I suspect there are many folks with the same dilemma, so I’m going to drop a spoiler on you, you fellow netkin that don’t enjoy interacting with people:

The Interweb isn’t much help here.

Your best bet is to either look at the first set of numbers in the lower left of one of your checks (between the multiple |: shapes) or to give in and take care of it like it’s 1985. That involves picking up the phone and enduring some personal interaction with a bank customer service agent.

I know, I know. Daunting prospect.

In case you’re interested in how these numbers aren’t randomly thrown together, feel free to investigate the wikipedia entry on Bank Routing Numbers. Stirring stuff.

Good day.