About

Accurately estimating Bitcoin transaction fees is critical to preventing stuck transactions or overpayment. This tool interfaces directly with the Mempool to provide real-time fee rate recommendations based on current network congestion. Unlike simple estimators, this utility calculates the exact Virtual Size (vBytes) of your transaction by accounting for address types (Legacy, SegWit, Taproot) and complex input/output configurations.

Network fees are determined by block space demand, not transaction value. A $10 transaction can cost as much as a $1,000,000 transfer if they consume the same block weight. Use the Advanced Calculator below to model complex scenarios like UTXO consolidation or Multisig vault movements.

Formulas

The total cost of a Bitcoin transaction is a function of its data footprint (weight) and the market rate for block space.

Feetotal = Ratesat/vB × (Ninputs × Winput + Noutputs × Woutput + 10.5)

Where 10.5 represents the fixed transaction overhead in vBytes. The Virtual Byte size differs from raw size due to the Segregated Witness discount:

SizevB = Sizebase × 3 + Sizetotal4

Reference Data

Address Type	Standard	Input Weight (vB)	Output Weight (vB)	Efficiency Score
Legacy (P2PKH)	Original (1 starts)	148.0	34.0	LOW
Nested SegWit (P2SH)	Wrapper (3 starts)	91.0	32.0	MEDIUM
Native SegWit (Bech32)	Modern (bc1q starts)	68.0	31.0	HIGH
Taproot (P2TR)	Privacy (bc1p starts)	57.5	43.0	MAX
Multisig (2-of-3 SegWit)	Vault/Security	104.5	31.0	Variable

Frequently Asked Questions

If you set a fee lower than the current network clearing rate, miners will deprioritize your transaction. It remains in the "Mempool" until fees drop or it is evicted (usually after 14 days). You can speed it up using RBF (Replace-By-Fee) or CPFP (Child-Pays-For-Parent).

Satoshis per Virtual Byte. This is the unit of price for block space. 1 Bitcoin = 100,000,000 Satoshis. "Virtual Byte" is a weight unit that accounts for the SegWit discount, making witness data (signatures) cheaper than base transaction data.

No. Sending 0.001 BTC costs exactly the same as sending 1,000 BTC if the transaction structure (inputs/outputs) is identical. The fee depends entirely on the data size, not the value transferred.

Historically, the Bitcoin network is less congested during weekends (Saturday/Sunday) and late nights in North American time zones. This tool's historical indicator can help identify these windows.