Drawing all four aces as your first four cards

1 in 270,725

There is exactly one way to draw all four aces, out of 270,725 possible combinations of four cards from a standard deck.

Being dealt a royal flush in five-card poker

1 in 649,740

Four possible royal flushes (one per suit), out of nearly 2.6 million five-card hands.

Being dealt any flush in five-card poker

1 in 508

Flushes are rare enough to celebrate, common enough to actually happen in a long session.

Rolling the same number six times in a row

1 in 7,776

The first roll doesn't need to match anything. After that, each roll has a 1 in 6 chance of repeating.

Flipping heads ten times in a row

1 in 1,024

Each flip is independent. The probability halves with every additional flip required.

Flips in a row: 10

Being struck by lightning in your lifetime (UK)

1 in 300,000

Rare, but not as rare as most people assume. Around 30–60 people are struck by lightning in the UK each year.

Source: UK Met Office estimates. US figure is approximately 1 in 15,300 over 80 years.

Being involved in a fatal plane crash as a passenger

1 in 11,000,000 per flight

Flying is extraordinarily safe. You'd need to fly every day for 30,000 years to make a fatal crash statistically likely.

Source: Aviation safety data — approximately 1 fatal accident per 16 million flights.

Dying in a car accident in your lifetime (UK)

1 in 240

The mundane risks are the real ones. This is why seatbelts matter far more than shark repellent.

Source: UK road fatality statistics, lifetime risk estimate.

Being attacked by a shark in your lifetime

1 in 3,748,067

You are roughly 15,000 times more likely to be killed in a road accident than by a shark.

Source: Florida Museum of Natural History.

Finding a four-leaf clover on your first try

1 in 10,000

There are approximately 10,000 three-leaf clovers for every four-leaf one. Some people find them regularly — which says more about their patience than their luck.

Source: Generally cited botanical estimate.

Two people sharing a birthday in a room of 23

> 50%

This is the Birthday Paradox. Most people guess the group needs to be much larger. The full interactive is below.

A meteor striking your house in a given year

1 in 182,138,880,000,000

Approximately one meteorite falls per 500,000 km² per year. A house is about 100m². The maths is humbling. (Approximate estimate.)

Source: Derived from known meteorite fall rates and average house footprint.

Solving a scrambled Rubik's Cube by random moves

1 in 43,252,003,274,489,856,000

There are 43 quintillion possible Rubik's Cube states. Solving one by random moves is so unlikely it has never happened and almost certainly never will.

How many people until two share a birthday?

The answer surprises almost everyone.

People in the room: 23

50.7%

chance of a shared birthday

In a room of 23 people, there's a 50.7% chance two share a birthday. In a room of 70, it's 99.9%.

This works because you're not asking "does anyone share my birthday?" — you're asking "does any pair share a birthday?" With 23 people there are 253 possible pairs. Each pair has a 1 in 365 chance of matching. The combinations add up fast.

What are the odds?