City comparison · time difference and converter
Phnom Penh is 6 hours ahead of London right now. London sits in United Kingdom on London; Phnom Penh sits in Cambodia on Phnom Penh. They are roughly 10,016 km apart (6,224 mi), a flight of about 12h 47m. London's metro holds around 9.5 million people; Phnom Penh's around 1.6 million.
Slot 1
09:00 / 15:00
London / Phnom Penh
Both inside business hoursSlot 2
10:00 / 16:00
London / Phnom Penh
Both inside business hoursSlot 3
03:00 / 09:00
London / Phnom Penh
Partial overlapEach row is one hour in London. Green rows are inside business hours in both cities; amber means only one side is at their desk; grey rows fall outside business hours in both.
No public holidays in United Kingdom or Cambodia this month.
Great-circle distance
10,016 km
(6,224 mi)
Approximate flight
12h 47m
850 km/h cruise + 1h taxi/climb/descent
Jet lag
6h
Roughly 1 day to adjust per timezone crossed
The heatmap gives you the shape of the day. If you need to convert one specific hour — say a customer call or a release window — open the converter with both cities already loaded.
Open in converter →The difference between London and Phnom Penh is not really a number, it's a daily rhythm. Phnom Penh is 6 hours ahead of London on the clock today, but the lived version is that Phnom Penh is wrapping up the working day while London is still in the morning, and the overlap people actually use is narrow. That gap, more than the raw offset, is what teams have to design around.
In London, the working day picks up earliest in the financial districts — City of London desks switch on by 07:30 for the European open. The mood in Phnom Penh is its own story: Phnom Penh settles into the evening at the usual hour, with the local commuter pattern setting the pace. If you are scheduling between the two, the heatmap above marks the rows where both patterns line up.
Daylight saving is the other thing to keep an eye on. United Kingdom shifts the clock on the last Sunday of March and October; Cambodia either follows its region's DST pattern or stays put all year. When the two changes are weeks apart, the offset between London and Phnom Penh is one hour off the usual for that stretch — a cliff that catches recurring calendar invites unless your calendar app rebases them automatically. Pin the meeting to a city, not an offset, and the tool handles the rest.
For travellers, the 12h 47m flight is the short version of the story. The longer one is jet lag: roughly one day of adjustment per timezone crossed, which means a trip across the 6-hour gap costs about 6 groggy days on each side. Pilots and cabin crew swear by morning sunlight and an early walk; whatever your routine, the wall-clock numbers above are the source of truth for your first morning in the new city.