In either case, your transaction will eventually be dropped by the network if it is not confirmed.

If your transaction is unconfirmed and you want to try to speed up the process, you can use a service like ViaBTC’s Transaction Accelerator. This service allows you to submit your unconfirmed transaction ID and pays miners directly to confirm it faster.

Note that this is not a guarantee that your transaction will be confirmed; it is simply an opportunity to pay a higher fee to have your transaction included in the next block.

Ultimately, there is no guaranteed way to cancel an unconfirmed Bitcoin transaction. If your transaction has been unconfirmed for hours, it is likely that it will eventually be dropped by the network.

However, if you still want to try to cancel your transaction, you can use a service like ViaBTC’s Transaction Accelerator. This may give your transaction a better chance of being included in the next block and confirm faster.