When you type a city name into a travel tool, you're introducing ambiguity. "Los Angeles" is a geographic area of over 500 square miles; the nearest airport to one part of it is LAX, while another part is closer to Long Beach or Burbank. A ZIP code — or its international equivalent — replaces that ambiguity with a specific, small geographic area, making every distance, time, and location calculation significantly more accurate.
This guide explains how postal codes work as travel-planning tools, what they enable in distance and airport calculators, and the formats used around the world.
Why Precision Matters in Distance Calculations
A city is not a point — it's an area. When a distance calculator uses "Chicago" as a starting point, it is measuring from a fixed central coordinate (usually the city hall or geographic centroid), which may be miles from your actual hotel, neighbourhood, or the suburb where you're staying.
A ZIP code or postal code reduces this to a very small area — usually a few blocks to a few square miles — giving a far more accurate starting or ending point for any distance or driving-time calculation. For a city like Chicago (covering 234 square miles) or Los Angeles (503 square miles), this difference can amount to 10–30 miles of calculated distance.
Using ZIP Codes With Our Tools
- Distance calculator (/distance): enter a ZIP code instead of a city name for the most precise straight-line and road distance between two specific locations rather than two city centres.
- Driving time calculator (/driving): a ZIP code start or end point gives a more accurate drive-time estimate, particularly for large metros where your actual start/end may be far from the city centre.
- Nearest airport finder (/airport): entering a ZIP code finds the truly closest airport to your specific location, not just to the city's geographic centre.
- Hotels near (/hotels-near): a ZIP code or address locates hotels near a specific point, more useful than a city search when you need accommodation near a venue, train station, or meeting location.
- Halfway point (/halfway): two ZIP codes give the midpoint between specific locations rather than the midpoint between two city centres.
Postal Code Formats Around the World
Most modern travel and mapping tools accept all of the above formats, though some older tools are US-centric and only accept 5-digit ZIP codes. If a tool does not accept your country's postal code, try the most specific address or coordinates instead.
| Country | Format | Example | Called |
|---|---|---|---|
| United States | 5 digits | 90210 | ZIP code |
| United Kingdom | Letters and numbers | SW1A 1AA | Postcode |
| Canada | Alternating letter-number | M5V 2H1 | Postal code |
| Australia | 4 digits | 2000 | Postcode |
| Germany | 5 digits | 10115 | Postleitzahl (PLZ) |
| France | 5 digits | 75001 | Code postal |
| Japan | 7 digits (formatted as 3+4) | 100-0001 | Yūbin bangō |
| Brazil | 8 digits (formatted as 5-3) | 01310-100 | CEP |
| India | 6 digits | 110001 | PIN code |
| Netherlands | 4 digits + 2 letters | 1017 AB | Postcode |
When a City Name Is Fine
Not every calculation needs a postal code. For high-level planning — "roughly how long to fly from London to Tokyo" or "which US states are within a 500-mile drive?" — a city or region is entirely adequate, and the precision of a postal code adds nothing.
Postal codes become valuable when you need precision: finding the specific nearest airport to a particular hotel; calculating whether the halfway point between two addresses is closer to one town or another; finding hotels within walking distance of a specific convention centre or train station.
Duplicate City Names
Another reason postal codes are useful: many city names are duplicated across a country or even within a state. There are 34 places called Springfield in the United States. There are multiple Newtons, Richmonds, and Springfields in the UK. A ZIP code or postal code makes the location unambiguous in a way a city name alone cannot.
Frequently Asked Questions
ZIP and postal codes identify a specific, small geographic area rather than an entire city — making distance calculations, nearest-airport searches, and halfway-point finders significantly more accurate. A 5-digit US ZIP code covers roughly 1–5 square miles, compared to hundreds of square miles for a large city.