Residential electricity bills in India are slab-based, not flat-rate.
About this calculator
Residential electricity bills in India are slab-based, not flat-rate. Every additional unit moves into a higher price band, which is why air conditioner usage in April through July triples or quadruples the bill despite consumption only doubling. This calculator runs the exact slab math for the major state DISCOMs -- BESCOM in Karnataka, TANGEDCO in Tamil Nadu, APDISCOM in Andhra Pradesh, TGDISC in Telangana, MSEDCL in Maharashtra and BSES in Delhi -- and adds a generic India slab for states not explicitly listed.
The slab rates used are the published residential (LT-2) tariffs as of FY26-27, rounded to two decimals. Fixed charges (meter rental plus connection charge) vary between 40 and 200 per month depending on sanctioned load, so it is editable. Electricity duty and cess vary between 5% and 15% of the energy charge and is also editable. Exact numbers depend on your sanctioned load category, time-of-use rates if you have a smart meter, and any state subsidies.
The solar offset slot lets you enter the kWh generated by your rooftop panels in a given month. Under net-metering rules in most states, solar generation directly reduces billable units on a one-for-one basis up to a cap. A typical 3 kW rooftop installation produces 360-420 kWh per month, which is usually enough to zero out the bill for a small to mid-size household. See [[emergency-fund]] for budgeting the bill volatility and [[electricity-cost]] for per-appliance running cost.
Common uses
- Estimating the peak-summer bill for a 4-BHK in Bangalore at 800 kWh consumption
- Sizing a rooftop solar installation against current consumption and BESCOM tariffs
- Comparing the bill in Chennai versus Hyderabad for the same consumption
- Checking the marginal cost of running an AC 6 hours a day for a month
- Validating a BESCOM bill after a tariff revision
Frequently asked questions
How is an electricity bill calculated in India?
Residential consumption is billed in slabs. The first N units are priced at the cheapest rate, the next N at a higher rate, and so on. Your total energy charge is the sum of each slab
Why does my bill shoot up in summer?
Because you cross into higher slabs. Going from 200 to 500 units does not triple the energy charge -- it quadruples or quintuples it because the last 300 units are priced in a higher, marginal band. Air conditioners in April and May are the main culprit.
Can solar panels reduce my electricity bill?
Yes. A 3 kW rooftop solar installation produces 360-420 kWh per month on average, which can eliminate the energy charge portion of a typical household bill. You still pay the fixed charge and duty, so the bill does not go to zero. Under net-metering, excess generation is banked against future bills.
What is the electricity duty?
A state government cess on the energy charge, usually 5-15% depending on the state. It funds rural electrification and state utility losses. It is separate from GST (which does not apply to residential electricity) and appears as a line item on most bills.
Why does my DISCOM bill differ from this calculator?
DISCOMs add time-of-use differentials for smart meters, separate sanctioned-load fixed charges based on kW, and sometimes temporary tariff subsidies from the state government. This calculator uses the base residential tariff; actual bills can vary by 5-15% depending on these adjustments.