Every month when your electricity bill arrives, it’s often confusing to understand how the total amount is calculated.
Many people just pay the bill without realizing how their usage affects the final cost.
But what if you could calculate your electricity units and estimate your monthly bill yourself — even before it arrives?
In this guide, you’ll learn exactly how to do that, step-by-step, using simple math and real-life examples.
🧮 What Are Electricity Units?
Electricity units are measured in kilowatt-hours (kWh) — which means the amount of electricity used by a 1,000-watt appliance in one hour.
For example:
- If you use a 1000-watt (1kW) appliance for 1 hour, you’ve consumed 1 unit of electricity.
- If you use a 100-watt bulb for 10 hours, that’s also 1 unit (100 × 10 = 1000 watt-hours = 1 kWh).
So, each “unit” on your bill represents one kilowatt-hour (kWh) of energy consumed.
⚙️ Formula to Calculate Electricity Units
Here’s the basic formula:
Units (kWh) = Wattage of Appliance × Hours Used
1000
Let’s break it down with an example.
Example:
You use:
- A 100-watt fan for 8 hours daily
- A 50-watt LED light for 6 hours daily
- A 1500-watt iron for 30 minutes daily
Now, let’s calculate:
| Appliance | Power (Watts) | Hours Used | Energy Used (kWh) |
|---|---|---|---|
| Fan | 100 | 8 | (100 × 8) ÷ 1000 = 0.8 |
| LED Light | 50 | 6 | (50 × 6) ÷ 1000 = 0.3 |
| Iron | 1500 | 0.5 | (1500 × 0.5) ÷ 1000 = 0.75 |
Total Units Per Day = 0.8 + 0.3 + 0.75 = 1.85 units
Total Units Per
Month = 1.85 × 30 = 55.5 units
So, this setup consumes about 55.5 electricity units per month.
💰 How to Estimate Your Monthly Bill
Once you know your total units, multiply them by your per-unit rate, which depends on your electricity provider and usage slab.
In Pakistan, the residential per-unit rates (2025) approximately are:
| Slab | Units Range | Rate per Unit (PKR) |
|---|---|---|
| 1 | 1 – 100 | 7.74 |
| 2 | 101 – 200 | 10.06 |
| 3 | 201 – 300 | 12.15 |
| 4 | 301 – 700 | 19.55 |
| 5 | Above 700 | 22.65 |
(Note: Rates vary slightly by company and government updates.)
Example Calculation:
You consumed 55.5 units in a month.
Since you fall in the first slab (1–100 units):
55.5×7.74=Rs.429.57
Now add meter rent (Rs. 8) and TV fee (Rs. 35):
429.57+8+35=Rs.472.57
✅ Estimated Monthly Bill = Rs. 473
🔋 Quick Reference Table for Common Appliances
| Appliance | Power (Watts) | Average Daily Use (Hours) | Units per Month (Approx.) |
|---|---|---|---|
| Ceiling Fan | 100 | 8 | 24 |
| LED Bulb | 20 | 6 | 3.6 |
| Refrigerator | 300 | 24 | 216 |
| Air Conditioner (1 Ton) | 1200 | 6 | 216 |
| Iron | 1500 | 0.5 | 22.5 |
| Washing Machine | 500 | 1 | 15 |
(Values are estimates and may vary based on brand and efficiency.)
🌿 Tips to Reduce Your Electricity Units
If your bills seem too high, here are easy ways to reduce your unit consumption:
- Switch to LED lights – They use 75% less power than bulbs.
- Turn off appliances when not in use.
- Use energy-efficient fans and air conditioners (Inverter type).
- Run washing machines and irons during off-peak hours.
- Unplug chargers and adapters – they draw small but continuous current.
📱 Online Unit Calculators
If you don’t want to calculate manually, try these free tools:- https://bill.pitc.com.pk For estimated billing info
- Online Electricity Bill Calculator (Pakistan) – Search on Google for instant results.
Just enter your unit consumption, and it will estimate your total cost instantly.
🧠 Frequently Asked Questions
Q1: What is one unit of electricity?
One unit = 1 kilowatt-hour (1 kWh), which is the energy used by a 1000W appliance in 1 hour.
Q2: How can I check my electricity units from my bill?
Look for the “Current Reading” and “Previous Reading.” Subtract the two to find total units consumed.
Q3: Why do electricity rates increase with more units?
Because of slab-based billing — higher usage falls into higher per-unit rates.
Q4: Can I reduce my bill without reducing usage?
Yes. Use inverter ACs, energy-efficient appliances, and off-peak usage to lower cost per unit.
⚡ Final Thoughts
Learning how to calculate electricity units helps you take control of your energy consumption.
Once you understand the math behind your bill, you can easily plan your usage, reduce waste, and even predict next month’s cost.
Electricity isn’t just about payment — it’s about smart usage.
Be energy-aware, and you’ll see the difference in your savings every month!