Calculating the right Bitcoin fee requires knowing the current network demand and the size of your transaction. Our fee estimator pulls live mempool data to show you exactly how many satoshis per virtual byte you should attach to your transaction for fast, medium, or economy confirmation times.

Formula: How to Calculate Your Transaction Fee

Transaction size depends on the number of inputs and outputs. For a standard non-SegWit transaction, the formula is: Size (bytes) = (inputs × 148) + (outputs × 34) + 10. A SegWit (P2WPKH) transaction is cheaper: inputs cost ~68 vB instead of 148 bytes. Always use SegWit addresses to reduce costs. Multiply your calculated vB size by the current sat/vB rate to get the total fee in satoshis.

Bitcoin fee tiers typically fall into three catego...

Bitcoin fee tiers typically fall into three categories: Fast (next 1–2 blocks, ~10–20 minutes), Medium (within 3–6 blocks, ~30–60 minutes), and Slow (within 24 blocks, several hours). During periods of low network activity, fees can drop to as low as 1 sat/vB. During high congestion — such as bull market surges or inscription crazes — rates can spike above 200 sat/vB. Always check mempool.space or a live fee API before sending a time-sensitive transaction.

• Fast tier: 1–2 block confirmation
• Medium tier: 3–6 blocks
• Slow tier: next 24 blocks
• SegWit saves ~40% on fees

SegWit vs Legacy →