Index cards are one of the GM’s best friends — they’re useful, cheap and versatile.

Here are 7 12 ideas for making the most of index cards as a GM.

At least in the U.S., index cards generally come in two sizes — 4″ x 6″ and 3″ x 5″ — as well as in lined and unlined versions. I much prefer lined 3×5 cards to any other kind — 4x6s are just too big, and the lined side is too useful to give up.

To get the most out of some of these ideas, you’ll also need an index card box. These generally only cost a few bucks, and they hold several hundred cards. Most stores also sell little dividers for them, so you can alphabetize your cards. (I also like to put a thick rubber band around mine, since they have a tendency to pop open during travel.)

Update: In the comments, Lilith mentioned using an index card binder instead of a box, which will also work very well.

Here are some of the better uses I’ve found for index cards as a GM:

  • Counters: In emergencies, I cut up index cards to make counters. For D&D, I have several thousand Fiery Dragon counters, and I use pieces of index cards to size up Small creatures into Large ones.
  • Lists: I like to clip notes to the inside of my GM’s screen, and index cards tend to be just the right size; they’re also stiffer than paper, and last longer. List-wise, I always make a list of the party’s perception skills, and create other lists depending on the game.
  • Magic items: For D&D, I draw particularly interesting magic items on the blank side, and write their stats on the back. My players always seem to like these, even though the artwork isn’t stellar.
  • NPCs: Write the NPC’s name on the top of the lined side, and their description and relevant stats below. If you can draw reasonably well, sketch the NPC on the back of the card, or just paste on a printed-out picture. (This works very well with an index card box.)
  • World info: Every time you create a significant world element, write notes about it on an index card and file it in an alphabetized card box. When the PCs return to the Plucky Kobold — an inn you’ve long since forgotten about — you just flip to the Ps and there it is.

…and a couple more that I’ve heard about, but never tried myself:

  • Initiative cards: Give each PC their own card, and keep a few aside for NPCs and foes. In combat, write everyone’s initiative at the top of their card, put them in order, and then just cycle through the deck. You can also add frequently-referenced stats to each PC’s card — and use the tape trick to make the cards last longer.
  • Potions and other consumables: Many GMs like to give out index cards to represent common consumables — healing potions in D&D, for example. That way there’s no chance of losing track of them, and they can be passed between PCs with no bookkeeping.

Update: …and several reader tips, from the comments section below:

  • Items with charges: Magic items like wands and staves often have charges, so make a series of little checkboxes to represent each charge. Use the tape trick (mentioned above) to make them re-usable. (Frank)
  • Notes for players: Since you’ve already got a stack of index cards at the table, why not use them to write notes to your players? (DMN)
  • Random encounters: Write up a few for each region/terrain type, and draw from the deck as needed. (Dave)
  • Spell cards: Put all the info for a spell on each card, with checkboxes for duration if applicable. Then you can slide a paperclip along the duration track (or just check off the boxes) each round. (Frank)
  • Weapon cards: If you run a game with complicated weapon stats and options, putting all of the PCs’ weapons on an index card will be a big timesaver (and whatever weapon the player is holding is the one their PC has out). (Crazy Jerome)

Are you a fan of index cards? What are some of your favorite uses for them as a GM?