Converting datetime.date to UTC timestamp in Python

If d = date(2011, 1, 1) is in UTC:

>>> from datetime import datetime, date >>> import calendar >>> timestamp1 = calendar.timegm(d.timetuple()) >>> datetime.utcfromtimestamp(timestamp1) datetime.datetime(2011, 1, 1, 0, 0) 

If d is in local timezone:

>>> import time >>> timestamp2 = time.mktime(d.timetuple()) # DO NOT USE IT WITH UTC DATE >>> datetime.fromtimestamp(timestamp2) datetime.datetime(2011, 1, 1, 0, 0) 

timestamp1 and timestamp2 may differ if midnight in the local timezone is not the same time instance as midnight in UTC.

mktime() may return a wrong result if d corresponds to an ambiguous local time (e.g., during DST transition) or if d is a past(future) date when the utc offset might have been different and the C mktime() has no access to the tz database on the given platform. You could use pytz module (e.g., via tzlocal.get_localzone()) to get access to the tz database on all platforms. Also, utcfromtimestamp() may fail and mktime() may return non-POSIX timestamp if "right" timezone is used.

To convert datetime.date object that represents date in UTC without calendar.timegm():

DAY = 24*60*60 # POSIX day in seconds (exact value) timestamp = (utc_date.toordinal() - date(1970, 1, 1).toordinal()) * DAY timestamp = (utc_date - date(1970, 1, 1)).days * DAY 

How can I get a date converted to seconds since epoch according to UTC?

To convert datetime.datetime (not datetime.date) object that already represents time in UTC to the corresponding POSIX timestamp (a float).

Python 3.3+

datetime.timestamp():

from datetime import timezone timestamp = dt.replace(tzinfo=timezone.utc).timestamp() 

Note: It is necessary to supply timezone.utc explicitly otherwise .timestamp() assume that your naive datetime object is in local timezone.

Python 3 (< 3.3)

From the docs for datetime.utcfromtimestamp():

There is no method to obtain the timestamp from a datetime instance, but POSIX timestamp corresponding to a datetime instance dt can be easily calculated as follows. For a naive dt:

timestamp = (dt - datetime(1970, 1, 1)) / timedelta(seconds=1) 

And for an aware dt:

timestamp = (dt - datetime(1970,1,1, tzinfo=timezone.utc)) / timedelta(seconds=1) 

Interesting read: Epoch time vs. time of day on the difference between What time is it? and How many seconds have elapsed?

See also: datetime needs an "epoch" method

Python 2

To adapt the above code for Python 2:

timestamp = (dt - datetime(1970, 1, 1)).total_seconds() 

where timedelta.total_seconds() is equivalent to (td.microseconds + (td.seconds + td.days * 24 * 3600) * 10**6) / 10**6 computed with true division enabled.

Example

from __future__ import division from datetime import datetime, timedelta def totimestamp(dt, epoch=datetime(1970,1,1)): td = dt - epoch # return td.total_seconds() return (td.microseconds + (td.seconds + td.days * 86400) * 10**6) / 10**6 now = datetime.utcnow() print now print totimestamp(now) 

Beware of floating-point issues.

Output

2012-01-08 15:34:10.022403 1326036850.02 

How to convert an aware datetime object to POSIX timestamp

assert dt.tzinfo is not None and dt.utcoffset() is not None timestamp = dt.timestamp() # Python 3.3+ 

On Python 3:

from datetime import datetime, timedelta, timezone epoch = datetime(1970, 1, 1, tzinfo=timezone.utc) timestamp = (dt - epoch) / timedelta(seconds=1) integer_timestamp = (dt - epoch) // timedelta(seconds=1) 

On Python 2:

# utc time = local time - utc offset utc_naive = dt.replace(tzinfo=None) - dt.utcoffset() timestamp = (utc_naive - datetime(1970, 1, 1)).total_seconds() 

For unix systems only:

>>> import datetime >>> d = datetime.date(2011, 1, 1) >>> d.strftime("%s") # <-- THIS IS THE CODE YOU WANT '1293832800' 

Note 1: dizzyf observed that this applies localized timezones. Don't use in production.

Note 2: Jakub Narębski noted that this ignores timezone information even for offset-aware datetime (tested for Python 2.7).

• Assumption 1: You're attempting to convert a date to a timestamp, however since a date covers a 24 hour period, there isn't a single timestamp that represents that date. I'll assume that you want to represent the timestamp of that date at midnight (00:00:00.000).

• Assumption 2: The date you present is not associated with a particular time zone, however you want to determine the offset from a particular time zone (UTC). Without knowing the time zone the date is in, it isn't possible to calculate a timestamp for a specific time zone. I'll assume that you want to treat the date as if it is in the local system time zone.

First, you can convert the date instance into a tuple representing the various time components using the timetuple() member:

dtt = d.timetuple() # time.struct_time(tm_year=2011, tm_mon=1, tm_mday=1, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=5, tm_yday=1, tm_isdst=-1) 

You can then convert that into a timestamp using time.mktime:

ts = time.mktime(dtt) # 1293868800.0 

You can verify this method by testing it with the epoch time itself (1970-01-01), in which case the function should return the timezone offset for the local time zone on that date:

d = datetime.date(1970,1,1) dtt = d.timetuple() # time.struct_time(tm_year=1970, tm_mon=1, tm_mday=1, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=3, tm_yday=1, tm_isdst=-1) ts = time.mktime(dtt) # 28800.0 

28800.0 is 8 hours, which would be correct for the Pacific time zone (where I'm at).

I defined my own two functions

• utc_time2datetime(utc_time, tz=None)
• datetime2utc_time(datetime)

here:

import time import datetime from pytz import timezone import calendar import pytz def utc_time2datetime(utc_time, tz=None): # convert utc time to utc datetime utc_datetime = datetime.datetime.fromtimestamp(utc_time) # add time zone to utc datetime if tz is None: tz_datetime = utc_datetime.astimezone(timezone('utc')) else: tz_datetime = utc_datetime.astimezone(tz) return tz_datetime def datetime2utc_time(datetime): # add utc time zone if no time zone is set if datetime.tzinfo is None: datetime = datetime.replace(tzinfo=timezone('utc')) # convert to utc time zone from whatever time zone the datetime is set to utc_datetime = datetime.astimezone(timezone('utc')).replace(tzinfo=None) # create a time tuple from datetime utc_timetuple = utc_datetime.timetuple() # create a time element from the tuple an add microseconds utc_time = calendar.timegm(utc_timetuple) + datetime.microsecond / 1E6 return utc_time 

A complete time-string contains:

• date
• time
• utcoffset [+HHMM or -HHMM]

For example:

1970-01-01 06:00:00 +0500 == 1970-01-01 01:00:00 +0000 == UNIX timestamp:3600

$ python3 >>> from datetime import datetime >>> from calendar import timegm >>> tm = '1970-01-01 06:00:00 +0500' >>> fmt = '%Y-%m-%d %H:%M:%S %z' >>> timegm(datetime.strptime(tm, fmt).utctimetuple()) 3600 

Note:

UNIX timestamp is a floating point number expressed in seconds since the epoch, in UTC.

Edit:

$ python3 >>> from datetime import datetime, timezone, timedelta >>> from calendar import timegm >>> dt = datetime(1970, 1, 1, 6, 0) >>> tz = timezone(timedelta(hours=5)) >>> timegm(dt.replace(tzinfo=tz).utctimetuple()) 3600 

follow the python2.7 document, you have to use calendar.timegm() instead of time.mktime()

>>> d = datetime.date(2011,01,01) >>> datetime.datetime.utcfromtimestamp(calendar.timegm(d.timetuple())) datetime.datetime(2011, 1, 1, 0, 0) 

Using the arrow package:

>>> import arrow >>> arrow.get(2010, 12, 31).timestamp 1293753600 >>> time.gmtime(1293753600) time.struct_time(tm_year=2010, tm_mon=12, tm_mday=31, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=4, tm_yday=365, tm_isdst=0) 

the question is a little confused. timestamps are not UTC - they're a Unix thing. the date might be UTC? assuming it is, and if you're using Python 3.2+, simple-date makes this trivial:

>>> SimpleDate(date(2011,1,1), tz='utc').timestamp 1293840000.0 

if you actually have the year, month and day you don't need to create the date:

>>> SimpleDate(2011,1,1, tz='utc').timestamp 1293840000.0 

and if the date is in some other timezone (this matters because we're assuming midnight without an associated time):

>>> SimpleDate(date(2011,1,1), tz='America/New_York').timestamp 1293858000.0 

[the idea behind simple-date is to collect all python's date and time stuff in one consistent class, so you can do any conversion. so, for example, it will also go the other way:

>>> SimpleDate(1293858000, tz='utc').date datetime.date(2011, 1, 1) 

]

This works for me, pass through a function.

from datetime import timezone, datetime, timedelta import datetime def utc_converter(dt): dt = datetime.datetime.now(timezone.utc) utc_time = dt.replace(tzinfo=timezone.utc) utc_timestamp = utc_time.timestamp() return utc_timestamp # create start and end timestamps _now = datetime.datetime.now() str_start = str(utc_converter(_now)) _end = _now + timedelta(seconds=10) str_end = str(utc_converter(_end)) 

i'm impressed of the deep discussion.

my 2 cents:

from datetime import datetime import time 

the timestamp in utc is:

timestamp = \ (datetime.utcnow() - datetime(1970,1,1)).total_seconds() 

or,

timestamp = time.time() 

if now results from datetime.now(), in the same DST

utcoffset = (datetime.now() - datetime.utcnow()).total_seconds() timestamp = \ (now - datetime(1970,1,1)).total_seconds() - utcoffset 

To convert a date into a UTC timestamp, it's best to specify explicitly the timezone before generating the timestamp:

from datetime import date, datetime, time, timezone def utc_date_to_timestamp(utc_date: date): dt = datetime.combine(utc_date, time(tzinfo=timezone.utc)) return dt.timestamp() 

Note that in the above snippet, if we were to omit the timezone specification, we would have a potential problem if the local timezone is different from GMT (which is aligned with UTC). Consider this example:

my_date = date(2021, 1, 1) wrong_timestamp = datetime.combine(my_date, time()).timestamp() print(datetime.utcfromtimestamp(wrong_timestamp)) # 2020-12-31 18:00:00 

Note that the specific value printed will differ depending on the local machine running the snippet.

I would suggest to use astimezone method of datetime because replace returns relative time.

from datetime import datetime, timezone datetime.astimezone(datetime.now(), tz=timezone.utc), datetime.now().replace(tzinfo=timezone.utc) 

this returns following dates. Here, my timezone is IST and I want to convert it to UTC. UTC is 5 hours 30 minutes behind of IST, so when I use replace, it adds 5 hours 30 minutes to current IST time.

(datetime.datetime(2025, 1, 8, 10, 5, 33, 539324, tzinfo=datetime.timezone.utc), datetime.datetime(2025, 1, 8, 15, 35, 33, 539324, tzinfo=datetime.timezone.utc)) 

which is not correct.

datetime.astimezone(datetime.now(), tz=timezone.utc), datetime.astimezone(datetime.now(), timezone.utc) 

But when I use, astimezone python finds equivalent of IST time in UTC.

(datetime.datetime(2025, 1, 8, 10, 6, 55, 237355, tzinfo=datetime.timezone.utc), datetime.datetime(2025, 1, 8, 10, 6, 55, 237355, tzinfo=datetime.timezone.utc))