Grounds-to-water in a large coffee urn

This weekend I’m in charge of the coffee at a community event. The facility has two 100-cup coffee urns. My question is, how many cups of coffee grounds will it take to make a decent urnful?

Electric, no filter, spout at the bottom of a cylinder that holds 100 cups. That’s about all I know. Any coffee gurus (or people who’ve spent a lot of time in church basements) able to help me?

Thanks in advance,

If your coffee comes in a “three pound” can (or more commonly now, a plastic tub) that’s roughly the size of a gallon paint can, use half a can per 100-cup pot. The actual weight is closer to 2 and a half pounds after the coffee industry shrank a pound can from 16 to 13 ounces several years ago.

These containers claim to make 240-270 “cups” of coffee, so half of one will be 120-135 “cups” - a “cup” of coffee is actually six ounces. And people rarely complain much if the coffee is a bit strong - they’re just put in some more cream, if anything. But if you serve weak coffee, watch out.

Be prepared for the thing to take forever to perk. If it finishes in less than half an hour, I’d be surprised.