imperial old fashioned units are impossible… as with the unit of time… and to make things worse… time differences can be a pain for parents when they try to call their children in far-flung continents…
it is also made even more confusing with Winter and Summer time differences… when day-light savings is turned on and off in the northern hemisphere. Winter-time (day-light savings) usually starts at the end of Oct for most countries and every country participating in this change, shifts time one hour backwards.
however, Summer-time begins at different times across the european countries which results in a week of extra 1 hour time differences for some cities when it happens during the last week of March until we arrive at the beginning of April. but when this happens, we return the ‘stolen’ hour back by moving time forwards by an hour…
here is a way i’ve come up this morning to calculated the current time (in 24hr format) at the country/city you are interested in:


STEP 1) </b
You need to know the Time Difference (in 24hr format) between the country you are in and the country/city of interest. It is more common to find this relative to Greenwich Mean Time (GMT) or Universal Central Time (UCT) and it depends on the Time-Zone of each country. A quick way to do this is to check on the time icon of your browser; right click and select ‘Adjust Date/Time‘ and a window pops up with the setting options. there is a tab for changing time-zones.
e.g. Singapore is +8 hours of GMT in Winter-time (+7 hrs GMT in Summer-time)
e.g. Minneapolis/St. Paul is -6 hours of GMT in Winter-time (** – 6 hrs GMT in Summer-time; and -7 hrs GMT for 1 week at the end of March)
so the Time Difference between Singapore and Minneapolis is 14 hours during Winter-time…
but NOTE : Singapore is + 14 hours of Minneapolis and Minneapolis is – 14 hours of Singapore. the underlined city will be referred to as the ‘city of interest’.
the + and – signs of the difference are important for the calculation
Step2)
Using this Time Difference with respect to the country/city of interest (including the sign of the difference), now check the Local Time at Present Country in 24hr format and apply the formula:
Current Time at CountryORCity of interest = Remainder when [Local Time at Present Country + Time Difference with respect to city of interest] is divided completely by 24
For Example:
Current Local Time in Minneapolis == 13hrs
Time Difference between Minneapolis and city of interest London == +6 hrs
Current time in London = MOD(13 + (+6) , 24) = remainder of ((13 + (+6)) / 24) = remainder of (19 / 24) = 19 hrs
Another Example:
Current Local Time in Singapore == 3hrs
Time Difference between Singapore and city of interest Munich == -7 hrs
Current time in Munich= MOD(3 + (-7) , 24) = remainder of (-4 / 24) = remainder of (24 – 4 / 24) = 20 hrs
Another Example:
Current Local Time in Minneapolis == 13hrs
Time Difference between Minneapolis and city of interest Adelaide == +16.5 hrs
Current time in Adelaide= MOD(13 + (+16.5) , 24) = remainder of (29.5 / 24) = 5.5 hrs
more succintly, the formula can be reduced to:
Current Time at CountryORCity of interest = MOD (Local Time at Present Country + Time Difference with respect to city of interest, 24)
MOD is a function or operator that gives a remainder for the division of a number (completely) by a divisor (in this case, 24). NOTE that e.g. MOD(4 , 24) = 4 and not 1/6.
in any case, the answer will give you the time of your city/country of interest in 24hr format.
here is an online website for more direct calculations which you can even personalize… but when you don’t have access to the www, the formula will come in handy… that is if you remember the time-zone differences!