stackyFACTS
Travel

The hidden math that checks your passport number

HERE’S THE INTERESTING PART

That random string of digits on your identity page is actually a deeply mathematical formula. The final numbers are calculated using an algorithmic checksum of the previous digits, meaning border software can instantly detect a forged number without even checking a database.

The hidden math that checks your passport number
STACKY / Travel
One discovery leads to another.

Keep exploring facts in this topic.

Travel →
STACKY FOR IPHONE

A bigger world.
One discovery
at a time.

Keep discovering with Stacky. Interesting facts in an app that is always within reach.

Download on the App Store
ONE MORE DISCOVERY?

Keep exploring

All in this topic →
Your passport belongs to the government
Travel

Your passport belongs to the government

It feels like your most personal possession, yet your country’s issuing authority legally owns that little booklet. They graciously let you carry it around,…

Discover more
Children require new passports every five years
Travel

Children require new passports every five years

Bureaucracy refuses to acknowledge that aging is a natural process, demanding a fresh biometric scan of your offspring constantly. Because a toddler’s facial…

Discover more
Global passports generally only come in four primary colors—red, blue, green, and black—because they must meet strict international standards set by the International Civil Aviation Organization.
Travel

Global passports generally only come in four primary colors—red, blue, green, and black—because they must meet strict international standards set by the International Civil Aviation Organization.

Global passports generally only come in four primary colors—red, blue, green, and black—because they must meet strict international standards set by the…

Discover more
Queen Elizabeth II traveled to over 100 countries during her reign without ever holding a passport, simply because all British passports were officially issued in her name so she…
Travel

Queen Elizabeth II traveled to over 100 countries during her reign without ever holding a passport, simply because all British passports were officially issued in her name so she…

Queen Elizabeth II traveled to over 100 countries during her reign without ever holding a passport, simply because all British passports were officially…

Discover more
Why passports are a surprisingly recent invention
Travel

Why passports are a surprisingly recent invention

For most of human existence, you could simply hop on a ship and walk into another country without presenting a tiny booklet of official stamps. The concept of…

Discover more
Passports issued by most modern nations contain highly intricate, ultraviolet-reactive artwork that only border security guards are allowed to look at.
Travel

Passports issued by most modern nations contain highly intricate, ultraviolet-reactive artwork that only border security guards are allowed to look at.

Passports issued by most modern nations contain highly intricate, ultraviolet-reactive artwork that only border security guards are allowed to look at.…

Discover more
StackyMore discoveries in the app
Download on the App Store