If you're anything like me-hell, if you've got anything less than a Ph.D. in combinatorics-you probably have a hard time figuring out how in God's name to put a sum on your MetroCard that doesn't result in your ending up with a wallet full of cards that have 65 cents each on them. Wonder no more! Via the estimable Katie Bakes, please enjoy the MetroCard bonus calculator. And if you see something, say something.
Related: This New Yorker cartoon, which will only be funny to those of you who remember that MetroCards used to be blue.

Am I weird for just adding money onto the same card over and over? If it gets really old I just use the last amount on the bus and pay the difference in change.
I used the same metrocard for so long it finally expired on me and I had to transfer the balance to a new card. It's fun to initiate an entirely new process on a vending machine!
sounds hot.
I avoid this entirely by purchasing unlimited. Living in Brooklyn, working in Manhattan, and rarely sleeping make it a worthwhile investment.
I know. Non-unlimiteds are for tourists, people who walk to work, and the Riches.
Damn, there goes an interview question I sometimes ask people!
I would totally hire somebody who knew about metrocardbonuscalculator.com.
It would at least cancel the automatic fail I assign to someone who asks me for Facebook address (or whatever one has on Facebook)
New York is Alright if You Like Saxophones
I just go up to the station booth and they combine the leftovers all onto one MetroCard. Pretty easy...
Still, a pretty awesome tool, that is.