Solar Load Calculator — Size Your Inverter & Panels
Add each appliance you want to run on solar, with wattage, quantity and daily hours. The calculator totals your peak load and daily energy and suggests an inverter and panel size.
Updated
Result
642 W · 8.37 kWh/day
Total load 642 W, 8.37 kWh/day — about a 1 kW inverter and 1.9 kW of panels
- Peak running load
- 642 W
- Daily energy
- 8.37 kWh
- Monthly energy
- 251 units
- Suggested inverter (load + 25%)
- 0.8 kW or more
- Solar panels to cover daily use
- 1.9 kW (4 × 585 W)
- Estimate only. Motors (pumps, fridges, ACs) need extra surge capacity when starting.
Results are estimates for planning. Actual figures depend on local conditions, prices and quotes — verify before making decisions.
Formula
Peak load (W) = Σ Watts × Quantity
Daily energy (kWh) = Σ Watts × Quantity × Hours ÷ 1000
Inverter ≈ Peak load × 1.25
Solar kW = Daily kWh ÷ (Sun hours × Efficiency)
The 25% margin on the inverter covers motor start-up surges (pumps, fridges, ACs) and future additions.
Examples
Example
4 fans (80 W, 12 h), 6 LED lights (12 W, 6 h), fridge (150 W, 24 h), TV (100 W, 5 h): peak 642 W, about 8.4 kWh/day — a ~1 kW inverter and ~1.9 kW of panels.
Reference table
| Appliance | Typical watts | Typical hours/day | Units/month (30 days) |
|---|---|---|---|
| AC 1 ton (non-inverter) | 1,100 | 8 | 264 |
| AC 1.5 ton (non-inverter) | 1,700 | 8 | 408 |
| AC 2 ton (non-inverter) | 2,300 | 8 | 552 |
| AC 1 ton (inverter, average) | 650 | 8 | 156 |
| AC 1.5 ton (inverter, average) | 950 | 8 | 228 |
| AC 2 ton (inverter, average) | 1,300 | 8 | 312 |
| Ceiling fan (AC motor) | 80 | 12 | 28.8 |
| Ceiling fan (DC inverter) | 35 | 12 | 12.6 |
| Pedestal fan | 60 | 8 | 14.4 |
| Air cooler | 200 | 10 | 60 |
| Refrigerator (average draw) | 150 | 24 | 108 |
| Deep freezer (average draw) | 200 | 24 | 144 |
| Microwave oven | 1,200 | 0.5 | 18 |
| Electric kettle | 1,800 | 0.25 | 13.5 |
| LED TV (43–55 inch) | 100 | 5 | 15 |
| Washing machine | 500 | 1 | 15 |
| Iron | 1,000 | 0.5 | 15 |
| Water pump (1 HP) | 750 | 1 | 22.5 |
| Desktop computer | 200 | 6 | 36 |
| Laptop | 60 | 6 | 10.8 |
| LED bulb | 12 | 6 | 2.2 |
| LED tube light | 20 | 6 | 3.6 |
| Wi-Fi router | 10 | 24 | 7.2 |
Important information
- Motors (pumps, fridges, ACs) can draw 3–6 times their running power for a second when starting; inverters must handle that surge.
- Run heavy loads like irons and pumps during sunny hours to use solar directly.
Frequently asked questions
What size inverter do I need?
At least your total running load plus about 25% margin, and enough surge capacity for motors.
Can I run an AC on solar?
Yes, but ACs are large loads. Inverter ACs are much easier to run on solar than non-inverter models.
What is the difference between kW and kVA?
kVA is apparent power; kW is real power. Inverters are often rated in kVA — with a typical power factor of 0.8, a 5 kVA inverter supplies about 4 kW.
Learn more
- How Many Solar Panels Do I Need? (Pakistan) — Size a home solar system from your electricity bill, understand peak sun hours and efficiency, and estimate payback.
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