Methodology & Accuracy

1. Where the numbers come from

There is no "typical" or invented rate anywhere in the tool. Every slab rate, fixed charge, duty and surcharge is taken from a primary source:

• SERC tariff orders — the annual (or multi-year) tariff order issued by each State Electricity Regulatory Commission, which is the legal document that sets what a DISCOM may charge.
• DISCOM tariff schedules & FPPA circulars — the rate cards and the monthly/quarterly fuel-surcharge (FPPA/FPPCA/FAC) notifications that DISCOMs publish under those orders.
• Real consumer bills — actual printed bills, used both to confirm how the order is applied in practice and to verify our output (see section 3).

When a new order or FPPA circular is published, the corresponding rates in the tool are updated to match it. The current tariff figures reflect the 2025-26 orders, with the FPPA refreshed for July 2026.

2. How a tariff order becomes a calculation

A tariff order is prose and tables; a bill is arithmetic applied in a specific order. Our engine encodes that arithmetic exactly as the order specifies, rather than approximating it:

• Slab-wise rates — each slab rate applies only to the units that fall within its band, so a higher rate never applies to your whole consumption (see slab-wise rates). "Slab-benefit-lost" tariffs, where crossing a threshold re-rates every unit, are modelled where a DISCOM uses them.
• Fixed / demand charges — billed per kW of sanctioned load, per kVA of demand, or as a flat amount, following the category. For demand-billed categories the billed demand and any excess-demand penalty over the sanctioned/contract limit are computed.
• FPPA (fuel surcharge) — applied by whichever method the order specifies: a flat per-unit paise amount, or a percentage of the supply and demand charges (as under the UP MYT Regulations 2025). It can be a negative credit.
• Electricity duty and levies — the state duty is applied on the correct base and in the correct sequence (it is charged on the energy/fuel component, not on itself), because the ordering changes the final figure.
• kVAh billing — where a meter and tariff use apparent energy, energy is metered in kVAh and demand in kVA, so a poor power factor raises the bill directly instead of through a separate penalty.
• Time-of-Day, subsidies, net metering, LPSC and arrears — peak/off-peak blocks, eligible government subsidy, rooftop-solar net import, and late-payment surcharge are each applied where they apply.

3. Verified against real bills — to the paisa

The strongest test of a billing engine is not whether it looks right, but whether it reproduces an actual bill line for line. It does. Our engine reproduces real MVVNL (Madhyanchal Vidyut Vitran Nigam, a UPPCL DISCOM) bills to the paisa for the categories we have tested against printed bills, including:

• LMV-1 domestic and small-consumer bills — energy, fixed charge, fuel surcharge and electricity duty all reconcile with the printed total.
• LMV-17 / LMV-20 non-domestic and larger connections, including the demand-based and percentage-FPPA arithmetic.

When a real bill and our engine disagree, we treat it as a bug in our encoding of the tariff order and fix the logic — not as an acceptable rounding difference.

4. What we model — and what we don't yet

Being clear about the edges is part of being accurate. What the tool models well:

• Slab-wise and "slab-benefit-lost" energy slabs, fixed/demand charges, excess-demand penalty.
• FPPA by both per-unit and percentage methods, electricity duty, and common state levies.
• kVAh apparent-energy billing and power-factor effects.
• Time-of-Day peak/off-peak billing and rooftop-solar net metering.
• Eligible domestic government subsidies for the states that run them — Delhi (GNCTD), Punjab, Karnataka (Gruha Jyoti), Telangana and Tamil Nadu — applied to the domestic category when you opt in.

What we do not yet fully model, and where a real bill may differ:

• Some category-specific minimum charges — for example the LMV-2 minimum monthly charge is a known gap we have not yet reproduced exactly.
• Subsidy fine print — we model each subsidy conservatively as free energy on the eligible units (fixed charge, FPPA and duty still apply) and take Karnataka/Telangana's cap as a flat 200 units rather than the exact avg-consumption formula. States without a listed scheme have no subsidy applied, so a real bill there may be lower.
• Net metering and late-payment surcharge in the multi-DISCOM comparison table — these are excluded there for a like-for-like comparison, though the main calculator supports them.

Every result is a provisional estimate. Tariffs vary by sub-category, slab, city and sanction, so we always recommend verifying against your printed bill.

5. How often it's updated

Rates are refreshed as new tariff orders and FPPA circulars are published — typically once a year for the base tariff (following each SERC's order) and more often for the fuel surcharge, which moves monthly or quarterly. Corrections raised through real bills are applied to the underlying tariff data, so a fix for one consumer improves the estimate for everyone on that tariff.

6. Independence

TheDiscomBill is independent and not affiliated with any DISCOM, SERC or government body. Our estimate is guidance, not a legal ruling or an official bill. For a formal dispute, use your DISCOM's grievance forum; for a human read of a specific bill, our expert Bill Review service can help.

See it in action