Electricity Bills in Pakistan: Slab Formula & Worked 350-Unit Example
Your bill is not one rate times your units. It is slab-wise: the first 100 units at one rate, the next 100 at a higher rate, and so on — plus fixed charges. This guide shows the formula and a full worked bill.
Try it yourself: Electricity Bill Calculator — enter your units and consumer type for your own slab breakdown.
The formula
For a residential consumer, the calculator walks your units through the slabs in order, charging each chunk of units at that slab's rate, then adds the fixed charges of the highest slab you reached:
- Energy charges = sum over slabs of (units in slab × slab rate).
- Total bill = energy charges + fixed charges.
Residential slab rates used by the calculator (NEPRA notified, February 2026):
| Units up to | Rate (Rs/unit) | Fixed charges (Rs) |
|---|---|---|
| 100 | 22.44 | 275 |
| 200 | 28.91 | 300 |
| 300 | 33.10 | 350 |
| 400 | 36.46 | 400 |
| 500 | 38.95 | 500 |
| 600 | 40.22 | 675 |
| 700 | 41.85 | 675 |
| Above 700 | 47.20 | 675 |
Worked example: 350 units, residential
| Slab | Units | Rate | Amount |
|---|---|---|---|
| 1–100 | 100 | Rs 22.44 | Rs 2,244 |
| 101–200 | 100 | Rs 28.91 | Rs 2,891 |
| 201–300 | 100 | Rs 33.10 | Rs 3,310 |
| 301–350 | 50 | Rs 36.46 | Rs 1,823 |
Energy charges = Rs 2,244 + Rs 2,891 + Rs 3,310 + Rs 1,823 = Rs 10,268. Fixed charges for the 301–400 slab = Rs 400. Total bill = Rs 10,668.
Assumptions behind these figures
- Residential consumer, 350 units, NEPRA notified slabs (February 2026), as used by the calculator in October 2026.
- Fixed charges are those of the highest slab reached (Rs 400 for the 301–400 slab).
- The estimate excludes FCA, GST and surcharges — your actual bill will be higher by those amounts.
- Protected residential consumers get cheaper first-200 rates (Rs 10.54 and Rs 13.01); commercial consumers pay a flat Rs 46.50 per unit plus Rs 1,500 fixed charges. The calculator handles both.
Common mistakes
- Multiplying all units by the highest slab rate. Only the units inside each slab pay that slab's rate — the first 100 units always pay the lowest rate.
- Forgetting fixed charges. They are added on top of energy charges and rise with the slab you reach.
- Comparing with the printed bill and crying foul. FCA, GST and surcharges are real additions the estimate deliberately excludes — check your DISCO bill's breakdown before concluding the estimate is wrong.
- Using residential slabs for a commercial meter (or vice versa). Pick the right consumer type in the calculator.
Source and date note
The figures in this guide follow the Electricity Bill Calculator's slab rates (NEPRA notified, February 2026) as of October 2026. Tariffs are revised periodically, so verify the current slabs with your DISCO — and remember the estimate excludes FCA, GST and surcharges.
Related calculators
- Electricity Bill Calculator — your own slab-wise bill estimate.
- Solar System Size Calculator — how many kW covers your monthly units.
- UPS Load Calculator — what your UPS can run during load shedding.