How to Read a TNB Electricity Bill: kWh, AFA and Billing Days
In this guide
Four bill fields to check first
| Bill field | What to check |
|---|---|
| Previous and current meter readings | Compare the difference with kWh for the period; check whether the reading is estimated. |
| Current usage, kWh | Record the stated total; do not convert the RM amount into kWh using one flat rate. |
| Billing days | Record the actual period before comparing usage across bills. |
| Billing month | AFA depends on the month; two bills with the same usage can show different AFA values [source]. |
Betulkex — Bill worksheet for quote comparison
Record each bill separately
Do not combine several months into one figure. For each bill, record the start and end dates, billed days, previous and current meter readings, total kWh, billing month, supply phase shown, and whether the reading is actual or estimated. Mark estimated readings so the installer can see that the input has not yet been confirmed by an actual reading. Use the same bills for every quote.
| Betulkex field | Record from the actual bill |
|---|---|
| Month and period | Billing month and the printed start and end dates. |
| Billed days | Days shown on that bill; keep the actual period in your record. |
| Meter readings | Previous and current readings; mark any estimate. |
| Usage | Printed total kWh, not a guess derived from the RM amount. |
| Supply | Phase shown, or note that you have not identified it yet. |
For usage comparison only, kWh × 30 ÷ billed days gives a 30-day equivalent [source]. Use it only to compare periods; it is not TNB’s charge formula or a forecast of post-installation usage. Ask each installer to use the same bill periods and state generation, on-site self-use and export assumptions separately in writing. If a proposal uses only the RM total, ask it to show the kWh and billing period used first.
If the bill amount changes unexpectedly
First check whether the bill covers more days, uses an estimated meter reading, or shows a change in total kWh. Then check whether usage crossed the AFA threshold and which billing month determines the adjustment. The RM amount alone does not show whether the change came from usage, billing-period length or a monthly adjustment.
To prepare for a solar quotation, note kWh and billed days from consecutive bills and identify the supply phase shown. The installer still needs to design for the site and state generation, self-use and export assumptions in writing.
For the next step, use the home solar quotation guide to organize the fields to request and compare.
After solar is installed, a bill may show grid imports and export credits under the applicable programme rules. Do not assume export credits equal the full import rate; check the bill month and current programme documents [source].
Read also: solar hub
Frequently asked questions
How do I read a TNB electricity bill?
Start with previous and current meter readings, total kWh, billed days and billing month. Then inspect the charge lines on the actual bill. These four fields alone do not recalculate every charge, and the RM amount alone does not establish your kWh usage.
Why do my bills cover different numbers of days?
Check the start date, end date and billed days on each bill. For usage comparison only, kWh × 30 ÷ billed days gives a 30-day equivalent [source]. This is a local comparison method, not the TNB charge calculation; retain actual kWh and billed days for the installer.
What does AFA mean on a bill?
AFA is a fuel adjustment whose value changes by month. The referenced record says it applies when monthly usage exceeds 800 kWh [source]; check the value and month on your own bill because a dated figure does not represent another month [source].
What should I give a solar installer for a quotation?
Use the kWh and billed days shown on the actual bill, and identify the bill month. Do not use the RM amount alone to guess usage or system size.