In 2008 Cambodia Post made a postage uprate. According to the new postage guidebook published by the Ministry of Posts and Telecommunications, domestic letters up to 10g rose from 300r to 500r, 10g to 50g cost 800r. Then rates are calculated at 50g intervals:
050g to 100g - 1300r
100g to 150g - 1800r
150g to 200g - 2300r
200g to 250g - 2800r
The list goes on till 2kg. The charge is flat despite the dispatch distance. Illustrated below is a Phnom Penh postcard to Takhmau, the provincial capital of Kandal, bearing the basic 500r postage. Postcards and letters share the same postage rates.
This Phnom Penh intracity cover bears the 10g to 50g postage of 800r:
Registered service is available at 800r extra, it is only available at selected post offices, primarily the capital, provincial capitals and certain sub branches. Below features a registered cover from Takhmau to Phnom Penh with 1300r stamps for 500r under 10g domestic postage and 800r registration fee.
Below is another cover from the city of Battambang to Phnom Penh, 1350r paying the 500r domestic rate and 800r registered fee. Strange enough many post offices have stamp stock which fails to compile the exact postage for customers, the solution is just to get close to it, in this case there is a 50r surplus.
Unknown to most postal historians and philatelists, senders still pay 1300r to the postal clerk, not the face value of stamps. Sometimes post offices cheat customers but that is another story.
Some post offices do not have domestic registered ID labels (analog), the substitution is S10 code registration ID labels which are originally meant for international mail. This Stung Treng to Phnom Penh cover gives an example:
According to the face value of stamps, the letter has a postage surplus as well, but the actual payment can be a different case.
Cambodia Post also offers EMS service. EMS charges at very moderate rates: letters under 25g cost 6000r, 25g to 50g is 8700r, 0.5g to 1kg is 12000r. This is the reason why local businesses prefer EMS to usual delivery which is slow and unreliable.