Indian Electricity Calculator

This calculator does one job precisely: it turns two meter readings and one agreed rate into a payable amount. That is exactly what a tenant and landlord need when a sub-meter and a fixed per-unit rate are written into the rent agreement.

What it is not is a replica of your DISCOM bill. Almost every state distribution company bills domestic supply on telescopic slabs: the first block of units is charged at a low rate, the next block higher, and so on. You are not moved to one expensive rate when you cross a threshold — each block keeps its own rate, and only the units above the threshold cost more.

The consequence is that your effective rate per unit is not a constant. It climbs with consumption. Using an illustrative three-slab structure of ₹4.50, ₹7.00 and ₹9.00 with 100-unit blocks:

The effective rate moves from ₹4.50 to ₹7.70 across that range — on the same tariff, for the same household. Doubling consumption from 100 to 200 units does not double the bill, it multiplies it by about 2.6. So a flat rate that matched your bill last month can be wrong this month simply because you ran the air conditioner more.

Those exact rates and block sizes are illustrative. Your state's commission publishes the real ones and revises them, typically each financial year, so check your own tariff order or the slab table printed on your bill rather than relying on any number here.

This is the arithmetic behind a great many tenant-landlord arguments, and it catches people who are being completely honest with each other.

Take a building with three tenants who each consume 120 units in a month. Bill each of them separately against the slab table above and each owes ₹590, totalling ₹1,770. But the main meter records 360 units as a single connection, and 360 units on the same tariff costs ₹2,590 — because that consumption reaches into the ₹9.00 block, which no individual tenant reached on their own.

Someone has to absorb that ₹820 gap. Slabs are calculated per connection, not per person, so shared supply is inherently billed at a higher effective rate than the same usage split across separate connections. Neither party is cheating; the tariff structure simply does not decompose.

There are two more reasons the sums drift apart. Common load — staircase and corridor lights, the water pump, a lift, the motor for an overhead tank — is usually wired to the main meter and appears on nobody's sub-meter. And sub-meters do not capture line losses in the cabling between the main board and each unit.

The practical fix is to agree the method in writing before the first bill, not after a dispute: derive the flat per-unit rate by dividing the total main-meter bill by total units recorded (which distributes the slab effect proportionally), then decide separately how common-area load is shared — usually equally per unit, or by floor area. If you are splitting several shared heads and not just electricity, the shared expense split calculator handles the whole set at once.

The calculator rejects a current reading lower than the previous one, and requires whole numbers, because both usually indicate a misread rather than negative consumption. A few situations produce that legitimately:

The meter was replaced.A new meter starts near zero, so the old closing reading and the new opening reading are not comparable. Bill the two periods separately — old meter's final reading minus its last billed reading, plus the new meter's reading from zero.

The meter rolled over. Older mechanical meters with five digits reset after 99999. Units consumed then equal (100000 − previous) + current.

You read a different display. Digital meters cycle through several values — cumulative kWh, instantaneous kW load, maximum demand, power factor, sometimes separate peak and off-peak registers. Only the cumulative kWh reading belongs in these fields. Note which display index it is and use the same one every month.

Beyond that, the habit that prevents most disputes is dull but effective: photograph the meter on a fixed date each month with the reading legible, and record the closing reading at move-in and move-out in the agreement itself. When a tenant changes mid-cycle, the move-in / move-out meter settlement calculator handles the same reading maths while also accounting for an amount already paid or held as deposit.

A flat sub-meter rate is convenient and, when derived from the actual bill, fair to both sides. It stops being fair when it is set once and never revisited: tariffs are revised, fuel surcharges move, and a rate agreed two years ago may now be well above or below what the landlord actually pays.

A reasonable arrangement states the rate in the agreement, notes that it will be reviewed when the DISCOM revises its tariff, and gives the tenant the right to see the main bill for any month they are being charged for. Transparency costs the landlord nothing when the rate is honest.

One legal point worth knowing rather than guessing at: the resale of electricity by a landlord above the applicable tariff is restricted in many jurisdictions, and the rules differ by state. If a proposed rate looks well above the DISCOM's own slab rates, it is worth checking your state's regulations or asking the distribution company directly.

This tool computes units × rate in your browser from the values you enter — nothing is uploaded and no account is needed. It is a reference for verifying a settlement, not a substitute for your official bill, and it does not model slabs, fixed charges, duty, or subsidies. For anything with legal or financial consequence, the DISCOM bill and your tenancy agreement are the documents that count.