Enter an amount to see the result.
Short answer: In most Pakistani cities, 1 kW of panels makes about 4 to 4.7 units a day on a yearly average (Lahore 4.0, Karachi 4.65, Quetta 5.3), so 300 units a month needs about 2.5 kW in Lahore and 2.2 kW in Karachi. A 5 kW system makes about 19 to 23 units a day. New connections since 9 February 2026 get net billing, not net metering, and solar size cannot exceed your sanctioned load.
Key takeaways
- Size from your 12 month average: kW needed = yearly units divided by your city’s yearly output per kW (World Bank Global Solar Atlas data).
- Under NEPRA’s Prosumer Regulations 2026, imports are billed at the normal tariff and exports credited at the much lower national average energy purchase price.
- Net metering agreements signed before 9 February 2026 keep old billing until they expire.
- Up to 25 kW needs only DISCO approval and no NEPRA fee.
- Solar you use yourself in daytime saves the most.
How to use this solar system calculator
Enter your average monthly units, city, system type, panel size and the sanctioned load on your bill. You get system size, panels, roof area, monthly units, your bill before and after, and payback if you type your own quoted price. I built it because most calculators I checked use one flat figure for the whole country and hide their bill math. This one uses city data and the 2026 tariff from our electricity bill calculator.
How to size a solar system from your electricity bill
Average the last 12 months of units on your bill, then:
- Yearly units = average monthly units x 12.
- Find your city’s yearly output for 1 kW of panels in the table below, then take off 3% for grid outages and downtime.
- System size (kW) = yearly units divided by that output.
- Panels = system size x 1,000 divided by panel watts, rounded up.
- Check that the final kW is not more than your sanctioned load.
Solar output per kW in Pakistani cities
These figures are the long term specific yield (PVOUT) from the Global Solar Atlas, run by the World Bank Group and ESMAP with data from Solargis, read for one point in each city on 10 November 2026. Per Solargis, PVOUT already includes 3.5% soiling loss and 7.5% for inverter, cable, mismatch and shading losses, for panels at the best tilt facing south.
| City | Units per kW per day | Units per kW per month (after 3%) | Weakest month |
|---|---|---|---|
| Karachi | 4.65 | 137 | 103 (August) |
| Lahore | 4.02 | 118 | 90 (January) |
| Islamabad | 4.27 | 126 | 100 (January) |
| Rawalpindi | 4.32 | 127 | 101 (January) |
| Faisalabad | 4.10 | 121 | 92 (January) |
| Multan | 4.41 | 130 | 101 (January) |
| Peshawar | 4.12 | 121 | 97 (January) |
| Quetta | 5.30 | 156 | 137 (February) |
| Hyderabad | 4.80 | 142 | 123 (July) |
| Gujranwala | 4.03 | 119 | 88 (January) |
| Sialkot | 4.04 | 119 | 87 (January) |
| Bahawalpur | 4.52 | 133 | 106 (January) |
| Sukkur | 4.67 | 138 | 121 (December) |
| Abbottabad | 4.39 | 129 | 102 (February) |
Why the extra 3%? The atlas assumes the system never stops, but an on grid inverter shuts down when the grid goes off. NREL’s PVWatts manual uses 3% as its default availability loss. Raise it for shade, flat panels or an east or west roof. Peak sun hours (about 4.6 in Lahore and 5.4 in Karachi on flat ground, same atlas) are sunlight, not output, so do not multiply them by kW without losses.
Net metering vs net billing in 2026
The Prosumer Regulations 2026 (S.R.O. 251(I)/2026) took effect on 9 February 2026 and repealed the 2015 net metering regulations. As of 10 November 2026, NEPRA’s legal page lists three amendments: S.R.O. 547 (2 April), 709 (28 April) and 1330 (6 August 2026).
| Point | Net metering (2015 rules, old agreements) | Net billing (2026 rules, new connections) |
|---|---|---|
| How units are counted | Exported units are subtracted from imported units each 30 day cycle | Imports and exports are billed separately |
| Rate for your imports | Applicable tariff, on net units only | Applicable tariff, on every imported unit |
| Rate for your exports | Only surplus units, at the rate in your agreement | National average energy purchase price |
| Maximum size | Was 1.5 x sanctioned load (2018 amendment) | Not more than sanctioned load |
Under S.R.O. 547, a valid net metering agreement signed before 9 February 2026 keeps the old rate and mechanism until it expires, unless you make a change that raises the system’s maximum output. So think twice before adding panels to an old net metered system.
The buyback rate: the regulation credits exports at the “national average energy purchase price”, which NEPRA can revise. I could not find the current rupee figure in any NEPRA document, and news reports differ, so the calculator leaves it blank. Type the rate from your DISCO agreement; if blank, exports earn nothing in the estimate.
On grid vs hybrid vs off grid
- On grid: panels and a grid tied inverter, no battery. Cheapest, but it shuts down during load shedding for safety.
- Hybrid: hybrid inverter plus batteries, still on the grid. It runs fans and lights in outages and stores spare daytime units for the evening, which matters more now that exports pay little. Battery need = backup hours x load on battery (4 hours of 1 kW = 4 kWh usable).
- Off grid: no DISCO. You must size for the weakest month (January in most of Punjab and Khyber Pakhtunkhwa, August in Karachi), and the calculator does, plus batteries for every night.
Panels and inverter basics
Most home panels now are 72 cell (144 half cell) modules of about 550 to 600 W. A LONGi Hi-MO 6 measures 2,278 x 1,134 mm (about 2.58 square metres); the 640 to 665 W Hi-MO X10 is 2,382 x 1,134 mm (about 2.70). The calculator uses 2.58 per panel, editable, and shows panel footprint only; tilted rows need gaps.
For grid connection, the regulations require a UL 1741 compliant inverter, a manual disconnect switch with a visible break, and automatic protection against reconnecting to an unstable grid. Ask for the inverter’s certificate before you sign.
The Sales Tax Act (amended to 30 June 2026) charges 10% sales tax on solar panels (Eighth Schedule, serial 90); the Finance Act 2026 did not change it. It is already inside the quoted price.
Worked examples: 300, 500 and 800 units in Lahore and Karachi
Settings: net billing, 585 W panels, 3% extra loss, 50% of units used in daytime, filer, not protected, FCA and QTA zero, buyback blank, LESCO for Lahore and K-Electric for Karachi. The 500 and 800 unit homes (5 and 8 kW sanctioned load) are on the time of use tariff; as an example I assumed 20% of their units are peak hour units.
| Home | System | Units made per month | Bill before (Rs) | Imported / exported units | Bill after (Rs) | Saving per month (Rs) |
|---|---|---|---|---|---|---|
| Lahore, 300 units, 3 kW load | 5 panels, 2.93 kW, 12.9 m2 | 347 | 13,109 | 150 / 197 | 6,255 | 6,853 |
| Lahore, 500 units, 5 kW load | 8 panels, 4.68 kW, 20.6 m2 | 554 | 24,071 | 250 / 304 | 13,758 | 10,313 |
| Lahore, 800 units, 8 kW load | 12 panels, 7.02 kW, 31.0 m2 | 832 | 38,514 | 400 / 432 | 22,013 | 16,501 |
| Karachi, 300 units, 3 kW load | 4 panels, 2.34 kW, 10.3 m2 | 321 | 13,132 | 150 / 171 | 6,256 | 6,876 |
| Karachi, 500 units, 5 kW load | 7 panels, 4.10 kW, 18.1 m2 | 562 | 24,145 | 250 / 312 | 13,806 | 10,339 |
| Karachi, 800 units, 8 kW load | 10 panels, 5.85 kW, 25.8 m2 | 802 | 38,632 | 400 / 402 | 22,090 | 16,543 |
Lahore 300 units by hand. Before: 300 units x Rs 33.10 = Rs 9,930, fixed charges Rs 350 x 3 kW = Rs 1,050, FC surcharge 300 x 0.43 = Rs 129, then 18% GST on Rs 11,109 = Rs 1,999.62, total Rs 13,108.62. After, 150 night units from the grid: 150 x Rs 28.91 = Rs 4,336.50, fixed Rs 900, FC surcharge Rs 64.50, GST Rs 954.18, total Rs 6,255.18.
Each Rs 1 of buyback rate on those 197 exported units cuts about Rs 197 a month. Output also swings: about 264 units in January, 416 in April.
Under net billing, a unit you use yourself in daylight saves the full tariff, while a unit you export earns only the much lower buyback rate.
Payback: how to work it out from your own quote
Simple payback = price divided by yearly saving. Example only: suppose an installer quotes Rs 600,000 for the Lahore 4.68 kW system above. This is a made up round number to show the math, not a market price. Yearly saving is Rs 10,313 x 12 = Rs 123,758, so payback = 600,000 divided by 123,758 = 4.8 years, before any buyback credit. It ignores tariff changes, panel ageing, replacements and loan cost, so use it to compare quotes, not as a promise.
How to apply to your DISCO for net billing
Only a 3 phase 400 V or 11 kV consumer can apply. Steps and deadlines from regulations 3 and 4:
- Get the form (Schedule II) from your DISCO, free within 2 working days, and submit it. The DISCO checks it within 5 working days.
- Initial technical review within 15 working days. The DISCO cannot accept you if solar on your transformer has reached 80% of its rating.
- Sign the agreement within 7 working days, get the connection charge estimate within 7, and pay within 7.
- The DISCO installs the meter and connection within 15 working days of payment.
- Up to 25 kW the DISCO approves (S.R.O. 1330), no NEPRA fee (S.R.O. 709). Above 25 kW, NEPRA concurrence and Rs 1,000 per kW.
You pay for the meter and connection, and must start generating within 6 months of approval. Check your current bill first with the LESCO bill calculator, IESCO bill calculator, K-Electric bill calculator, MEPCO bill calculator or FESCO bill calculator, or browse all our free tools for Pakistan.
Scams and quality checks
- A promised zero bill under net billing is the old net metering pitch. Night units are still billed at full tariff.
- “Net metering guaranteed” for a new connection is false; new connections get net billing and can be refused if the transformer is full.
- A system bigger than your sanctioned load cannot be connected.
- Match the model and wattage on each panel’s back label with the datasheet.
- Get inverter model, UL 1741 compliance and warranty terms in writing, and compare quotes per watt for the same products.
My view: under net billing, size for daytime use first and add panels only if your buyback rate makes them pay. With a high evening load, a small battery may save more than extra panels. Try both in the calculator.
Frequently asked questions
How does a solar system calculator for Pakistan work?
It divides your yearly units by what 1 kW makes in your city in a year (Global Solar Atlas, 14 cities, minus 3%), rounds up to whole panels, and prices your bill before and after with the 2026 tariff.
How many solar panels do I need?
Panels = system kW x 1,000 divided by panel watts, rounded up. For 300 units a month: about 2.53 kW or 5 panels of 585 W in Lahore, 2.19 kW or 4 panels in Karachi.
How many units per day does a 5kW solar system produce?
On a yearly average, after 3% for outages: about 19.5 units a day in Lahore, 20.0 in Peshawar, 20.7 in Islamabad, 21.4 in Multan, 22.5 in Karachi and 25.7 in Quetta. Winter gives less, spring more.
Is net metering still available in Pakistan in 2026?
Not for new connections, which get net billing since 9 February 2026. Agreements signed before that date keep net metering until they expire, if you do not raise the system’s output.
What is the net billing buyback rate in 2026?
The regulation sets the basis (national average energy purchase price), not a fixed figure. For April to June 2026, NEPRA costed net billing exports at Rs 8.13 per unit and old net metering exports at Rs 25.32 (NEPRA SRO 1501(I)/2026). The calculator prefills Rs 8.13; use the rate on your own bill if it differs.
What is the maximum solar size I can install on net billing?
No more than your sanctioned load (regulation 3(2)). For more, first get a higher load from your DISCO.
How much roof space does a 5kW system need?
With 585 W panels and a 5 kW sanctioned load, 8 panels (4.68 kW) need about 20.6 square metres or 222 square feet, plus gaps between rows. Nine panels (5.27 kW) would exceed that load.
Can I put solar on a single phase connection?
Yes, off grid or hybrid without exporting. Net billing needs a 3 phase 400 V or 11 kV connection.
How many units does a 10 kW solar system produce a day?
On a yearly average, after 3% for outages, about 39 units a day in Lahore and 45 in Karachi, which is ten times the per kW figures above. Winter gives less and spring more.
This calculator gives an estimate based on Global Solar Atlas yields (read 10 November 2026), the NEPRA (Prosumer) Regulations 2026 as amended by S.R.O. 547, 709 and 1330 of 2026, and the CY 2026 tariff notified by S.R.O. 279(I)/2026, last checked 10 November 2026. It does not cover shading, wiring, structural design, panel ageing or battery losses; the buyback rate is your input. Your real bill is what your DISCO charges. Get a site survey and written quote from a qualified installer before you buy.