How to Calculate Your Electricity Bill Step by Step

Your electricity bill is not a black box. Every rupee on it follows a predictable calculation that you can reproduce yourself with a pen and paper — or a phone calculator. Knowing the formula lets you catch errors, understand slab jumps, and plan consumption before the cycle closes.

Step 1: Find Your Monthly Units Consumed

Units consumed = Current meter reading − Previous meter reading.

Both readings are printed on your bill. If you read your own meter today, subtract the 'previous reading' figure on your last bill from today's meter display — that gives you units used so far this cycle.

• Current reading: the meter display now (or 'present reading' on the bill)
• Previous reading: the 'previous reading' figure on the bill
• Difference: your units for this billing period
• Example: current 4,820 − previous 4,650 = 170 units consumed

Step 2: Determine Your Tariff Category

Your tariff category is printed on your bill near the consumer name, as a code like A-1 (domestic single-phase), A-2 (domestic three-phase), B (commercial), or others. For most homes it is A-1 or A-1a.

Within A-1, you are either Protected (≤200 units/month for the last 6 months) or Unprotected. Protected consumers pay significantly lower rates. The word 'Protected' or 'Unprotected' appears explicitly on your bill.

Step 3: Apply the Slab Rates

NEPRA's residential slab rates divide consumption into bands, each with its own per-unit price. The exact PKR amounts change quarterly — always check nepra.org.pk for the current figures. The structure below illustrates how the slabs work; use your bill's 'tariff schedule' section for the exact rates that applied to your cycle.

For Protected consumers (≤200 units/month consistently): there are typically two or three lower-rate slabs covering 0–50, 51–100, and 101–200 units.

For Unprotected consumers: slabs typically begin at a higher base rate and escalate at 100, 200, 300, 400, 500, 600, and 700-unit thresholds.

Critical rule: if your consumption crosses into a new slab band, NEPRA's current rules mean the entire bill may be recalculated at the new rate — not just the units past the boundary. This is the 'slab jump' effect. Check your actual bill or your DISCO's tariff schedule to confirm which method applies to your category.

• Write down your total units (from Step 1)
• Identify which slab band(s) your consumption falls into
• Multiply units in each band by that band's per-unit rate
• Add the band totals together to get the base energy charge
• Example: 170 units unprotected — if units 1–100 are billed at Rs. X and units 101–200 at Rs. Y, calculate each band separately, then sum

Step 4: Add the Fixed Charges

Beyond the energy charge, every PITC-billed electricity connection pays several fixed monthly amounts regardless of consumption:

• Meter rent: a small flat charge for the meter itself (varies, typically Rs. 10–50/month)
• Fixed monthly service charge: set by NEPRA per tariff category
• TV/PTV licence fee: Rs. 35 per month, collected by DISCOs on behalf of Pakistan Television Corporation

Step 5: Add the Variable Surcharges

These are per-unit charges added on top of the base energy charge. They appear as line items on every bill.

• FPA (Fuel Price Adjustment): set monthly by NEPRA, can be positive (surcharge) or negative (credit), applied per unit consumed
• TRS (Tariff Rationalization Surcharge): a government surcharge per unit
• FC Surcharge (Financing Cost): another per-unit government levy
• Electricity Duty (ED): a provincial tax, typically a small percentage of the sub-total

Step 6: Calculate GST

General Sales Tax at 17% (for unprotected consumers) is applied to the subtotal of energy charges plus surcharges. Protected consumers in the lowest slab tiers may be exempt or have a lower GST rate — this varies by NEPRA determination.

GST = (Energy charges + Surcharges) × applicable GST rate.

Step 7: Check for LPS (If Overdue)

If you are paying a bill that is already past its due date, a Late Payment Surcharge (LPS) is added. Your bill prints two total amounts: the on-time amount and the after-due-date amount (which includes LPS). LPS is typically calculated as a percentage of the overdue principal.

The final total = Energy charges + Fixed charges + FPA + TRS + FC surcharge + ED + GST + (LPS if late).

Worked Example

An unprotected household uses 170 units. Assume illustrative rates (check current NEPRA rates for actual figures): units 1–100 at Rs. 20/unit, units 101–200 at Rs. 22/unit. Energy charge: (100 × 20) + (70 × 22) = 2,000 + 1,540 = Rs. 3,540. Add meter rent Rs. 25, TV fee Rs. 35, FPA at Rs. 3/unit = Rs. 510, TRS at Rs. 0.50/unit = Rs. 85. Subtotal before GST: Rs. 4,195. GST 17%: Rs. 713. Bill total: approximately Rs. 4,908.

Your actual bill may differ because NEPRA rates change quarterly and your specific connection may have additional line items. The principle is the same — every line is calculable. If your computed total differs significantly from what the bill shows, visit your DISCO's SDO office with your meter readings and ask for a bill breakdown.