How many solar panels do you need? This solar panel calculator shows the number of plates for every common size, from 550W to 720W, along with the real system size, roof space and today’s panel cost. Enter a system size in kW, or your monthly units if you’re not sure.
Solar Panel Calculator
System size ya monthly units daalein, har panel size ke liye ginti dekhein.
| Panel | Panels needed | Actual size | Roof space | Panel cost |
|---|
Panel cost uses today's average A-grade rate. Roof space includes walking room for cleaning.
How many solar panels for 3kW, 5kW and 10kW?
| System | 585W panels | 620W panels | 720W panels |
|---|---|---|---|
| 3 kW | 6 | 5 | 5 |
| 5 kW | 9 | 9 | 7 |
| 8 kW | 14 | 13 | 12 |
| 10 kW | 18 | 17 | 14 |
| 15 kW | 26 | 25 | 21 |
Counts are rounded up so the system meets or slightly exceeds the target size.
How the calculator works
- From kW: panels = system size (W) ÷ panel wattage, rounded up.
- From units: system size = (monthly units ÷ 30) ÷ (5 sun hours × 80%), rounded up to the nearest 0.5 kW.
- Roof space: about 2.6 m² per standard panel (3.1 m² for 700W+ large panels), plus 15% walking room.
- Cost: panels only, at today’s average A-grade rate of Rs 41 per watt.
Bigger panels or more panels?
Large 700W+ panels mean fewer plates and less wiring, but they are heavier, need stronger structures and may not fit smaller roofs or tight spaces. For most homes, 585–620W panels are the easiest balance of size, price and availability. Compare current rates in the 585W panel price guide.
Check your roof first
- Panels should face south with no shade between 9 am and 4 pm.
- Water tanks, stair rooms and neighbouring buildings can shade part of the array; leave space around them.
- Use our tilt angle calculator to set the best angle for your city.
Frequently asked questions
How many solar panels are needed for a 5kW system?
Nine 585W panels (5.27 kW), nine 620W panels (5.58 kW) or seven 720W panels (5.04 kW).
How many panels do I need for 500 units a month?
About 4.5 kW of solar, which is 8 panels of 585W in most Pakistani cities.
How much roof space does a 10kW system need?
Roughly 550–600 square feet with 585W panels, including space to walk and clean.
Prices and rules change often. This page was last reviewed on 12 November 2026. Spotted an outdated rate? Tell us and we'll update it.