روف ٹاپ سولر کیلکولیٹر

1. اپنے بجلی کے بل سے اوسط ماہانہ یونٹ درج کریں، یا ماہانہ بل پر جا کر بل کی رقم درج کریں۔ فی یونٹ بجلی کی شرح بھی درج کریں۔
2. اپنی ریاست یا مرکز کے زیر انتظام علاقہ چنیں۔ اسی سے اوسط دھوپ اور سبسڈی کی شرح طے ہوتی ہے۔ اگر آپ کے انسٹالر نے پیداوار کا آنکڑا دیا ہے تو پیداوار کا اپنا آنکڑا استعمال کریں آن کریں۔
3. مربع فٹ میں سائے سے پاک چھت کا رقبہ درج کریں۔ تجویز کردہ سائز اتنا ہی رکھا جاتا ہے جتنا چھت پر لگ سکے، یا اپنا سائز آزمانے کے لیے خود منتخب کرنا ہے چنیں۔
4. فی کلوواٹ لگانے کی لاگت (سبسڈی سے پہلے) کا اپنے وینڈر کے کوٹیشن سے موازنہ کریں، اور اگر آپ اہل ہیں تو پی ایم سوریہ گھر سبسڈی لیں آن رہنے دیں۔
5. سسٹم کا سائز، سبسڈی، خالص لاگت، لاگت کی واپسی کا وقت اور 25 سال کی بچت دیکھیں۔ چارٹ دکھاتا ہے کہ آپ کی بچت کب آپ کی ادا کی گئی رقم سے آگے نکلتی ہے، اور ٹیبل میں ہر سال کا حساب ہے۔ سب کچھ آپ کے ٹائپ کرتے ہی بدل جاتا ہے۔

How this rooftop solar calculator sizes your system

A rooftop solar plant is sold by its peak capacity in kilowatts (kW). How many units it makes in a year depends on how much sun your area gets, so the calculator starts from your bill: it works out the units you use in a year and divides by what 1 kW makes in your state. The answer is rounded to the nearest 0.5 kW and then capped by your roof, because each kW needs about 10 sq m (roughly 108 sq ft) of shadow-free space according to MNRE's consumer guidance.

MNRE says 1 kW can make 4 to 5.5 units on a clear sunny day. Over a whole year, with cloudy and monsoon days, most of India averages less than that, so the state figures here range from 3.5 units a day in the north-east to 4.5 in Rajasthan and Ladakh. They are our estimates, not official numbers. If your installer or a neighbour's meter gives you a better figure, switch on "Use my own generation figure".

PM Surya Ghar subsidy

Under PM Surya Ghar: Muft Bijli Yojana, the central government pays a fixed subsidy (central financial assistance) to residential consumers who install a grid-connected plant through a registered vendor, using solar modules made in India from Indian cells. The rates below are from the scheme's guidelines as amended in 2025 and were unchanged when we checked in October 2026. Apply through pmsuryaghar.gov.in.

Special category means the north-eastern states, Himachal Pradesh, Uttarakhand, Jammu and Kashmir, Ladakh, Andaman and Nicobar Islands and Lakshadweep. Some states, Delhi among them, add a subsidy of their own on top; this calculator counts only the central amount. The scheme's own guide suggests 1 to 2 kW for homes using up to 150 units a month, 2 to 3 kW for 150 to 300 units, and above 3 kW beyond that.

Worked example

A family in Pune uses 300 units a month and pays about ₹7 a unit. With 4.2 units per kW per day, they need 3,600 ÷ 1,533 = 2.35 kW, so a 2.5 kW plant. It makes about 3,830 units a year.

• Cost at ₹60,000 per kW: ₹1,50,000
• Subsidy: 2 × ₹30,000 + 0.5 × ₹18,000 = ₹69,000
• Net cost: ₹81,000
• First-year saving: 3,600 units × ₹7 = ₹25,200

With the tariff rising 3% a year, the savings cover the ₹81,000 in a little over 3 years and add up to about ₹9.2 lakh over 25 years. The extra 230 or so units go to the grid under net metering. DISCOMs usually credit exported units at a lower rate than they charge, so the calculator leaves them out of the savings.

Before you sign

• Get two or three quotes from vendors registered on the portal. Prices depend on the panel brand, inverter, mounting structure and how high the roof is.
• Use your average rate per unit (total bill ÷ units), not just the top slab, or the savings will look bigger than they are.
• Panels slowly lose output over the years and an inverter may need replacing once, so treat the 25-year figure as an upper estimate.
• The CO₂ figure uses CEA's grid emission factor of 0.727 kg per unit for 2023-24. You can change it if CEA publishes a newer number.