How big should my channels be?

This is one of the most common questions for new node runners.

Bigger is better

As we learned in How much does it cost to open a lightning channel, the cost of opening a channel is NOT related to the size of the channlel.

A big channel will "tie up" more of your Bitcoin, meaning, you won't be able to use it outside the channel, but a big channel also has these beneficial characteristics:

1. More payments can be sent through the channel in one direction until that direction is "exhausted".
2. Because more payment can be sent through the channel, you have a greater chance of recouping the opening (and closing) fee.
3. Larger payments are able to flow through the channel.
4. Certain payers on the Network might prioritize your large channel above other, smaller ones.

What about MPP?

If you've done other learnings on Lightning, you might have heard of MPP: "Multi-path payments".

With MPP, the payment sender "breaks up" one payment, and sends it to its destination via multiple routes.

MPP is supported by the node Implementations, but it has a significant caveat.

There is an time limit specified in Bolt #4.

This means that really big MPP payments, when forced through tiny channels, might "time out" before the payment is complete.

This is not a good experience for users, so some paying nodes might prefer to send a payment "all at once", instead of relying on MPP.

For this reason, a bigger channel is still better for payment reliability, even given the possibility of MPP.

So how big should my channels be?

A good starting point, for the first few channels you open, is 0.05 BTC. This is small enough to allow you flexibility for future channel opens, but big enough that you should be able to send substantial payments through the channel.