PHP strtotime: Get previous month

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How to get previous month and year relative to today, using strtotime and date?

Today is December, 31st but strtotime("-1 months") returns December:

echo date("Y-m", strtotime("-1 months"));

Same for strtotime("last month")

How can I properly return the previous month (November)?

Test: http://codepad.viper-7.com/XvMaMB

score 38 · Accepted Answer · answered Dec 31 '12 at 14:17

38

strtotime("first day of last month")

The first day of is the important part as detailed on the Relative Formats manual page.

Example: http://codepad.viper-7.com/dB35q8 (with hard-coded today's date)

answered Dec 31 '12 at 14:17

salathe

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Thanks. Very misleading! Sounds like it would return "1" or the weekday. – Martin Dec 31 '12 at 14:19
@Martin Try it and find out – Daryl Gill Dec 31 '12 at 14:19
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@Martin: `strtotime` always returns a timestamp (or false on failure). So it *will* return a timestamp of the first day of the last month, but since you are outputting it in `Y-m` format, that's fine for you. – Travesty3 Dec 31 '12 at 14:21
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"first day of next month" doesn't work in PHP 5.2.4 – Martin Dec 31 '12 at 14:29
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Lots of things won't work in ancient versions of the language. – salathe Dec 31 '12 at 20:02
What will happen if the date is something like 2014-01-31 will it return 2013-12-01..? – Rahat Islam Khan May 03 '14 at 06:49

score 11 · Answer 2 · answered Dec 31 '12 at 14:26

11

strtotime("-1 months") would be 2012-11-31, but there's no November, 31st. It is one day past 2012-11-30, which gives 2012-12-01. You will see it, when you do

echo date("Y-m-d", strtotime("-1 months"));

gives as output

2012-12-01

See codepad

answered Dec 31 '12 at 14:26

Olaf Dietsche

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Thanks, that explains it. – Martin Dec 31 '12 at 14:32

PHP strtotime: Get previous month

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