Fee calculator.Mass and fee of a Kaspa payment.

Fee = fee rate × mass. The fee rate is quoted in sompi per gram and comes from the node's estimate of how busy the network is. The mass is measured in grams and is the larger of two numbers: the compute mass, which grows with the size of the transaction, and the storage mass, which grows when a payment creates small outputs.

A standard payment with one input and two outputs (the payment and your change) has a compute mass of 2,036 grams: 316 bytes of transaction data at 1 gram per byte, 72 bytes of output scripts at 10 grams per byte and one signature check at 1,000 grams. Every further input adds 1,118 grams, every further output 412.

A rule that makes very small outputs expensive, so the set of unspent coins that every node stores cannot be bloated cheaply. It is 10,000 KAS divided by each output amount, added up, minus the same for the inputs. Sending 1 KAS out of a 1,000 KAS coin gives about 10,000 grams — five times the compute mass — while sending 100 KAS gives almost none.

Wallets may add a margin, combine many small pieces into one first, use a different signature type, or use a fee rate from a few seconds earlier or later. This page calculates a standard single-signature payment at the rates it last read.

No. The mass is calculated in your browser; the page only loads the current fee rates and the KAS price.