How do you read the number 1.5?



How should you read the number 1.5?

Should I read it as

  1. one and half


  1. one and a half

Any help would be appreciated.


Posted 2015-02-17T04:13:31.853

Reputation: 25 811

It is a guess without any context. – user3169 – 2015-02-17T04:24:14.260

10@user3169 one and half is never correct. – Catija – 2015-02-17T04:27:57.427

@Catija I was not referring to the listed options. As you said in your answer, there are several ways to say it, but which one to use depends on context. It would make for a better question. – user3169 – 2015-02-17T04:30:36.573

This needs to be edited to reflect the new information provided in the conversation under my answer... I can not do this because there is already a pending edit. – Catija – 2015-02-17T05:06:54.453



You have several options:

  • one point five
  • one and a half
  • one and one-half - can seem wordy.
  • one and five-tenths - mathematically correct term, not used regularly.

These are all correct.

The hyphens in the last two are optional to some degree depending on the source. Including it is arguably more correct.

one and half is not correct... usually. Based on your comments, it looks like you're seeing it used in technical, electrical system uses:

One and half breaker Bus System Chart

In this case, it may be correct but I don't see any evidence that they would ever write it out as 1.5.


Posted 2015-02-17T04:13:31.853

Reputation: 25 211

But, *one and half of one* works. It just sounds, really, *really* awkward. – Pyraminx – 2015-02-17T04:37:58.430

(1) One and A Half Breaker Bus System, (2) One and Half Breaker: Then the former is right, the latter wrong, aren't they? – Listenever – 2015-02-17T04:51:57.163

1@Listenever In that sort of use, it seems that either is accepted but (as someone who knows nothing about electrical systems), it doesn't look like that they would write it as 1.5. – Catija – 2015-02-17T04:58:00.937

3IMHO, "one and half of one" is so awkward that it does not "work". – Brian Hitchcock – 2015-02-17T06:48:28.667

6Just to add: "one point five" would be standard if reading the number as written. One and a half tends to be used descriptively, rather than when reading a decimal aloud. – Jon Story – 2015-02-17T09:58:35.277

‘One and one-half’ sounds pretty awkward to my (British English) ears. – Robin Whittleton – 2015-02-17T13:16:59.907

Is the hyphen in "one-half" really correct? I can think of some situations where I would tie the whole thing together as "one-and-{one,a}-half", but otherwise I'd leave them all separate. – Random832 – 2015-02-17T13:57:31.303

@Random832 The hyphen is optional but it is correct.

– Catija – 2015-02-17T14:38:40.267

1@Robin It sounds awkward to a lot of AmE people, too. It's the correct mathematical phrasing but is generally simplified to a half, which is why I listed it last. – Catija – 2015-02-17T14:40:25.423

Another possibility, that I've seen particularly in children's maths books, is "one-decimal-five". I think perhaps airline pilots and the like might use "decimal" instead of "point" – Gremlin – 2015-02-17T17:46:40.540

@Eoin This isn't something I'm familiar with. – Catija – 2015-02-17T17:51:32.333

Note also that everywhere else on the linked Electrical System page, they talk about the "One And A Half Breaker System"; the only place where "One & Half" appears is in the diagram shown. – Hellion – 2015-02-17T18:20:56.780


"1.5" would be read as "one point five". Note that "1.50" is "one point five oh" or "one point five zero", not "one point fifty", since fifty means five times ten.

David Richerby

Posted 2015-02-17T04:13:31.853

Reputation: 7 931