Electricity Bill (tariff slabs) Calculator

Estimate a whole electricity bill from meter units, tariff slabs, a fixed charge and tax. For one appliance use Energy Cost. Formula and worked example.

Energy used in the billing period (kWh) 480, first slab size (kWh) 100, first slab rate (per kWh) 4, second slab size (kWh) 200 gives

Total bill: 3,297 · Energy charge: 3,040

Estimate only. Not engineering or safety advice. Check the result against the applicable standard and the equipment data, and have a competent engineer review it before it is relied on. Terms of use.

Open in the calculator with these values

Formula

Energy charge = Σ (units in slab × slab rate) Bill = (Energy charge + Fixed charge) × (1 + Tax / 100)

Worked example

Input	Value
Energy used in the billing period (kWh)	480
First slab size (kWh)	100
First slab rate (per kWh)	4
Second slab size (kWh)	200
Second slab rate (per kWh)	6
Rate above both slabs (per kWh)	8
Fixed charge for the period	100
Tax or duty on the bill (%)	5

Slab 1: 100 kWh × 4 = 400
Slab 2: 200 kWh × 6 = 1,200
Above slabs: 180 kWh × 8 = 1,440
Energy charge = 3,040; with the fixed charge 100 = 3,140
Tax = 3,140 × 5 % = 157
Bill = 3,140 + 157 = 3,297

Typical values

Energy used in the billing period (kWh)	Total bill	Energy charge
50	315	200
100	525	400
200	1,155	1,000
300	1,785	1,600
480	3,297	3,040
800	5,985	5,600

Other inputs are the same as in the worked example above.

Assumptions

Units are billed in order: first slab, then second slab, then the rest at the third rate
Slab rates, fixed charge and tax are the values you enter from your tariff order
No demand charge, power-factor penalty, time-of-day rate or surcharge

Some tariffs apply one rate to all units (telescopic versus non-telescopic billing differ by utility). This calculator uses the telescopic method above; check your tariff order. It prices the whole bill from the units on your meter. To find what one appliance costs to run per day, month or year, use Appliance Running Cost (Energy and Cost).

Frequently asked questions

How is Electricity Bill (tariff slabs) calculated?

Energy charge = Σ (units in slab × slab rate); Bill = (Energy charge + Fixed charge) × (1 + Tax / 100). Worked example: Energy used in the billing period (kWh) 480, first slab size (kWh) 100, first slab rate (per kWh) 4, second slab size (kWh) 200 gives Total bill: 3,297 · Energy charge: 3,040.

What do I need to enter?

Enter energy used in the billing period (kWh), first slab size (kWh), first slab rate (per kWh), second slab size (kWh), second slab rate (per kWh), rate above both slabs (per kWh), fixed charge for the period and tax or duty on the bill (%).

Is this the cost of one appliance?

No. It prices the whole bill from the units on your meter. To find what one appliance costs to run, use the Energy Cost calculator with its power, hours and tariff.

How does slab billing work?

Units are billed in order: the first slab at the first rate, the second slab at the second rate, and the rest at the third rate. The fixed charge is added and tax is applied on the total. Some utilities bill differently, so check your tariff order.

How accurate are the results?

Every figure comes from the same tested engine as the Elecmetric calculators and is meant for estimating. Check design values against the standard and the equipment data you work to.

Next steps in a design: Energy Consumption kW to kWh
Formula guides: Energy and Cost Formulas: kWh and Payback Energy Meter Multiplier Formulas
Cost of one appliance: Energy Cost (one appliance)
All 78 conversions Electricity Bill from Tariff Slabs (fixed charge, tax) in Elecmetric