Electricity Bill Calculator — Tamil Nadu

Telescopically: each block of units bills at its own rate — first slab cheapest, climbing upward. 350 units doesn't bill all at the top rate; the first 100/200 bill at lower steps. The breakdown here shows exactly where your consumption lands, which is how to read your own bill.

Slab boundaries and (in some states) non-telescopic switches: Kerala famously re-prices ALL units at the top rate beyond 250. Even telescopic states bill marginal units at the highest slab — the last 50 units can cost double the first 50. The effective-rate line exposes it.

Your MARGINAL rate — the top slab you touch — because new consumption adds there and solar offsets there first. Using the average understates both costs and savings by 20–40% for most households; this calculator surfaces both numbers.

Indicative of recent tariff orders — DISCOMs revise annually, add fuel surcharges quarterly, and subsidies move with budgets. The structure (slabs, fixed, duty) is right; verify the current paise on your latest bill or the SERC order before fine-grained decisions.