Pro-Rata Billing in MEPCO Bills: How It Works and Why Your Units Look Different (2026)
Pro-rata billing means your electricity company converts the units on your meter into a standard 30-day month before it chooses your slab. If your meter was read after 33 days, the billed units are lower than the meter shows. If it was read after 28 days, they are higher. The aim is to stop an uneven reading gap from pushing you over 200 units.
This page shows the formula, worked examples, the common myths, and how to check it on your own bill.
How Pro-Rata Billing Is Calculated
The formula is simple: divide the units on the meter by the number of days in the billing period, then multiply by 30.
| Days between readings | Units on the meter | Calculation | Billed units |
|---|---|---|---|
| 28 days | 280 | 280 ÷ 28 × 30 | 300 |
| 31 days | 310 | 310 ÷ 31 × 30 | 300 |
| 33 days | 208 | 208 ÷ 33 × 30 | 189 |
| 33 days | 309 | 309 ÷ 33 × 30 | 281 |
In the third row the meter shows 208 units, which is above the 200-unit protected limit. After the adjustment the household is billed for 189 units, so it stays protected.
Why Pro-Rata Billing Exists
NEPRA’s rules treat the billing cycle as 30 days. In practice meter readers cannot visit on exactly the same date each month, so some bills covered 28 days and others 33 or more. Before this adjustment, that uneven gap could push a household over 200 units for reasons that had nothing to do with how much electricity it used. The adjustment evens this out.
Pro-Rata Billing: Myths and Facts
| Myth | Fact |
|---|---|
| Pro-rata billing means over-billing. | It only scales your units to 30 days. A long cycle lowers the billed units and a short cycle raises them. |
| It always protects my protected status. | It helps when the cycle is longer than 30 days. If the cycle is shorter, the units are scaled up and can cross 200. |
| The extra units are lost. | NEPRA’s manual is reported to carry the remaining units forward to the next bill. Check your next bill to see them. |
| It changes the tariff rate. | No. The rates stay the same. Only the units fed into the slab change. |
| The billed units must equal the meter photo. | They can differ. The bill shows the reading dates so you can check the adjustment. |
How to Check Pro-Rata Billing on Your MEPCO Bill
- Find the previous and the current reading dates on your bill.
- Count the days between them.
- Subtract the previous reading from the current reading to get the units on the meter.
- Divide those units by the days and multiply by 30.
- Compare the answer with the units billed. A difference of one or two units is normal rounding.
You can then test the result in our MEPCO bill calculator.
How Pro-Rata Billing Affects Protected Status
Protected rates apply when you use 200 units or less in every billing month of the past six months. The adjusted units are the ones used for that test, so the day count matters. A 33-day cycle with 208 units on the meter stays protected, while a 28-day cycle with 190 units on the meter is billed as about 204 units and can cross the line. See our protected and non-protected tariff guide for the full rule.
What to Do If You Think the Pro-Rata Adjustment Is Wrong
- Check the reading dates and the meter photo on your bill. NEPRA’s manual asks for a dated meter photo to be printed on the bill.
- Recalculate with the formula above and note the difference.
- Write to your sub-division office with the bill and your calculation. NEPRA’s manual gives the company 7 days to answer a complaint about a wrong reading or calculation.
- Keep your own monthly meter photo so that you can prove the reading dates.
For contact options, see our MEPCO helpline guide.
Last reviewed: October 2026. This is an independent informational website and is not affiliated with MEPCO, NEPRA or any government organization. Verify the calculation on your bill with your sub-division office.
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