Time differences between major cities

These are the 66 city pairs with the most search suggestions for “time difference between …”. Of them, 56 have a gap that changes during the year, 18 pass through three different gaps because the two cities change clocks on different weekends, and 16 have no office hour in common at all on a 9-to-5 day.

• New York and LondonLondon ahead by 5 hours · 3 hours of shared office time
• New York and SydneySydney ahead by 14–16 hours · no shared office hours
• New York and ParisParis ahead by 6 hours · 2 hours of shared office time
• London and Los AngelesLos Angeles behind by 8 hours · no shared office hours
• London and SydneySydney ahead by 9–11 hours · no shared office hours
• London and DubaiDubai ahead by 3–4 hours · 5 hours of shared office time
• London and BrisbaneBrisbane ahead by 9–10 hours · no shared office hours
• Sydney and SingaporeSingapore behind by 2–3 hours · 6 hours of shared office time
• New York and Los AngelesLos Angeles behind by 3 hours · 5 hours of shared office time
• New York and ChicagoChicago behind by 1 hour · 7 hours of shared office time
• New York and TokyoTokyo ahead by 13–14 hours · no shared office hours
• London and SingaporeSingapore ahead by 7–8 hours · 1 hour of shared office time
• London and VancouverVancouver behind by 8 hours · no shared office hours
• Sydney and BrisbaneBrisbane behind by 0–1 hours · 8 hours of shared office time
• London and ChicagoChicago behind by 6 hours · 2 hours of shared office time
• Toronto and VancouverVancouver behind by 3 hours · 5 hours of shared office time
• Singapore and SeoulSeoul ahead by 1 hour · 7 hours of shared office time
• London and AmsterdamAmsterdam ahead by 1 hour · 7 hours of shared office time
• Los Angeles and SydneySydney ahead by 17–19 hours · 3 hours of shared office time
• Sydney and MelbourneSame clock time · 8 hours of shared office time
• New York and DubaiDubai ahead by 8–9 hours · no shared office hours
• London and TokyoTokyo ahead by 8–9 hours · no shared office hours
• London and CalgaryCalgary behind by 7 hours · 1 hour of shared office time
• London and DublinSame clock time · 8 hours of shared office time
• Los Angeles and TokyoTokyo ahead by 16–17 hours · 1 hour of shared office time
• Singapore and Hong KongSame clock time · 8 hours of shared office time
• New York and TorontoSame clock time · 8 hours of shared office time
• New York and PhoenixPhoenix behind by 2–3 hours · 6 hours of shared office time
• London and AdelaideAdelaide ahead by 8½–10½ hours · no shared office hours
• Los Angeles and ParisParis ahead by 9 hours · no shared office hours
• Sydney and VancouverVancouver behind by 17–19 hours · 3 hours of shared office time
• Sydney and AdelaideAdelaide behind by 30 minutes · 7 hours 30 minutes of shared office time
• London and CairoCairo ahead by 2 hours · 6 hours of shared office time
• Sydney and AucklandAuckland ahead by 2 hours · 6 hours of shared office time
• New York and SingaporeSingapore ahead by 12–13 hours · no shared office hours
• London and IstanbulIstanbul ahead by 2–3 hours · 6 hours of shared office time
• London and BangkokBangkok ahead by 6–7 hours · 2 hours of shared office time
• Los Angeles and ChicagoChicago ahead by 2 hours · 6 hours of shared office time
• Los Angeles and PhoenixPhoenix ahead by 0–1 hours · 8 hours of shared office time
• Chicago and PhoenixPhoenix behind by 1–2 hours · 7 hours of shared office time
• Toronto and CalgaryCalgary behind by 2 hours · 6 hours of shared office time
• Sydney and DubaiDubai behind by 6–7 hours · 2 hours of shared office time
• Sydney and TokyoTokyo behind by 1–2 hours · 7 hours of shared office time
• Singapore and BangkokBangkok behind by 1 hour · 7 hours of shared office time
• London and PhoenixPhoenix behind by 7–8 hours · 1 hour of shared office time
• London and AucklandAuckland ahead by 11–13 hours · no shared office hours
• London and DelhiDelhi ahead by 4½–5½ hours · 3 hours 30 minutes of shared office time
• Sydney and ParisParis behind by 8–10 hours · no shared office hours
• Tokyo and VancouverVancouver behind by 16–17 hours · 1 hour of shared office time
• Tokyo and SeoulSame clock time · 8 hours of shared office time
• New York and Mexico CityMexico City behind by 1–2 hours · 7 hours of shared office time
• London and DenverDenver behind by 7 hours · 1 hour of shared office time
• London and Mexico CityMexico City behind by 6–7 hours · 2 hours of shared office time
• Los Angeles and SingaporeSingapore ahead by 15–16 hours · no shared office hours
• Los Angeles and AucklandAuckland ahead by 19–21 hours · 5 hours of shared office time
• Dubai and DohaDoha behind by 1 hour · 7 hours of shared office time
• Dubai and DelhiDelhi ahead by 1 hour 30 minutes · 6 hours 30 minutes of shared office time
• New York and MumbaiMumbai ahead by 9½–10½ hours · no shared office hours
• London and LagosLagos ahead by 0–1 hours · 8 hours of shared office time
• Los Angeles and DenverDenver ahead by 1 hour · 7 hours of shared office time
• Los Angeles and VancouverSame clock time · 8 hours of shared office time
• Los Angeles and BrisbaneBrisbane ahead by 17–18 hours · 2 hours of shared office time
• Los Angeles and Mexico CityMexico City ahead by 1–2 hours · 7 hours of shared office time
• Chicago and SydneySydney ahead by 15–17 hours · 1 hour of shared office time
• Chicago and TokyoTokyo ahead by 14–15 hours · no shared office hours
• Chicago and ParisParis ahead by 7 hours · 1 hour of shared office time

City time zones

• New YorkUTC−5 / UTC−4 · changes clocks
• LondonUTC / UTC+1 · changes clocks
• Los AngelesUTC−8 / UTC−7 · changes clocks
• ChicagoUTC−6 / UTC−5 · changes clocks
• SydneyUTC+11 / UTC+10 · changes clocks
• DubaiUTC+4 · no clock changes
• SingaporeUTC+8 · no clock changes
• TokyoUTC+9 · no clock changes
• ParisUTC+1 / UTC+2 · changes clocks
• MumbaiUTC+5:30 · no clock changes
• PhoenixUTC−7 · no clock changes
• DenverUTC−7 / UTC−6 · changes clocks
• VancouverUTC−8 / UTC−7 · changes clocks
• BrisbaneUTC+10 · no clock changes
• AucklandUTC+13 / UTC+12 · changes clocks
• IstanbulUTC+3 · no clock changes
• CairoUTC+2 / UTC+3 · changes clocks
• LagosUTC+1 · no clock changes
• BangkokUTC+7 · no clock changes
• Mexico CityUTC−6 · no clock changes
• AdelaideUTC+10:30 / UTC+9:30 · changes clocks
• CalgaryUTC−7 / UTC−6 · changes clocks

How these pairs were chosen

We asked Google's search suggestions for “time difference between A and B” in both orders for 1005 pairs of 76 large cities (measured 2026-10-10, US English) and kept the pairs where at least 10 suggestions name both cities. When two pairs follow exactly the same clocks all year — New York–London and Toronto–London, for example — only the more searched one gets a page, because the numbers on both would be identical. Any other combination works in the planner.

How to read a pair page

Every pair page opens with the answer in one line, followed by a planner already loaded with the two cities. Below it, four figures summarise the pair: the gap, each city’s offset from UTC in January and in July, and the number of hours that a 9-to-5 day in one city shares with a 9-to-5 day in the other. January and July are used because they sit near the middle of northern winter and summer, so together they show the largest swing the pair makes in a year.

A gap written as a single number, such as seven hours, means both cities keep the same offset relation all year. A range, such as 15–17 hours, means at least one city changes its clocks, and the page then lists the weekends on which the gap steps from one value to the next. When the pair passes through three values, the two cities change on different dates; that is the case worth checking before scheduling anything in March, late October or early November.

Why some pairs share no office hours

A 9-to-5 day covers eight hours of the 24, so two cities can share at most eight. Each hour of gap beyond zero removes one hour of overlap until the gap reaches eight, at which point the days only touch at the edges. Past eight hours the overlap is zero, and past sixteen it returns, because the far side of the world is a day away rather than a half-day away. That is why Chicago and Sydney have a small shared window while Chicago and Tokyo have none.

Pairs without any common office hour are not unusable. They need a decision about who stretches: an early start in one city, an evening call in the other, or an asynchronous routine in which written updates cross the gap and live calls are rare. The pair pages show which hours of each office day fall in the other city’s night, so you can see how much of the stretch you are asking for.

What the list does not cover

The pairs are the combinations people search for most, not every possible combination, and cities that follow the same clocks as a listed city are folded into that city’s page. If you do not find your pair, open the planner and add the two cities; it uses the same calculation as the pages above and works for any listed city. The planner is also the right tool when you need a date other than the two reference weeks.

City names, coordinates and time zone assignments: GeoNames, licensed under CC BY 4.0 (selection and renaming of some cities by this site). Clock times are computed in your browser from the IANA time zone database. Sources and limits.