Lightning Routing Fee Calculator: Base Fee and PPM

Lightning Network Routing Fee Calculator

Lightning payments travel through channels of other nodes, and each forwarding node charges a small fee made of two parts: a fixed base fee in millisatoshis and a proportional fee in parts per million. Build a route of up to eight hops to see what each one charges, the total in sats and dollars, and how it compares with paying on chain.

#	Fee, msat	Fee, sat
1	11,005	11.005
2	50,000	50
3	1,100	1.1

Fee, msat

Fee, sat

11,005

11.005

50,000

1,100

1.1

How a hop's fee is computed

BOLT 7 defines a channel's fee as fee_base_msat + amount × fee_proportional_millionths / 1,000,000, applied to the amount the node forwards. Because every hop forwards the payment plus the fees of the hops after it, the sender's wallet computes fees from the destination backwards. This calculator does the same.

hop fee (msat) = base_fee_msat + forwarded amount (msat) × ppm ÷ 1,000,000
forwarded amount of hop k = payment + fees of hops k+1 … n
1 sat = 1,000 msat

Typical values

Many nodes set the base fee to 0 or 1,000 msat (1 sat) and the rate between 1 and a few thousand ppm; popular routing nodes adjust them to balance their channels. For a 100,000-sat payment over three hops the total is often a few sats to a few hundred sats. Wallets search for a cheap route and show the fee before you confirm.

Lightning or on-chain

Small and frequent payments: Lightning fees are usually far below on-chain fees, and the payment settles in seconds.
Large amounts: the proportional fee grows with the amount, and a route needs enough channel liquidity; on-chain may be simpler.
Exchanges and swap services that ask for a Bitcoin address need an on-chain payment. KOT.CASH swaps use on-chain BTC; Lightning invoices are not accepted as deposits or payout addresses.

Frequently asked questions

+What does ppm mean in Lightning fees?

Parts per million of the forwarded amount. 1,000 ppm is 0.1%; on 100,000 sats it is 100 sats.

+What is base_fee_msat?

A fixed fee per forwarded payment in millisatoshis. 1,000 msat equals 1 sat.

+Do I pay a fee to my own channel partner?

The first hop from your own channel does not charge you a routing fee; fees are paid to the nodes that forward your payment further.

+Can I send Lightning to a KOT.CASH swap?

No. Swaps accept and pay out on-chain Bitcoin. Send from an on-chain wallet or move funds off Lightning first.

Calculations run entirely in your browser; nothing you type is sent to KOT.CASH. Results are estimates for information only and are not financial, tax or legal advice.