Why Hijri Dates Differ Between Countries

The crescent does not rise everywhere at once

Every Hijri month begins with the sighting of the new crescent moon. That sounds simple, but the moon is not equally visible everywhere on the same evening. On the 29th evening of a month, the crescent might be old enough and high enough to see in Saudi Arabia, yet still too thin or too low on the horizon in Pakistan or Indonesia.

Geography decides this. The moon's age at sunset, its height above the horizon, the angle between the sun and the moon, even haze and city lights all play a part. A crescent clearly visible over Riyadh can be genuinely invisible over Jakarta on the same night. So one country declares the new month and another completes 30 days. Both followed the same rule. The sky just gave them different answers.

I have watched this play out every year in Pakistan. On the 29th evening, the Ruet-e-Hilal Committee meets in Karachi while zonal committees gather in Lahore, Peshawar, and Quetta, collecting testimony from witnesses across the country. Sometimes the announcement comes quickly: moon sighted, Ramadan begins tomorrow. Other years the chairman appears on television late at night to say no credible testimony was received, and the month completes 30 days. It feels dramatic, but it is simply the system working. Nobody in that room is checking what Saudi Arabia did. They are checking the sky over Pakistan.

Two ways countries decide: local sighting or following Saudi Arabia

Here is where human choice enters. Some countries insist on their own local sighting. Pakistan's Ruet-e-Hilal Committee, Morocco's moon-sighting network, and Oman's committee only accept testimony from within their own borders. The month starts when their own people see the moon.

Other countries follow Saudi Arabia's announcement instead. There is a practical reason: Hajj happens in Mecca, and its dates come from Saudi's declaration, so many governments prefer one shared calendar for the whole ummah. The result is a patchwork. Country A waits for its own crescent. Country B starts when Riyadh announces. A one-day gap between them is almost guaranteed at least once a year.

So which approach is right? Honestly, both have serious scholarship behind them, and this debate is over a thousand years old. I check my own country's moon-sighting announcement before finalizing Eid plans, and that is what I recommend to you: follow where you live.

The second source of differences: the calendar math

There is another layer, and it lives inside your phone. Islamic calendar apps and printed calendars cannot wait for the moon, so they calculate. But they do not all calculate the same way.

The tabular calendar uses a fixed 30-year arithmetic cycle with 11 leap years. It is neat, predictable, and completely blind to the actual sky. Umm al-Qura, Saudi Arabia's official calendar, is pre-computed from predicted moon visibility over Mecca, which tracks the real moon more closely but still guesses. Real sighting committees go outside and look. Three methods, three possible answers, and any two of them can land a day apart.

This is why two apps on the same phone can disagree about today's Hijri date. Neither is broken. They are just answering different questions: what the formula says versus what the sky said.

One Ramadan, three different start days: an illustration

Put it all together and you can see how a single Ramadan رمضان gets three different start days. The table below is illustrative, not a record of any specific year, but the mechanism behind it plays out nearly every year.

Approach	How the month is declared	Typical result
Local sighting committee	Crescent seen on the 29th evening inside the country	Starts Day X
Following Saudi Arabia	Riyadh announces the crescent over Mecca	Starts Day X or Day X+1
Tabular calendar app	Pre-computed 30-year cycle, no sky involved	Starts Day X or Day X+1

Notice that none of these rows did anything wrong. They applied their rule correctly and got different answers, because the rules themselves differ and the crescent genuinely appears on different evenings in different places.

What you should actually do

Keep it simple. For fasting, Eid, and any act of worship, follow the official announcement of the country you are in. That is the mainstream position across schools of thought, and it keeps the whole community starting and ending together, which is the entire point.

This gets slightly tricky for expat families. If you live in London but your parents are in Lahore, whose Eid do you celebrate? Yours, where you live. Pray Eid with your local mosque on the day your local community declares it. Calling home to compare dates is a beloved Ramadan tradition in my family too, but it should never override the announcement of the place you are standing in. And if you live somewhere with no official moon-sighting body at all, follow the nearest reputable mosque or Islamic council and stay consistent with them year to year.

Use calculated calendars for planning only. If you want to know roughly when Ramadan 1448 falls so you can book time off, check our Ramadan countdown or the 1448 Hijri calendar. If you want to convert a specific Gregorian date, use the Hijri date converter. And if you are curious how this site computes its dates, the methodology page lays it all out. But when the 29th of Sha'ban شعبان arrives, close the apps and wait for the announcement. The moon has the final word.