Singapore's six-digit postal code system

The postal code currently being used in Singapore is the 6-digit postal code. It was introduced on 1 September 1995 to replace the 4-digit code system to facilitate further automation of the mail sorting system. The previous 4-digit postal code still required 48% of mail to be sorted manually. With projected mail volume increasing 6% annually, Singapore Post (SP) saw the need for increased automation to raise postal standards and to cut manpower used. The new mail system has reduced manual sorting to 17%. This is made possible by the adoption of the 6-digit postal system. Manual sorting is still needed for incomplete addresses or if envelopes are flimsy or of an odd size.

The 6-digit postal code enables the generation of one million numbers essential to cover the unique numbers of all Singapore delivery points. The 4-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 (SP) to provide postal codes for future housing developments until 2002 at least.

The mechanism of the digits
Singapore first adopted a postal code system in 1950. The 2-digit postal code system divided the island into 28 postal districts. The 4-digit system replaced the 2-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 4-digit system was obselete to the 6-digit system so it was dropped. The 6-digit postal code consists of two parts; namely (i) the last two digits (sector code) of the old 4-digit postal code, and then (ii) followed by last four new digits which is  number of the delivery point. The number of the delivery point are residential block numbers or numbers assigned to private houses and buildings numbered according to the alphabetical order of street names they are located in that sector.

The state-of-the-art sorting machine
Previously mails had to be firstly 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 sequence of delivery. In September 1998, Singapore Post (SP) acquired a $100 million system to automate mail sorting at the new centre at Eunos Road 8. With the new 6-digit system, the state-of-the-art machine could complete the above processes in a matter of seconds.

Preparations for the 6-digit system
SP prepared the country for the use of the 6-digit postal code system. Organisations with large databases were given free software to help convert the old codes to new ones. SP distributed the new postal code directory for free. It also created a Postal Code Helpline. The Postal Automated Machines (PAMs) could also provide postal code information. In 16 April 2002, SP launched an easy-to-use automated speech-enabled Postal Code Helpline system.

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

To mark the introduction of the 6-digit postal code system, the Singapore Philatelic Bureau released the Six Digit Postal Code Commemorative Stamp issue in September 1995. It comprised 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 http//

Lim, Serene. (1992, February 18). $100 m system to automate mail sorting. The Straits Times, p. 1. Retrieved on February 9, 2011, from NewspaperSG.

New collection of stamps sticks to Singapore's past. (1995, December 5). The Straits Time, Life!, p. 5. Retrieved on February 9, 2011, 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). Business Times, p. 3. Retrieved December 13, 2004, from Factiva database.

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.

Postal codes--Singapore
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