Singapore's six-digit postal code system

The postal code currently used in Singapore is the six-digit postal code. It was introduced on 1 September 1995 to replace the four-digit code system to facilitate further automation of the mail-sorting system. The previous four-digit postal code still required 48 percent of mail to be manually sorted. With projected mail volume increasing six percent annually, Singapore Post saw the need for increased automation to raise postal standards and to cut manpower expended. The new mail system has reduced manual sorting to 17 percent. This is made possible by the adoption of the six-digit postal system. Manual sorting is still needed for incomplete addresses or if envelopes are flimsy or of an odd size.

The six-digit postal code enables the generation of one million numbers essential to cover the unique numbers of all Singapore delivery points. The four-digit postal code system could generate numbers for only 10,000 delivery points. Each delivery point, a house, building or block of flats is given its own identifying number. It also allows Singapore Post to provide postal codes for future housing developments until 2002 at least.

Mechanism of the digits
Singapore first adopted a postal code system in 1950. The two-digit postal code system divided the island into 28 postal districts. The four-digit system subsequently replaced the two-digit system in July 1979, subdividing the 28 districts into 80 postal sectors. The first two digits indicate the postal districts and the last two indicate the postal sectors. With the opening of Changi Airport, the number of postal sectors increased to 81.

The district postal code, which is the first two digits of the four-digit system, was made obselete when the six-digit system was introduced on 1 September 1995, so it was dropped. The six-digit postal code consists of two parts: the last two digits (sector code) of the old four-digit postal code, and followed by last four new digits referring to the number of the delivery point. The number of the delivery point are residential block numbers or numbers assigned to private houses and buildings that are numbered according to the alphabetical order of street names.

State-of-the-art sorting machine
Previously, mails had to first be sorted out according to postal sectors. The mails were then manually sorted according to the postman's beat in that sector, then the postman collected the mail for his beat and sorted them out by streets and apartment blocks before finally arranging them in the sequence of delivery. In September 1998, Singapore Post acquired a S$100-million system to automate mail sorting at the new centre at Eunos Road 8. With the new six-digit system, the state-of-the-art machine could complete the above processes in a matter of seconds.

Preparations for the six-digit system
Singapore Post prepared the country for the use of the six-digit postal code system. Organisations with large databases were given free software to help convert the old codes to new ones. Besides distributing the new postal code directory for free, Singapore Post also launched an easy-to-use automated, speech-enabled Postal Code Helpline system on 16 April 2002. The Postal Automated Machines could also provide postal code information.

As a result of effective automation and other new value-added services, Singapore Post is able maintain postal rates in Singapore. During the financial year 2003/2004, Singapore Post delivered 98.8 percent of mails posted to addresses within the Central Business District as well as 99.1 percent of mails posted to all other addresses within the very next day.

To mark the introduction of the six-digit postal code system, the Singapore Philatelic Bureau released the "Six Digit Postal Code Commemorative Stamp" issue in September 1995, which comprises two stamps depicting the development of the postal code system from two to six digits.

Joshua Chia


A brief history of Singapore post. (n. d.). Retrieved December 13, 2004, from 

Lim, S. (1992, February 18). $100 m system to automate mail sorting. The Straits Times, p. 1. Retrieved from NewspaperSG.

New collection of stamps sticks to Singapore's past. (1995, December 5). The Straits Time, Life!, p. 5. Retrieved from NewspaperSG.

6-digit postal code commemorative stamp issue. (1995, June-July). Philatelic News.
(Call no.: RSING 383.95957 SP)

Seng, L. P. (2002). SingPost launches speech-enabled helpline. Retrieved December 13, 2004, from

S'pore Telecom explains need for six-digit postal codes. (1992, February 18). The Business Times, p. 3. Retrieved from NewspaperSG.

Telecommunications Authority of Singapore annual report 1996/1997. (1997). Singapore: Telecommunication Authority of Singapore.
(Call no.: RSING 384 SIN- [AR])

Telecommunication Authority of Singapore annual report 1995/1996. (1996). Singapore: Telecommunication Authority of Singapore.
(Call no.: RSING 384 SIN- [AR])

The information in this articles is valid as at 2006 and correct as far as we are able to ascertain from our sources. It is not intended to be an exhaustive or complete history of the subject. Please contact the Library for further reading materials on the topic.

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