How to Calculate Sub-Meter Electricity Bills Fairly
In multi-tenant buildings and rented apartments with a single main DISCOM connection and private sub-meters, dividing the electricity bill causes frequent disputes. Because electricity tariffs in India are telescopic (higher slabs cost more per unit) and include fixed charges and electricity taxes, simply multiplying sub-meter units by the base slab rate causes the landlord to lose money, while applying the highest slab overcharges the tenant.
The Fair Proportional Blended Rate Method (Recommended)
Effective Unit Rate (₹/kWh) = Total DISCOM Bill Amount (₹) ÷ Total Billed Units (kWh)
Tenant Share (₹) = Tenant Sub-Meter Units (kWh) × Effective Unit Rate (₹/kWh)
Tenant Share (₹) = Tenant Sub-Meter Units (kWh) × Effective Unit Rate (₹/kWh)
This method automatically incorporates fixed demand charges, fuel surcharges (FAC/FPPCA), and government taxes proportionally according to exact consumption.
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Worked Sub-Meter Split Example
| Parameter | Value | Calculation Logic |
|---|---|---|
| Main DISCOM Bill | ₹3,200.00 | Total payable amount on the electricity board bill |
| Main Meter Total Units | 400 kWh | Total units consumed across entire property |
| Effective Blended Rate | ₹8.00 / unit | ₹3,200 ÷ 400 kWh = ₹8.00/kWh |
| Tenant Sub-Meter Units | 150 kWh (37.5%) | Sub-meter reading: Current - Previous |
| Tenant Payable Share | ₹1,200.00 | 150 kWh × ₹8.00 = ₹1,200 |
| Landlord / Owner Share | ₹2,000.00 | 250 kWh × ₹8.00 = ₹2,000 |