How to Find the Time Difference Between Two Cities
Short answer
Subtract UTC offsets (including DST). New York (UTC−4 in summer) and London (UTC+1 in summer) differ by 5 hours: when it is 12:00 in London it is 07:00 in New York.
Flight apps and family chats ask “what’s the time difference?” The reliable method is offset arithmetic — or a converter that already did it.
Method
- Look up each city’s current UTC offset.
- Difference = offset_A − offset_B (in hours).
- Apply the difference to a clock time.
Examples
- London UTC+0 and New York UTC−5 → 5 hours (NY behind).
- London UTC+0 and India UTC+5:30 → 5.5 hours (India ahead).
- Los Angeles UTC−8 and Tokyo UTC+9 → 17 hours.
Confirm live offsets in the time zone converter. For three-plus cities, jump to the meeting planner.
Half-hour and 45-minute zones
India (+5:30), Nepal (+5:45) and parts of Australia break the “whole hour” habit. Always keep the minutes.
Open the free date difference calculator to check your result.
See also: how to convert time zones.
See also: how to plan meeting across time zones.
See also: how to count business days between dates.
More worked numbers
Change one input at a time so you build intuition. Write the formula, substitute values, then confirm with the free timezone converter. If the tool disagrees with your hand math, check units first (months vs years, percent vs decimal, inclusive ranges).
Common mistakes to avoid
- Mixing up percent and decimal forms (15% is 0.15, not 15).
- Using the wrong base when calculating a change or a reverse percentage.
- Ignoring fees, tax or daylight saving when the real-world total depends on them.
- Rounding too early in multi-step arithmetic.
How to practise
Invent three mini-problems from your own life — a bill, a grade, a trip, a loan quote — and solve them on paper before you open the calculator. Teaching the steps to someone else is one of the fastest ways to lock in the method.
Related tools on ViralScopeHub
After you finish this guide, explore the linked tools above and the related articles for neighbouring skills. Our calculators run privately in your browser with no sign-up, so you can check homework, budgets or work estimates without uploading data.
Quick reference card
Keep the short answer box at the top of this page as your cheat sheet. When a search result brought you here for a specific phrase, that box is designed to match the query with the formula first, then the examples below fill in the judgement calls.
Frequently asked questions
How do I calculate time difference between cities?
Compare their UTC offsets, including daylight saving, then subtract. Double-check units and confirm with the linked tool on this page before you rely on the figure for money or school decisions.
Is the difference the same all year?
Not if either place observes DST. Double-check units and confirm with the linked tool on this page before you rely on the figure for money or school decisions.
What is the time difference UK to US East Coast?
Usually 5 hours (UK ahead); 4 hours when only one side is on DST. Double-check units and confirm with the linked tool on this page before you rely on the figure for money or school decisions.
Can I get this without doing math?
Yes — use our time zone converter. Double-check units and confirm with the linked tool on this page before you rely on the figure for money or school decisions.