Utility Bill Calculator

Resource

Previous reading

Current reading

Tariff per unit

Previous night reading

Two-rate meters only.

Current night reading

Night tariff

Occupants

Days in the period

Result

Amount due$1,820.00
Consumption280
UnitkWh
Per day9.333
Per person606.67
Night-rate sharesingle-rate meter

The difference in readings, times the tariff

Works out consumption and cost from meter readings for electricity, water, gas or heating, including two-rate meters, and breaks the result down per day and per person.

The arithmetic on a bill is simple: current reading minus previous, multiplied by the tariff. It gets awkward with a two-rate meter, where day and night are counted separately, and with the habit of remembering readings 'roughly'.

The breakdown is more useful than the total. Daily consumption tells you whether this month is normal for your household, and the cost per person answers the question of who is using disproportionately much.

What this calculator shows

Consumption for the period in kilowatt-hours, cubic metres or gigacalories
The amount due, including the night rate
Average daily use and the cost split per occupant

What to keep in mind

Meters do not run backwards: if the current reading is below the previous one the calculator refuses rather than returning negative consumption.
Each resource keeps its own tariff — the selector only changes the unit the result is labelled with.

FAQs

How do I calculate a bill from a meter?

Subtract the previous reading from the current one and multiply by the tariff. A two-rate meter needs the same sum twice, once for each zone.

Is a two-rate meter worth it?

If more than a third of your consumption falls at night, yes. On an ordinary daytime routine the saving is eaten by the higher day rate.

How much electricity does a household use?

A flat without an electric hob or air conditioning usually lands between 150 and 300 kWh a month. An electric hob adds 100 to 150, a water heater up to 300.

What if I submitted a wrong reading?

Submit the correct one next month: consumption is calculated from the difference and evens itself out. A backdated correction is something the utility does on request.

Worked example

A month of electricity

Input: 12,000 to 12,280, tariff 6.5, three occupants

Output: 280 kWh, 1,820 in cost, 9.3 kWh a day

Note: 280 kilowatt-hours for three people is ordinary for a flat with no electric hob and no air conditioning. Past 400 usually means a water heater, underfloor heating or something running around the clock.

Useful links

All tools in Home & Utilities

Utility Bill Calculator

Result

Related tools

Water Consumption Calculator

Heating Power Calculator

Firewood Calculator

Useful links