A web based interface to the Bitcoin API JSON-RPC

Command: estimatefee

The estimatefee RPC estimates the transaction fee per kilobyte that needs to be paid for a transaction to be included within a certain number of blocks.

Parameter #1—how many blocks the transaction may wait before being included
Result—the fee the transaction needs to pay per kilobyte

The maximum number of blocks a transaction should have to wait before it is predicted to be included in a block.
estimatefee nblocks

Estimates the approximate fee per kilobyte needed for a transaction to begin
confirmation within nblocks blocks. Uses virtual transaction size of transaction
as defined in BIP 141 (witness data is discounted).

1. nblocks     (numeric, required)

n              (numeric) estimated fee-per-kilobyte

A negative value is returned if not enough transactions and blocks
have been observed to make an estimate.
-1 is always returned for nblocks == 1 as it is impossible to calculate
a fee that is high enough to get reliably included in the next block.

> bitcoin-cli estimatefee 6