# Maximum utility from the smallest number of bills **URL:** \ **Category:** In My Humble Opinion\ **Created:** [September 2, 2026, 11:41pm UTC](https://boards.straightdope.com/t/maximum-utility-from-the-smallest-number-of-bills/1032782 "2026-09-02T23:41:16Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![steronz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/steronz/32/11765_2.png) [@steronz](https://boards.straightdope.com/u/steronz)\ **Post date:** [September 2, 2026, 11:41pm UTC](https://boards.straightdope.com/t/maximum-utility-from-the-smallest-number-of-bills/1032782/1 "2026-09-02T23:41:16Z")
I’m downsizing my wallet again, but I’m not ready to completely stop carrying cash. Why? No idea. Only thing I use cash for is non-restaurant tips and lemonade stands. What’s the most utility you can get from the smallest number of bills? ---
**Author:** ![steronz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/steronz/32/11765_2.png) [@steronz](https://boards.straightdope.com/u/steronz)\ **Post date:** [September 2, 2026, 11:42pm UTC](https://boards.straightdope.com/t/maximum-utility-from-the-smallest-number-of-bills/1032782/2 "2026-09-02T23:42:48Z")
I can make a case for $47 (20x2, 5x1, 1x2) or $26 (20, 5, 1). But I’m not sure I have any justification for either. ---
**Author:** ![hajario](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hajario/32/171_2.png) [@hajario](https://boards.straightdope.com/u/hajario)\ **Post date:** [September 3, 2026, 12:11am UTC](https://boards.straightdope.com/t/maximum-utility-from-the-smallest-number-of-bills/1032782/3 "2026-09-03T00:11:05Z")
Are you assuming that the recipient can’t make change and you don’t want to overpay? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 4, 2026, 1:47am UTC](https://boards.straightdope.com/t/maximum-utility-from-the-smallest-number-of-bills/1032782/4 "2026-09-04T01:47:45Z")
Similar for me, except it’s usually bake sales at school. I generally assume they can make change for a fiver, but a twenty is iffy. ---
**Author:** ![PastTense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pasttense/32/14550_2.png) [@PastTense](https://boards.straightdope.com/u/PastTense)\ **Post date:** [September 4, 2026, 2:31am UTC](https://boards.straightdope.com/t/maximum-utility-from-the-smallest-number-of-bills/1032782/5 "2026-09-04T02:31:07Z")
I would carry enough cash to fill up your gas tank [this is the only gas station around and the card processing system is down]. ---
**Author:** ![steronz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/steronz/32/11765_2.png) [@steronz](https://boards.straightdope.com/u/steronz)\ **Post date:** [September 4, 2026, 3:21am UTC](https://boards.straightdope.com/t/maximum-utility-from-the-smallest-number-of-bills/1032782/6 "2026-09-04T03:21:27Z")
In this economy?! ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [September 4, 2026, 1:51pm UTC](https://boards.straightdope.com/t/maximum-utility-from-the-smallest-number-of-bills/1032782/7 "2026-09-04T13:51:36Z")
> [@PastTense](#): > > I would carry enough cash to fill up your gas tank [this is the only gas station around and the card processing system is down]. Agreed. I keep a folded $100 hidden in my wallet. There have been a couple times when I had to hire a tow truck and they didn’t take cards, and some times when I needed gas and the gas station couldn’t take cards. That emergency $100 came in handy in those situations. As far as bills, my method has been to have 2 wallets. In my wallet I carry on me in my pocket I have the emergency $100 bill and I also have several $20s and $50s. If I need to buy anything they can usually break a $20. But in my car I keep a second wallet that only has cash in it. That one is full of smaller bills $1s, $5s and $10s (I also have a large coin collection in my car of quarters, dimes, nickels, pennies). That way if I’m ever in a situation where I need smaller bills or loose change I have them in the car, but I don’t need to carry them in my wallet that I have on me. Anyway, thats kind of off topic. I guess if you want the most utility I would keep a $20, $10, a $5 and 2-3 $1 bills. That’s about 5-6 paper bills but that will give you a lot of flexibility. ---
**Author:** ![ASL\_v2.0](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/asl_v2.0/32/3525_2.png) [@ASL\_v2.0](https://boards.straightdope.com/u/ASL_v2.0)\ **Post date:** [September 4, 2026, 3:06pm UTC](https://boards.straightdope.com/t/maximum-utility-from-the-smallest-number-of-bills/1032782/8 "2026-09-04T15:06:41Z")
> [@hajario](#): > > Are you assuming that the recipient can’t make change and you don’t want to overpay? Same question for me. Because otherwise the answer seems pretty straightforward: it’s 20s all the way down. ---
**Author:** ![steronz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/steronz/32/11765_2.png) [@steronz](https://boards.straightdope.com/u/steronz)\ **Post date:** [September 4, 2026, 3:40pm UTC](https://boards.straightdope.com/t/maximum-utility-from-the-smallest-number-of-bills/1032782/9 "2026-09-04T15:40:43Z")
It’s a good question, and I think the answer is “I don’t mind overpaying or overtipping as long as it’s jot awkward.” Since this is an emergency fund, if I tip a 20 on a $15 meal it’s not the end of the world. ---
**Author:** ![ASL\_v2.0](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/asl_v2.0/32/3525_2.png) [@ASL\_v2.0](https://boards.straightdope.com/u/ASL_v2.0)\ **Post date:** [September 4, 2026, 4:27pm UTC](https://boards.straightdope.com/t/maximum-utility-from-the-smallest-number-of-bills/1032782/10 "2026-09-04T16:27:47Z")
Maybe a range would be helpful? How much cash do you use in a “splurge” week, a typical week, and a “lean” week? ---
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [September 4, 2026, 6:25pm UTC](https://boards.straightdope.com/t/maximum-utility-from-the-smallest-number-of-bills/1032782/11 "2026-09-04T18:25:19Z")
I guess I’m not understanding what is meant by “utility” in this question. If the question means “which set of N bills allows you the maximum purchasing power?”, the answer is obviously N $100 bills. If the question has a different meaning, it’s not clear to me what it is. ---
**Author:** ![steronz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/steronz/32/11765_2.png) [@steronz](https://boards.straightdope.com/u/steronz)\ **Post date:** [September 4, 2026, 6:38pm UTC](https://boards.straightdope.com/t/maximum-utility-from-the-smallest-number-of-bills/1032782/12 "2026-09-04T18:38:02Z")
Right, I wasn’t expecting this much confusion. But I basically don’t use cash at all anymore. I still carry it, and sometimes it gets spent, but not regularly enough for any patterns to emerge. I don’t feel comfortable not having _any_ cash on me, but I don’t have the foggiest idea of what I might need it for next. So I’m crowdsourcing the problem – what feels _generally_ useful in a largely post-cash society without feeling like I’m a wallet prepper. ---
**Author:** ![hajario](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hajario/32/171_2.png) [@hajario](https://boards.straightdope.com/u/hajario)\ **Post date:** [September 4, 2026, 8:19pm UTC](https://boards.straightdope.com/t/maximum-utility-from-the-smallest-number-of-bills/1032782/13 "2026-09-04T20:19:35Z")
Ok. Three twenties, three fives, five ones. ---
**Author:** ![Thumper668](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thumper668/32/20803_2.png) [@Thumper668](https://boards.straightdope.com/u/Thumper668)\ **Post date:** [September 4, 2026, 8:27pm UTC](https://boards.straightdope.com/t/maximum-utility-from-the-smallest-number-of-bills/1032782/14 "2026-09-04T20:27:24Z")
I keep 3 20s in my wallet primarily in case I need to fill the gas tank and the cash price is cheaper than the card price (which is common in NJ). Sometimes I use about $10 of it if I need to make a run to the dump with a couple weeks of garbage. ---
**Author:** ![ASL\_v2.0](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/asl_v2.0/32/3525_2.png) [@ASL\_v2.0](https://boards.straightdope.com/u/ASL_v2.0)\ **Post date:** [September 4, 2026, 9:13pm UTC](https://boards.straightdope.com/t/maximum-utility-from-the-smallest-number-of-bills/1032782/15 "2026-09-04T21:13:11Z")
> [@hajario](#): > > Ok. Three twenties, three fives, five ones. Yes, I agree. This is the mathematically correct answer. If you want to add some whimsy to someone’s day, replace a couple of the ones with a $2 bill. If you feel it’s too much money, then deduct a twenty (or two twenties). Scales beautifully. ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [September 4, 2026, 9:24pm UTC](https://boards.straightdope.com/t/maximum-utility-from-the-smallest-number-of-bills/1032782/16 "2026-09-04T21:24:10Z")
The OP only mentioned non-restaurant tips and lemonade stands. So wouldn’t several five-dollar bills be sufficient? That is assuming you’re giving five bucks as a tip.