Most recipes call for one pound of coffee and two gallons of water. I bought the pound of coffee, but chose to halve the recipe for two separate batches. The brew will last for three weeks, which we'd surely drink up by then, but storing the stuff can be tricky if you don't own any gargantuan containers. It's your call.
Cold Brewed Iced Coffee adapted from The Pioneer Woman.
And, in case you are interested, Imbibe Magazine offers an informative read about the varying perpectives regarding hot and cold-brewed iced coffee with recipes included.