The single most useful thing to understand about a TNB bill is that it is not a price — it is a stack. Six or seven separate charges get added together, and at least two of them switch on and off entirely depending on how many kilowatt-hours you burned that month.
Which means the same household can cross an invisible line, use only slightly more electricity, and watch the bill jump by more than the extra usage should cost. Here is what each line does.
1. The 600 kWh line decides half your bill
This is the threshold that matters more than any rate.
According to figures reported by Malay Mail from TNB, around 85 per cent of domestic customers use 600 kWh or less per month, and those customers are exempt from three things at once: the Automatic Fuel Adjustment surcharge, the retail charge, and the 8 per cent SST.
Cross 600 kWh and all three switch on. Not on the excess — on your consumption within the applicable structure. That is why bills can look disproportionate the month someone finally leaves the aircon on overnight.
If your usage sits between 550 and 650 kWh, this one number is worth more attention than any other line on the page.
2. AFA is the number that moves every month
The Automatic Fuel Adjustment is the monthly surcharge that reflects what it actually cost to generate your electricity — fuel prices and the ringgit-dollar rate, mostly.
Recent declared rates:
| Month | AFA rate |
|---|---|
| June 2026 | +2.59 sen/kWh |
| July 2026 | +3.59 sen/kWh |
| August 2026 | +3.80 sen/kWh |
The arithmetic is simple. Multiply the rate by your consumption. At +3.59 sen/kWh and 400 kWh of usage, that is RM14.36 added to the bill.
Two things worth knowing. TNB publishes a rolling forward projection, and those projections get revised — the figures published in July for later months were subsequently revised downward. Treat any forecast as a projection, not a rate; the Energy Commission declares the final number.
Part of the July 2026 increase was also cushioned by a RM206 million contribution from the Electricity Industry Fund. That buffer is a policy decision, not a guarantee.
3. The Energy Efficiency Incentive is a discount most people never notice
Under the RP4 tariff structure that took effect on 1 July 2025, domestic customers using under 1,000 kWh a month qualify for the Insentif Cekap Tenaga, or Energy Efficiency Incentive.
It works in reverse to what you would expect. The lower your consumption, the bigger the per-unit discount, up to a maximum of 25 sen/kWh at the lowest usage bands. Use more, get less.
This creates a middle tier that is easy to miss. Between 601 and 1,000 kWh a month you have lost the AFA exemption but you still keep the efficiency incentive. Above 1,000 kWh, you have neither.
4. The energy charge is the part you actually control
This is the generation cost of the electricity you used, and it is the only line that responds directly to behaviour.
Under RP4, the domestic energy charge is roughly 44.43 sen/kWh for usage up to 1,500 kWh a month, stepping up to about 54.43 sen/kWh above that — before AFA, the efficiency incentive and everything else is applied.
Everything else on this list is either a fixed charge, a policy adjustment or a levy. This is the line that shrinks when you change the aircon setpoint.
5. Capacity and network charges are not your usage
Two charges that confuse people because they do not feel like consumption.
The capacity charge covers payments under power purchase and service level agreements — effectively the cost of keeping generation capacity available whether or not you use it. The network charge covers the transmission and distribution system that gets the electricity to your meter.
You cannot behave your way out of either. They are structural. Knowing that stops you from hunting for a phantom appliance when the bill looks high.
6. The retail charge and the 8 per cent SST
The RM10 monthly retail charge is the administrative cost of billing you. It is waived automatically for anyone using 600 kWh or less per month.
The 8 per cent SST follows the same threshold — under 600 kWh, it does not apply.
Neither is large on its own. Together with the AFA they are why the 600 kWh line has three separate teeth.
7. KWTBB, and the second cliff at 300 kWh
The Kumpulan Wang Tenaga Boleh Baharu levy funds renewable energy development and appears as a small line item on most bills.
Customers using 300 kWh or less a month are exempt from it. That makes 300 kWh a second, quieter threshold below the main one — relevant mostly to smaller households, single occupants and anyone living somewhere with no aircon.
Time of Use: only worth it if you actually shift
TNB offers Time of Use tariffs, where the price varies by when you consume rather than how much.
On the domestic ToU structure, peak hours run 2pm to 10pm Monday to Friday, with off-peak covering 10pm through to 2pm the following day, plus weekends.
The maths only works if you genuinely move load. Laundry, water heating, dishwashing and EV charging are the shiftable ones. Aircon during a Malaysian afternoon is not — and that is the single biggest household load, which is why ToU suits fewer homes than the brochure suggests. If you are running an EV at home, the calculation changes considerably, and it interacts with the other running costs we listed in car ownership costs that are not the instalment.
What to do with all this
Three practical moves, in order of impact.
- Find your monthly kWh, not your monthly ringgit. It is printed on the bill. That number tells you which side of 600 you are on, which is the fastest way to understand your total.
- Attack the aircon before anything else. Raising the setpoint to 24–26°C, running a fan alongside it, and cleaning filters monthly all reduce the energy charge, which is the only line that responds.
- Check the declared AFA rate, not the forecast. The Energy Commission publishes the final figure monthly. Forecasts have moved substantially in 2026.
None of this is a reason to panic about one high month. Bills move with the weather. But a structural increase shows up as a change in kWh, and that is checkable.
For how other fixed household costs have shifted this year, see the 2026 SST changes and the emergency fund advice Malaysians actually get.
FAQ
Why did my TNB bill suddenly go up this month?
The two usual causes are crossing the 600 kWh threshold — which switches on the AFA surcharge, the RM10 retail charge and 8 per cent SST at the same time — or a rise in the declared AFA rate. Compare your kWh figure against last month's before assuming a rate change.
What is AFA on my TNB bill?
The Automatic Fuel Adjustment, listed as Pelarasan Bahan Api Automatik. It is a monthly surcharge in sen per kWh reflecting fuel and foreign exchange costs in generation. It was +3.80 sen/kWh for August 2026, up from +3.59 sen/kWh in July.
Who is exempt from AFA?
TNB has stated that domestic customers using 600 kWh or less per month — around 85 per cent of households — are exempt from AFA, the retail charge and the 8 per cent SST.
How do I calculate the AFA charge myself?
Multiply the declared rate by your monthly consumption. At +3.59 sen/kWh and 400 kWh, that is 1,436 sen, or RM14.36.
Is Time of Use cheaper than the normal tariff?
Only if you can move significant consumption into off-peak hours. Peak runs 2pm to 10pm on weekdays. Households whose largest load is daytime aircon usually see little benefit.
Sources: Malay Mail on the AFA fuel surcharge, Paul Tan on the August 2026 AFA rate, Suruhanjaya Tenaga, Tenaga Nasional Berhad.
