Net Billing Calculator
A home that imports 400 units and exports 300 units pays about Rs 11,284 in energy charges under net billing, against Rs 2,244 under old net metering, so net billing costs Rs 9,040 more that month. Net bill = imported units × slab rate − exported units × buyback rate of Rs 11.
How this result was calculated
Import: 400 units at the slab rate of Rs 36.46 = Rs 14,584. Export credit: 300 units × Rs 11 = Rs 3,300. Net billing energy charge = Rs 14,584 − Rs 3,300 = Rs 11,284; any credit above the import bill carries forward (Rs 0 here). Old net metering: 400 − 300 = 100 net units billed at Rs 22.44 = Rs 2,244. Difference = Rs 9,040. Fixed charges, FC surcharge, QTA, FPA and GST are added on top; use the bill calculator for the full bill.
Key facts
- Under net billing the imported units are billed at the normal slab rate (Rs 36.46 per unit for 400 units) and exported units are bought back at a flat rate, Rs 11 per unit by default, which is not yet confirmed on a NEPRA page.
- Under old net metering exported units cancelled imported units one for one, so a home importing 400 and exporting 300 units paid for only 100 units, at the lower slab those units reach (Rs 22.44).
- For the same 400 imported and 300 exported units, net billing charges Rs 11,284 and old net metering Rs 2,244: a difference of Rs 9,040 a month in energy charges alone.
- The net billing figure is energy charges only; the fixed charge per sanctioned kW, FC surcharge, QTA, FPA and GST are added on the real bill.
Formula
Net billing Rs = max(0, import × slab rate − export × buyback); old net metering Rs = max(0, import − export) × slab rate of the net units
- import = units taken from the grid in the month
- export = units sent to the grid in the month
- slab rate = unprotected (or protected) A-1 rate of the band the units reach
- buyback = flat Rs per exported unit under net billing
- Credit larger than the import bill carries forward to the next month
- Extra = net billing Rs − old net metering Rs, never below zero
Net metering calculator vs net billing: what changed in 2026?
Under the old net metering rules a bidirectional meter counted units in and units out, and the DISCO billed only the difference. Every exported unit cancelled an imported unit at the same slab rate, and if you exported more than you imported the spare units carried forward to the next month.
Under the NEPRA Prosumer Regulations notified in 2026, new solar connections are on net billing. Imports are billed at the normal slab rate of the band your imported units reach, and exports are bought at a flat buyback rate that is far below the slab rate. The two numbers are worked out separately and then set against each other, which is why the same month costs more under net billing.
Existing net-metering contracts are reported to stay on the old rules until they expire, but this is not yet confirmed on a NEPRA page. Ask your DISCO which regime your connection is on.
How is a net metering bill calculated in Pakistan?
Old rules: net units = imported − exported. If the result is positive, those net units are billed at the slab they reach, exactly like a home without solar. If the result is negative, the bill for energy is zero and the spare units are credited to the next month. For the default month above that gives 100 net units at Rs 22.44 = Rs 2,244.
New rules (net billing): imported units × slab rate gives the import bill, Rs 14,584 for 400 units here. Exported units × buyback rate gives the credit, Rs 3,300 for 300 units. Bill = import bill − credit = Rs 11,284. Because all imported units are charged at the slab their total reaches, exporting does not pull you into a lower slab any more.
What is the net billing rate for solar exports in Pakistan?
The calculator uses Rs 11 per exported unit, the figure most reported for the new rules. NEPRA has said the rate will be set from the national average power purchase price and revised over time, and the exact number has not been confirmed on a NEPRA page at the time of writing. Change the buyback field to the rate on your own bill or DISCO notice and the result updates.
Compare that with the import rate of Rs 36.46 per unit for 400 units: a unit you export is worth a fraction of a unit you import. Using your own solar power in the day, running the water pump, washing machine and AC while the sun is up, is worth more than exporting it.
Does excess export still carry forward?
Yes, in rupees rather than units. If the export credit for the month is larger than the import bill, the bill for energy is zero and the spare credit carries forward to the next month. The calculator shows the carry-forward amount instead of a negative bill. Under old net metering it was spare units that carried forward.
Worked examples
Import 400 units, export 300 units
Import bill 400 × Rs 36.46 = Rs 14,584; export credit 300 × Rs 11 = Rs 3,300; net billing charge Rs 11,284. Old net metering billed 100 net units at Rs 22.44 = Rs 2,244, so net billing costs Rs 9,040 more.
Export more than you import: 200 in, 500 out
Import bill Rs 5,782 at Rs 28.91 a unit; export credit Rs 5,500. Net billing still leaves Rs 282 to pay, because the credit per exported unit is lower than the cost per imported unit. Under old net metering the energy bill was Rs 0 and 300 units carried forward.
Credit larger than the import bill: 100 in, 300 out
Import bill Rs 2,244; export credit Rs 3,300. The energy charge is Rs 0 and Rs 1,056 of credit carries forward to next month. Under old net metering 200 spare units would have carried forward instead.
Heavy user: 600 in, 100 out
Import bill 600 × Rs 40.22 = Rs 24,132; export credit Rs 1,100; net billing charge Rs 23,032. Old net metering billed 500 units at Rs 38.95 = Rs 19,475. The extra is Rs 3,557, smaller than in the first example because the exports were small.
Protected consumer: 150 in, 100 out
A protected home is billed slab-wise at the protected rates, so the import bill is Rs 1,705. The export credit is Rs 1,100 and the net billing charge Rs 605, against Rs 527 for 50 net units under old net metering: Rs 78 more. The gap is small because protected rates are close to the buyback rate.
Energy charges for the same month under net billing and old net metering, unprotected A-1 tariff, buyback Rs 11 per unit
| Import | Export | Net billing | Old net metering | Extra under net billing |
|---|---|---|---|---|
| 100 units | 300 units | Rs 0 | Rs 0 | Rs 0 |
| 200 units | 500 units | Rs 282 | Rs 0 | Rs 282 |
| 300 units | 300 units | Rs 6,630 | Rs 0 | Rs 6,630 |
| 400 units | 300 units | Rs 11,284 | Rs 2,244 | Rs 9,040 |
| 500 units | 200 units | Rs 17,275 | Rs 9,930 | Rs 7,345 |
| 600 units | 100 units | Rs 23,032 | Rs 19,475 | Rs 3,557 |
| 800 units | 400 units | Rs 33,360 | Rs 14,584 | Rs 18,776 |
Common mistakes
- Subtracting exports from imports first. Under net billing all imported units are billed at the slab their total reaches; only the rupee credit is subtracted afterwards.
- Treating this as the full bill. The result is the energy charge only; the fixed charge, FC surcharge, QTA, FPA and GST come on top and are worked out by the bill calculator.
- Using the buyback rate as a fixed fact. It is an estimate until NEPRA or your DISCO publishes it; enter the rate from your own bill.
- Ticking protected when a single month in the last six went over the limit. One high month moves you to unprotected rates for every unit.
Safety: Only a DISCO-approved installer and a licensed electrician may connect a solar system for export, and the bidirectional meter is installed by the DISCO; never bypass the meter or back-feed the grid through a plug socket.
Frequently asked questions
What is the net billing calculation for a solar home?
Imported units × the slab rate they reach, minus exported units × the buyback rate. For 400 imported and 300 exported units that is Rs 14,584 − Rs 3,300 = Rs 11,284 in energy charges.
What is the solar export rate in Pakistan?
Reports put the net billing buyback rate at about Rs 11 per unit, but it is not yet confirmed on a NEPRA page. Under old net metering there was no export rate: each exported unit simply cancelled an imported one.
How much does a solar home save under net metering compared with net billing?
For the default month, old net metering charged Rs 2,244 and net billing charges Rs 11,284, so net metering saved Rs 9,040 more. Savings against having no solar at all are larger under both, because every unit you use in the day is not bought at all.
Is there a solar payback calculator for Pakistan?
Payback in years is the system price divided by the yearly saving. The saving is the bill you would have paid without solar minus the net billing bill, over twelve months. A payback tool that combines your quote with this calculator is planned; until then use this page for the monthly saving and your installer's quote for the price.
Does the buyback rate for solar change?
Yes. NEPRA has said the rate will track the national average power purchase price and can be revised. Enter the rate shown on your own bill in the buyback field; the default is only the figure most reported so far.
How are net metering units calculated on the bill?
The bidirectional meter has an import reading and an export reading. Under old net metering the DISCO billed import minus export; under net billing the two readings are priced separately and set against each other in rupees. This calculator accepts both readings and shows both results.
Can I still apply for net metering in 2026?
New connections under the Prosumer Regulations are on net billing. Whether existing net-metering agreements stay on the old rules until they expire is widely reported but not yet confirmed on a NEPRA page; check with your DISCO.
Sources
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