By DesiMetrics Editorial Team · Updated 1 September 2026
A telescopic electricity slab is a billing method where your electricity units are split into ranges (slabs), and each slab is charged at its own rate — only for the units that fall inside it. Your first 100 units might cost ₹3 each, but your next 100 units cost more, not your whole bill. It's called “telescopic” because the rate extends outward in sections, like a telescope, instead of jumping all at once.
What Does “Telescopic” Mean in Electricity Billing?
Most Indian electricity boards — including KSEB, BESCOM, TANGEDCO, MSEDCL and AEML — bill domestic consumers using slabs. A slab is simply a range of units, like 0–100 or 101–200.
In a telescopic tariff, each slab has its own rate, and that rate applies only to the units within that slab. If you use 150 units, the first 100 are billed at the first slab's rate, and only the remaining 50 units move up to the second slab's rate.
This is different from a flat-rate system, where every unit you use is billed at the same single rate no matter how much you consume.
Takeaway: Telescopic billing means each slab of units is priced on its own, not your entire consumption at one rate.
How Telescopic Slabs Are Calculated (With a Simple Example)
Here's the basic logic, step by step:
- 1Your total units consumed are compared against the slab boundaries set by your electricity board.
- 2Units inside the first slab are billed at the first slab's rate.
- 3Any units that spill into the next slab are billed at that slab's (usually higher) rate.
- 4This continues until all your units are accounted for.
- 5The slab charges are added together to get your total energy charge, before fixed charges and other add-ons.
Say a board uses these example rates for illustration (not real current tariffs): 0–100 units at ₹3.00/unit, 101–200 units at ₹4.50/unit, and 201–300 units at ₹6.00/unit.
If you use 150 units, you pay ₹3.00 for the first 100 units and ₹4.50 for the remaining 50 — not ₹4.50 for all 150.
Takeaway: You only pay the higher slab rate for the units that actually cross into that slab, never for your whole bill.
Telescopic vs Non-Telescopic Billing: What's the Difference?
Under non-telescopic billing, crossing into a higher slab can push your entire consumption to the new, higher rate — not just the extra units. This is sometimes called a “slab-jump” or “cliff” tariff structure.
| Telescopic Billing | Non-Telescopic Billing | |
|---|---|---|
| How units are priced | Each slab priced separately | Entire consumption priced at the slab you land in |
| Crossing a slab boundary | Only the extra units cost more | ALL units can cost more, retroactively |
| Bill jumps | Smooth, gradual increase | Can jump sharply for even 1 extra unit |
| Common in India | Yes, used by most domestic tariffs | Less common, sometimes used for other categories |
| Consumer-friendliness | Generally seen as fairer | Can penalize small increases in usage |
Takeaway: Telescopic billing is gentler — you're never penalized for your entire bill just because you used a few extra units.
Why Do Electricity Boards Use Telescopic Slabs?
Telescopic slabs are designed to keep electricity affordable for low-usage households while asking heavier users to pay more per unit for their extra consumption. This supports:
- Basic affordability — the first slab, covering essential usage like lighting and fans, stays cheap.
- Fair cost recovery — heavier consumers, who put more strain on generation and infrastructure, pay a higher marginal rate.
- Predictable bill growth — because only extra units get pricier, bills rise smoothly instead of spiking suddenly.
In short, a telescopic tariff is really a stated affordability policy: low usage is subsidized, high usage cross-subsidizes it.
Takeaway: Telescopic slabs balance affordability for small users against fair cost recovery from bigger users.
Real Example: Calculating a Bill Using Telescopic Slabs
Let's fully work through a consumer using 260 units in a month, using the same illustrative example rates as before:
| Slab | Units in Slab | Rate/Unit (example) | Slab Charge |
|---|---|---|---|
| 0–100 units | 100 | ₹3.00 | ₹300.00 |
| 101–200 units | 100 | ₹4.50 | ₹450.00 |
| 201–300 units | 60 | ₹6.00 | ₹360.00 |
| Total (260 units) | ₹1110.00 |
Notice that only the final 60 units (201–260) are billed at the top rate of ₹6.00. The first 200 units still get their original, cheaper slab rates. This is the core mechanic of telescopic billing in action.
Your actual bill also includes fixed charges, electricity duty, and sometimes a fuel cost adjustment — the slab calculation above covers only the energy charge portion. For a full breakdown priced on your own DISCOM, try our electricity bill calculators by state.
Takeaway: A telescopic bill is really several smaller bills — one per slab — added together.
Which States/Boards Use Telescopic Billing?
Telescopic billing is the norm for domestic consumers across most Indian states, though the exact number of slabs, slab widths, and rates differ significantly board to board. Boards like KSEB (Kerala), BESCOM (Karnataka), TANGEDCO (Tamil Nadu), MSEDCL (Maharashtra) and AEML (Mumbai) all use some form of telescopic slab structure for household connections.
Because tariffs are revised periodically and vary by connection type (rural/urban, single-phase/three-phase, subsidized categories, and so on), the number of slabs and their rates are not the same everywhere — and they change over time. See real, source-cited rates on our BESCOM and other state unit-price pages.
Always check your own board's current, official tariff order rather than relying on a generic figure, since rates and slab boundaries are revised periodically.
Takeaway: Telescopic billing is widespread in India, but the specific slabs and rates are set individually by each state board and change over time.
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Frequently asked questions
Is my state's electricity billing telescopic or non-telescopic?
Most Indian states use telescopic billing for domestic (household) connections, but the exact structure varies by board and connection category. Check your latest electricity bill or your board’s official tariff order to confirm which applies to you.
Does telescopic billing mean I pay less overall?
Not necessarily less — it means you’re never charged the higher rate for units you used before crossing into that slab. Non-telescopic billing can sometimes cost more overall because it can apply the higher rate to your entire consumption.
Why did my bill jump a lot even though I used only slightly more units?
Under telescopic billing, a small usage increase alone shouldn’t cause a big jump, since only the extra units are billed higher. A sharp jump is more likely due to a fixed-charge change, seasonal tariff revision, or a non-telescopic category — check your bill’s rate breakdown.
Are fixed charges also telescopic?
No. Fixed charges (also called demand charges) are usually a flat amount based on your sanctioned load or connection type, separate from the telescopic energy charge slabs.
Do commercial and industrial connections use telescopic billing too?
Some do, but many commercial and industrial tariffs use different structures, including flat rates or demand-based billing. Telescopic slabs are most commonly associated with domestic household tariffs.
How often do telescopic slab rates change?
Slab rates and boundaries are revised periodically by each state's electricity regulatory commission, often once a year or after a tariff petition is approved. Always refer to your board's latest published tariff order for current rates.
Sources: state Electricity Regulatory Commission (SERC) tariff orders for each DISCOM. Rates and slab boundaries vary by board and change periodically — always confirm against your board's latest official tariff order.