Solar System Size Calculator for Pakistan — What kW Do You Actually Need?
The short version: divide the units on your electricity bill by about 120 and you have your kW. A 600-unit month needs roughly a 5 kW system; a 1,200-unit month needs about 10 kW. The calculator below does that division, rounds up to the nearest half kW, sizes a battery for the backup hours you ask for, and prints an indicative cost band at July 2026 Pakistani install prices.
Since net metering was replaced by net billing in February 2026, the right size is no longer "as big as your roof allows". Exports earn roughly Rs 11 a unit while imports cost Rs 50–65, so you size for the load you can actually consume in daylight — and then decide separately whether storage is worth it.
Rates on this page last reviewed 26 July 2026. Every field below is editable — the defaults are a starting point, not a claim about your bill. We sell no hardware and take no installer commission; see how we verify.
Recommended system: 5 kW with ≈ 5 kWh lithium storage
Indicative cost (Jul 2026 rates): on-grid Rs 550,000–Rs 700,000; add ≈ Rs 225,000 for the battery (Rs 40–55K/kWh). Under net billing, size for self-consumption — exports earn only ~Rs 11/unit.
How this calculator works — the actual arithmetic
- Generation: it assumes 1 kW of installed panels yields about 120 units a month after heat and dust derating. Our 5 kW system guide records 600–700 units/month and the 10 kW guide 1,250–1,450 units/month — that is 120–145 units per kW. The calculator uses the bottom of the band, so it errs towards a slightly larger system rather than a slightly smaller one.
- System size = monthly units ÷ 120, rounded up to the nearest 0.5 kW.
- Battery = (monthly units ÷ 30 ÷ 24) × backup hours × 1.25. The 1.25 covers depth-of-discharge and round-trip losses.
- Cost = Rs 110,000–140,000 per installed kW for on-grid, plus about Rs 45,000 per kWh for battery modules if you asked for backup.
Worked example — a 600-unit Lahore household wanting 4 hours of backup
These are the calculator’s own defaults, so you can reproduce every figure below by loading this page and reading the result box.
| Monthly electricity usage | 600 units |
|---|---|
| Backup hours needed | 4 hours |
| Recommended system | 5 kW |
|---|---|
| Storage for 4 h backup | ≈ 5 kWh lithium |
| Indicative on-grid cost | Rs 550,000 – Rs 700,000 |
| Battery modules, on top | ≈ Rs 225,000 |
Where these numbers come from
Cross-check: our 5 kW solar system price guide puts a complete turn-key on-grid 5 kW install at Rs 600,000 (July 2026) — inside the calculator’s Rs 550,000–700,000 band. Its module count, 9 × 585W, is the same count the panel-count math guide arrives at independently.
Those two guides do not agree on what those nine panels cost, and we are not going to average them into a number nobody published. The 5 kW build-up prices the array at Rs 175,000, about Rs 33 a watt; the panel-count guide prices it at Rs 228,762, nine modules at Rs 25,418 each, about Rs 43.45 a watt. Our own dated check on the Jinko Tiger Neo 585W records Rs 23,780–25,418 per panel at dealer rates (Rs 40.65–43.45/W) on 25 July 2026, which sides with the higher figure. Budget against Rs 40–43 a watt. The system-level total survives the disagreement because a Rs 50,000 swing on panels sits inside the Rs 110,000–140,000/kW band, but do not use the lower panel number when comparing quotes.
The battery line does not cross-check as cleanly, and we would rather say so. The same 5 kW guide prices a hybrid build with 5.12 kWh of lithium at Rs 1,000,000 all-in — roughly Rs 175,000 more than this calculator’s "on-grid mid-point plus Rs 45,000/kWh". The gap is the hybrid inverter and the heavier wiring, which the calculator does not price. Treat its battery figure as modules only.
What this calculator does not know
- Your roof. A 10 kW array is 17 × 585W modules over about 44 m² (475 sq ft) of unshaded roof per the panel-count guide; a 5 kW array is a little over half that. If the roof will not take it, the bill figure is academic.
- Your load shape. The battery figure divides your month by 720 hours, so it treats 3 a.m. and 8 p.m. as identical. If your evening is heavy — an AC on after sunset — size storage off your actual evening kWh instead. The load-shedding and UPS-mode sizing guide walks through that.
- Green-meter and DISCO application fees, which the 5 kW guide puts at about Rs 100,000 and the 10 kW guide at about Rs 150,000. They are not in the Rs 110,000–140,000/kW band.
- Whether you should be on-grid or hybrid at all. That is a separate decision — see the on-grid vs hybrid decision tree.
- Today’s price. The Rs/kW band is a July 2026 figure. Panel prices in Pakistan move weekly; re-check before you sign anything.
Frequently asked
How many kW solar system do I need for a 600-unit bill in Pakistan?
About 5 kW. At roughly 120 units per installed kW per month, 600 units divided by 120 gives 5 kW. Our 5 kW system guide records real-world output of 600–700 units a month for that size.
How many solar panels is a 5 kW system in Pakistan?
Nine 585W N-type TOPCon modules, giving 5.26 kW of DC array against a 5 kW inverter. A 10 kW system needs 17 of the same panel.
Should I still size my system for export under net billing?
No. Since February 2026 exported units earn roughly Rs 11 each while imported units cost Rs 50–65, so oversizing to export loses money. Size for what you can consume in daylight, then evaluate storage separately.
Does the calculator include installation, structure and the green meter?
The Rs 110,000–140,000 per kW band is a turn-key on-grid figure that covers panels, inverter, structure and wiring. It does not separately break out the DISCO green-meter and application fees, which run about Rs 100,000 on a 5 kW job.
Guides that explain the numbers
Itemised on-grid vs hybrid cost table
10 kW solar system price in PakistanHow many panels for a 5 kW or 10 kW systemOn-grid vs hybrid after net billingComplete cost of going solar in Lahore, all-inLoad-shedding schedules and UPS-mode sizingProducts this applies to
Run these next
What a stored unit is worth now that exporting it earns about Rs 11 — and how many years that takes to repay the bank.
Net metering vs net billing calculatorWhat a month of your generation was worth under 1:1 net metering, and what it is worth now — as a function of self-consumption.