Inputs before answers
Bill units, city sunlight, system type, daytime use, tariffs, and market benchmarks all affect the result.
Assumptions stay visible
Planning values are explained so they can be replaced or challenged instead of mistaken for guaranteed facts.
Corrections are welcome
Send the exact page, statement, date, and a primary source when you find an error or outdated assumption.
What this website publishes
SolarCalculator.com.pk publishes Pakistan-focused solar planning calculators, buying guides, financing comparisons, product explainers, and city-specific planning pages. The tools turn user inputs and stated assumptions into estimates. The website does not provide a final engineering design, site survey, installer quotation, bank approval, DISCO approval, or performance guarantee.
How the core calculator works
The core methodology was last listed as reviewed on August 7, 2026. The calculation is intentionally simplified so a user can see the important inputs and test an installer quote. Current defaults are planning values and can be replaced by the user's own bill, units, city, system type, and usage pattern.
From bill to monthly units
If a user enters rupees instead of kWh, the model divides the bill amount by a blended tariff assumption. The current general default is Rs. 44/kWh and the K-Electric starting assumption is Rs. 48/kWh. Entering actual monthly units avoids this conversion uncertainty.
From units to system size
Monthly units are converted to average daily use, then divided by the selected city's peak-sun-hours assumption and a 75% planning performance ratio. The performance ratio allows for heat, wiring, inverter, mismatch, dust, and other operating losses; it is not a site-specific yield study.
Generation, direct use, and exports
Estimated generation uses system capacity, city peak-sun hours, 30 days, and the same performance ratio. The default on-grid and hybrid model treats 55% of generation as used at the property and values the remainder at the current Rs. 8.13/kWh export-credit assumption. Off-grid planning does not add an export credit.
Cost, savings, and payback
System cost begins with a per-kW planning benchmark for on-grid, hybrid, or off-grid equipment and applies a range rather than presenting one guaranteed quote. Directly used solar is valued against the retail-energy assumption; exported units are calculated separately. Simple payback divides estimated upfront cost by estimated annual savings and does not replace a full cash-flow or financing analysis.
Source and evidence standards
Regulatory and billing statements should be checked against official NEPRA, Ministry of Energy, DISCO, State Bank, or bank documents where those documents are available. Market-price references are treated as dated snapshots and are cross-checked rather than presented as guaranteed dealer prices. A source link does not mean that the source endorses this website.
- NEPRA Prosumer Regulations 2026 — primary source for the current prosumer and net-billing framework
- NEPRA calendar-year 2026 energy purchase price decision — source used for the current export-credit assumption
- Ministry of Energy net-metering FAQ — official background on application and metering requirements
Authorship and editorial policy
Content is currently published under the SolarCalculator.com.pk organization name. The website does not use an unnamed desk or a generic review label as proof of professional qualification. A person's name, professional title, qualification, or reviewer credit should be published only when that identity and role can be verified. Sources, assumptions, limitations, and the relevant review date are more useful than an unsupported authority claim.
Updates and corrections
A material regulation, tariff, export-credit, bank-product, market-price, or calculation change can make an older estimate inaccurate. Relevant pages should be reviewed when a primary source changes, and material edits should update the displayed review date. To report a problem, send the page URL, the exact statement or output, the date you saw it, and a supporting primary source when available. A supported correction should be updated or clarified rather than left as a silent conflict.
- Contact and request a correction — use the listed website contact channel
- Read the calculation disclaimer — understand what the estimates cannot guarantee
Safety and decision boundaries
Solar work can involve high-voltage DC, AC wiring, roof loading, earthing, surge protection, batteries, fire risk, and utility interconnection. Calculator outputs are an early planning aid. Confirm system design, equipment, structural suitability, electrical protection, installation scope, warranties, financing, and utility requirements with appropriately qualified providers before spending money or changing live equipment.