Should I always put 0x at the start of Ethereum addresses? Sending ether to addresses without 0x seem to work perfectly fine.

when sending to an address, do you include the "0x" before the rest of the number?

The address in my coinbase starts with 0x, then the rest of the receiving address. However my wallet file i created with geth doesn't have the 0x in the name.


  • 2
    This question feels a bit engineered, to improve its quality can you give some more context in the question itself in what context this question occurs? – Joris Bontje Jan 24 '16 at 21:23
  • But is it a zero or letter O ? – Chipper Fawkes Mar 3 '18 at 19:56
  • @ChipperFawkes It's a zero. – eth Mar 4 '18 at 20:22
  • Does it start with 0x or Ox? I am dyslexic. Is it zero x or the letter Ox? – Joseph Cassidy Mar 5 at 3:54
  • @JosephCassidy It is zero x. – eth Apr 20 at 6:53

Yes but the 0x should already be there. You should not be typing addresses in manually because they currently do not have checksums and mistakes can be costly: more details here specifically be "careful to always include the "0x" on the front of the raw ones (which you should be doing anyways)".

When transferring any large amounts, don't forget to test with a small amount first. Similarly, if you are copying+pasting and the 0x isn't already there (maybe some blockchain explorers don't have the 0x), be careful if you add the "0x".

With Ethereum ICAP addresses, the 0x should not be added.


I feel like @eth did not answer the question.

The 0x is necessary, because it lets the receiver know it's an address in hexadecimal format.

  • 1
    Upvoted, yes 0x makes it clear that the address is hex. – eth Jun 23 '17 at 6:19

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