What "telescopic" billing means
TANGEDCO does not charge one flat rate for all the units you use. Instead, your consumption is split into bands (slabs), and each band has its own rate. Only the units that fall inside a given band are charged at that band's rate — not your entire usage.
This is different from how many people assume it works. A common mistake is looking up which slab your total usage falls into, then applying that single rate to every unit. That would overcharge you significantly. In telescopic billing, the lower slabs stay cheap (or free) no matter how much you use overall.
Worked example: 350 units, old tariff
Using the pre-May 2026 slab structure for consumption at or below 500 units:
| Band | Units charged | Rate | Amount |
|---|---|---|---|
| 1–100 | 100 | Free | ₹0 |
| 101–200 | 100 | ₹2.35 | ₹235 |
| 201–350 | 150 | ₹4.70 | ₹705 |
Total energy charge: ₹940 for 350 units — not 350 × ₹4.70 (which would wrongly total ₹1,645).
Why this matters when comparing tariffs
Because billing is telescopic, a change to just the "free units" threshold (like the new 200-units-free scheme) can meaningfully lower your bill even if every paid slab rate stays exactly the same — because more of your usage now falls into the free band before any paid rate kicks in.
What's not included in slab charges
- Fixed charges: a small charge based on your sanctioned load, applied regardless of usage
- Fuel Surcharge Adjustment (FSA): a variable per-unit charge that changes periodically based on fuel costs
- Any arrears or adjustments carried over from a previous billing cycle
These are why a slab calculator's estimate (including ours) will usually come in slightly lower than your actual bill.