Always have exact (UK) change

I never thought about this, but there is a way of going out of the house with a small number of coins, and always (at least, the first time) having the right amount of change between 1p and 99p with just 8 coins.

In fact, if you add a few extra coins, you can have the right change from 1p all the way up to £6.10.

The magic combination is:

  • One penny
  • 2 two pence
  • 1 five pence
  • 1 ten pence
  • 2 twenty pence
  • 1 fifty pence

Then optionally you can add:

  • 1 pound coin
  • 2 two pound coins

To work this out, use a greedy strategy; keep picking the biggest coin less than or equal to the remaining amount. You can keep doing that up through notes as well if you want.

Obviously this only works the first time you need exact change, but it seems like a great way of getting rid of your change. I find I can take a handful of change with me and still have to go “sorry, I don’t have the right amount” and end up with even more change.

Note I didn’t work this out myself. I saw the idea on Lifehacker and others have discussed the problem.

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