Solar Calculator Pakistan 2026: Calculate Your System Size, Cost & Savings
By PSI Editorial · 7 min read · Updated September 2026
Atomic Summary: To calculate your solar system size in Pakistan, divide your monthly kWh consumption by 135 (30 days × 4.5 peak sun hours). A typical Pakistani home consuming 450 kWh/month needs a 3.3–4 kW system. A 5kW on-grid system costs Rs. 500,000–700,000 and saves Rs. 18,000–26,000/month. Payback period is 2.5–4 years at current tariffs.
Step 1: Find Your Monthly kWh Consumption
Your electricity bill from WAPDA (LESCO, FESCO, MEPCO, IESCO, PESCO) or K-Electric shows your monthly units consumed. Look for "Units Consumed" or "kWh" on the bill. If it shows only the amount charged, use these estimates:
| Monthly Bill (Rs.) | Approx. Units (kWh) | Recommended System | Est. Cost (Rs.) |
|---|---|---|---|
| 5,000–8,000 | 150–250 kWh | 1.5–2 kW | 200,000–300,000 |
| 8,000–15,000 | 250–400 kWh | 2.5–3 kW | 300,000–450,000 |
| 15,000–25,000 | 400–650 kWh | 4–5 kW | 450,000–700,000 |
| 25,000–45,000 | 650–1,100 kWh | 7–10 kW | 700,000–1,200,000 |
| 45,000+ | 1,100+ kWh | 10–15 kW | 1,000,000–1,800,000 |
Step 2: Calculate System Size (The Formula)
Here is the simple formula used by Pakistani solar installers:
🧮 System Size Formula
System kW = (Monthly kWh ÷ 30 ÷ Peak Sun Hours) × 1.2 safety factor
Peak sun hours in Pakistan: Karachi = 5.8 hrs, Lahore = 5.3 hrs, Islamabad = 4.9 hrs, Multan = 5.9 hrs, Quetta = 6.5 hrs
Worked Example — Lahore home with Rs. 22,000 monthly bill (550 kWh):
- Daily consumption: 550 ÷ 30 = 18.3 kWh/day
- Divide by Lahore peak sun hours: 18.3 ÷ 5.3 = 3.45 kW
- Add 20% safety factor: 3.45 × 1.2 = 4.1 kW — round up to 5 kW system
- Estimated system cost: Rs. 500,000–700,000 (on-grid)
- Monthly savings: Rs. 18,000–22,000
- Simple payback: 27–39 months (2.5–3.5 years)
Step 3: Estimate Monthly Savings
Your monthly savings depend on your electricity tariff slab. In 2026, Pakistani residential tariffs range from Rs. 20/unit (lower slabs) to Rs. 42+/unit (slab 5, high consumption). Use this table:
| System Size | Monthly Generation | Savings @ Rs. 25/unit | Savings @ Rs. 35/unit |
|---|---|---|---|
| 3 kW | 360–450 kWh | Rs. 9,000–11,250 | Rs. 12,600–15,750 |
| 5 kW | 600–750 kWh | Rs. 15,000–18,750 | Rs. 21,000–26,250 |
| 7 kW | 840–1,050 kWh | Rs. 21,000–26,250 | Rs. 29,400–36,750 |
| 10 kW | 1,200–1,500 kWh | Rs. 30,000–37,500 | Rs. 42,000–52,500 |
Step 4: On-Grid vs Hybrid — Which Is Right for You?
- On-grid (no batteries): Cheapest option. Works during sun hours only. Goes dark during load shedding. Best for homes with minimal load shedding or those in posh areas with reliable supply.
- Hybrid with batteries: Continues working during load shedding and at night. Costs Rs. 150,000–500,000 more for battery storage. Best for most Pakistani homes dealing with 4–12 hours of daily load shedding.
- Off-grid: No grid connection at all. Requires larger battery bank. Only practical for remote areas with no grid access.
Net Billing Impact on Savings Calculation (2026)
Since February 2026, NEPRA replaced net metering with net billing. This means:
- Excess solar units exported to the grid earn only Rs. 8.13/unit (down from Rs. 30–42/unit under old net metering).
- Your savings calculation should assume self-consumption only — do not bank on export income.
- Best practice: size your solar system to match your daytime consumption, not to maximize export.
- If you have excess production, batteries are now more financially attractive than grid export.
Use Our Interactive Solar Calculator
Visit PakSolarInsights Calculator to enter your exact bill amount and get a personalized system size recommendation, cost estimate, monthly savings, and payback period — all calculated for your specific city and DISCO tariff zone.
Frequently Asked Questions
How do I calculate what size solar system I need in Pakistan?
Divide your monthly kWh consumption by 30 (days) and then by 4.5 (average peak sun hours). Multiply the result by 1.2 for a 20% safety buffer. Example: 450 kWh/month ÷ 30 ÷ 4.5 × 1.2 = 4 kW system needed.
How much does a 5kW solar system save per month in Pakistan?
A 5kW solar system in Pakistan generates approximately 600–750 kWh per month. At the current tariff of Rs. 30–35/unit (high residential slab), monthly savings are Rs. 18,000–26,000. Payback period for an on-grid system is typically 2.5–3.5 years.
What is the formula for calculating solar savings in Pakistan?
Monthly savings = (System kW × Peak sun hours × 30 days) × Your electricity tariff per unit. For a 5kW system in Lahore: 5 × 5.3 × 30 = 795 kWh/month × Rs. 32/unit = Rs. 25,440/month savings (self-consumption assumed).
How do I calculate solar panel payback period in Pakistan?
Simple payback = Total system cost ÷ Monthly savings. For a Rs. 650,000 system saving Rs. 22,000/month: 650,000 ÷ 22,000 = 29.5 months (about 2.5 years). Hybrid systems with batteries have longer payback of 4–6 years due to higher upfront cost.
Related: Solar Panel Price · 5kW System Cost · Net Billing Guide 2026 · 3kW System Guide