Regex for Coordinates (Latitude/Longitude) — Pattern Explained with Examples

Geographic coordinate validation is essential for mapping applications, geocoding APIs, and location-based services. This pattern validates latitude and longitude pairs in decimal degrees format, enforcing the correct ranges: -90 to 90 for latitude and -180 to 180 for longitude.

The Pattern

/^-?([0-8]?\d(\.\d+)?|90(\.0+)?),\s*-?(1[0-7]\d(\.\d+)?|180(\.0+)?|[0-9]?\d(\.\d+)?)$/

Pattern Breakdown

Matches

• 37.7749, -122.4194
• 0, 0
• 90.0, 180.0
• -90, -180
• 51.5074, -0.1278

Does NOT Match

• 91, 0 (lat > 90)
• 0, 181 (lng > 180)
• 90.1, 0 (lat exceeds 90)
• -90.01, 0 (lat below -90)
• abc, 123

Language Examples

JavaScript

const coordRegex = /^-?([0-8]?\d(\.\d+)?|90(\.0+)?),\s*-?(1[0-7]\d(\.\d+)?|180(\.0+)?|[0-9]?\d(\.\d+)?)$/;
console.log(coordRegex.test('37.7749, -122.4194')); // true
console.log(coordRegex.test('91, 0'));               // false

Python

import re
pattern = r'^-?([0-8]?\d(\.\d+)?|90(\.0+)?),\s*-?(1[0-7]\d(\.\d+)?|180(\.0+)?|[0-9]?\d(\.\d+)?)$'
print(bool(re.match(pattern, '37.7749, -122.4194'))) # True
print(bool(re.match(pattern, '91, 0')))               # False

Common Pitfalls

• Decimal precision is flexible — 37.7749 (4 decimal places) and 51.5 (1 decimal place) both match, but remember that precision affects location accuracy (1 decimal place ≈ 11 km, 4 places ≈ 11 m)
• Degrees-Minutes-Seconds (DMS) format like 37°46'29"N, 122°25'09"W is completely different and requires a separate pattern
• Latitude-first convention (lat, lng) is standard in geographic systems, but some APIs use lng, lat — confirm the order expected by your data source
• The comma separator is required between latitude and longitude values
• The negative sign must immediately precede the number without a space — - 90 is not valid

Real-World Use Cases

• Geocoding API integration — validate user-entered coordinates before sending them to a geocoding service
• Map marker placement — ensure coordinates fall within valid ranges before rendering on a map
• GPS data logging — validate coordinate strings from GPS devices before storing in a database

FAQ

Related Patterns

Regex for Numbers Regex for URL