How many digits is a South African postal code?

A South African postal code is exactly 4 digits, for example 0001 for central Pretoria or 8001 for central Cape Town. Codes below 1000 are written with leading zeros. Anything that is not 4 digits is not a valid postal code.

How are provinces mapped from the code?

South Africa Post Office assigns numeric ranges to provinces rather than using a single prefix digit. For example 0001–0299 sits in Gauteng/Pretoria and 7400–8099 covers the Western Cape. This validator matches the full 4-digit number against those ranges.

Why can one prefix span two provinces?

Because SAPO ranges are not strictly aligned to single leading digits, neighbouring provinces can share a leading digit. The validator therefore compares the whole numeric value against range boundaries instead of just the first digit, which gives a more accurate province.

Does a valid format mean the address is deliverable?

No. The tool confirms the 4-digit format and a province range, but it does not hold the full SAPO delivery database, so a structurally valid code may not be an active delivery point. Treat the province as a strong hint, not a delivery guarantee.

Is my data sent anywhere?

No. Validation and the province lookup run entirely in your browser with a built-in range table. Nothing is transmitted, so the tool is safe to embed in checkout flows that handle customer addresses.

South Africa Postal Code Validator

A South African postal code is a 4-digit number, and the South Africa Post Office (SAPO) assigns numeric ranges to provinces. Because the ranges do not line up neatly with a single leading digit, province lookup compares the whole 4-digit value against range boundaries. This tool validates the format and maps the code to a province in your browser.

How it works

Validation has two parts:

Format: after removing spaces, the value must be exactly 4 digits 0–9 (leading zeros allowed, e.g. 0001).
Province mapping: the 4-digit value is read as a number and matched against a built-in table of SAPO province ranges. For example 0001–0299 → Gauteng (Pretoria area), 7400–8099 → Western Cape.

If the number falls inside a known range, the province is reported; otherwise the format may be valid but the province is reported as out of the mapped ranges.

Example

0001  →  valid, Gauteng (Pretoria)
8001   →  valid, Western Cape (Cape Town)
4001   →  valid, KwaZulu-Natal (Durban)
123     →  invalid (only 3 digits)

Notes

The numeric-range lookup is more accurate than a single-digit prefix because South African ranges cross digit boundaries — but it is still a routing hint, not a guarantee that the exact code is an active SAPO delivery point. Use the province as a checkout sanity check, then confirm serviceability with the carrier. All processing is local.