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Why Did My Electricity Bill Suddenly Increase?
A bill that doubles without warning usually has a mundane explanation — and it's rarely "the meter is fast". Work through these eight causes in order: they're ranked from most to least common, and each comes with a concrete way to check it on your own bill.
1. Seasonal appliance load (the AC effect)
A single 1.5-ton AC draws roughly 1.2–1.6 kW. Run it 8 hours a night and that's ~300 extra units a month — often more than the rest of the house combined. Check: compare this month's units (not rupees) with the same month last year, not last month. Our electricity cost calculator converts your appliances into expected units.
2. Slab escalation — extra units cost more per unit
Indian domestic tariffs are slabbed: the price per unit steps up as monthly consumption rises. Crossing a slab boundary means the extra units are billed at the higher rate, so a 30% rise in usage can produce a 45% rise in the energy charge. Check: find your slab boundaries on your DISCOM's tariff page, then see which side of them your recent months fall.
3. Catch-up after estimated readings
If earlier bills carried a status like IDF/RDF or "average", you were billed on estimates. When an actual reading finally happens, all under-billed units land at once — and because of slab escalation they land at the highest rates. Check: the meter-status code and reading dates on the last 3–4 bills.
4. FPPA / fuel surcharge revision
The Fuel and Power Purchase Adjustment passes changes in your DISCOM's power-purchase cost through to you, and it's revised periodically (monthly or quarterly depending on the state). A new or increased FPPA line raises the bill with zero change in your usage. Check: compare the FPPA line across two bills with similar units.
5. Arrears and late-payment surcharge (LPSC)
A missed or partial payment carries forward as arrears and accrues LPSC (typically around 1.25–1.5% per month). The current bill then looks inflated even though current-month charges are normal. Check: the arrears line — current charges and arrears are always shown separately.
6. Tariff order revision
State regulators (SERCs) issue revised tariff schedules, usually effective April–June. Slab rates, fixed charges or duty may have changed since your last "normal" bill. Check: the tariff year printed on the bill against your DISCOM's current schedule.
7. Excess load penalty
If your recorded demand exceeds the sanctioned load, many DISCOMs bill the excess kW at a penal fixed-charge rate. Common after adding an AC or motor without upgrading the sanctioned load. Check: "recorded/billed demand" vs "sanctioned load" on the bill.
8. Meter fault or wrong multiplying factor
Genuinely faulty meters are the rarest cause, but a wrong MF after a meter replacement multiplies everything. Check: units = (current − previous) × MF by hand. If the printed units don't match, apply for a meter test (a small fee, refundable in many states if the meter is found faulty).
Still can't explain it?
Recalculate your bill from scratch with the free bill calculator — it itemises energy, fixed, FPPA and duty exactly as the tariff order specifies. If the printed total still doesn't match, upload the bill to our free expert Bill Review and a human will go through it line by line with you.
Frequently asked questions
Why is my electricity bill high even though usage is the same?
How do I check if my electricity meter is faulty?
What is FPPA and why does it change my bill?
Can I get a wrong electricity bill corrected?
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General guidance based on publicly available tariff orders and regulations; specifics vary by state, DISCOM and consumer category. Verify against your DISCOM's official schedule or your printed bill.