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validation
United Kingdom Postcode Regex
Validates official UK postcodes across all outward and inward alphanumeric sectors.
Regular Expression Pattern:
/^[A-Z]{1,2}[0-9][A-Z0-9]? ?[0-9][A-Z]{2}$/i
Valid Match Example:
SW1A 1AA
Invalid / Non-Match Example:
12345
Regex Syntax Breakdown & Explanation
- •^[A-Z]{1,2}[0-9][A-Z0-9]? : Outward code representing postal area and district
- • ? : Optional spacing
- •[0-9][A-Z]{2}$ : Inward code pinpointing street unit
Implementation in Popular Languages
JavaScript / TypeScript
const regex = /^[A-Z]{1,2}[0-9][A-Z0-9]? ?[0-9][A-Z]{2}$/i;
const isValid = regex.test("SW1A 1AA");
console.log(isValid); // truePython (re)
import re
pattern = r"^[A-Z]{1,2}[0-9][A-Z0-9]? ?[0-9][A-Z]{2}$"
match = re.match(pattern, "SW1A 1AA")
print(bool(match)) # TrueGo (regexp)
package main
import (
"fmt"
"regexp"
)
func main() {
re := regexp.MustCompile(`^[A-Z]{1,2}[0-9][A-Z0-9]? ?[0-9][A-Z]{2}$`)
fmt.Println(re.MatchString("SW1A 1AA"))
}Frequently Asked Questions
Frequently Asked Questions
Everything you need to know regarding specifications, syntax, and security best practices.
The regular expression pattern is /^[A-Z]{1,2}[0-9][A-Z0-9]? ?[0-9][A-Z]{2}$/i. Validates official UK postcodes across all outward and inward alphanumeric sectors.