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Enter an earlier and a newer reading of the same meter and the number of days between them. You get the consumption for the period, the average per day, a projection for a month and a year, and the cost if you enter the price.

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The older reading, from your notes or the last bill.
Where do I find this?

Use the numbers before the decimal point (black digits). Red digits or digits after the comma are fractions.

The last bill shows the reading the supplier used.

Today's reading of the same meter.
Where do I find this?

Read the same register as before. Meters with two rates (day/night) have two registers: add both or calculate them separately.

Count the days from the first to the second reading.
Where do I find this?

Example: 1 March to 31 March is 30 days.

Price per kWh, per m³ or per gallon, from your bill.
Where do I find this?

For gas billed in kWh, convert the m³ first with the gas m³ to kWh calculator.

Only changes the symbol; no exchange rate is applied.

Result

Enter your values to see the result.

Consumption in the period
– units
Average per day
– units
Projected per month
– units
Projected per year
– units
Cost in the period
–
Projected cost per year
–

Want this tracked for you? UtilityControl logs your meters and costs automatically.

How it is calculated

  • Consumption = current reading − previous reading
  • Per day = consumption ÷ days; per year = per day × 365
  • Cost = consumption × price per unit

Example

Readings of 12,450 and 12,735 kWh 30 days apart: 285 kWh used, 9.5 kWh a day, about 3,468 kWh a year. At 0.30 per kWh the period cost 85.50.

What this estimate leaves out

A projection from one period ignores seasons: heating and air conditioning change the use a lot through the year. Read the meter regularly, ideally on the same day each month, to see the real pattern.

Written and reviewed by QLines, Cologne · Last reviewed

FAQ

Frequently Asked Questions

How do I calculate my usage from meter readings?

Subtract the previous reading from the current one. Divide by the number of days between them for the daily average.

Which numbers on the meter do I read?

The digits before the decimal point, from left to right. Ignore red digits and digits after the comma; they are fractions of a unit.

What if the new reading is lower than the old one?

The meter was probably replaced or rolled over to zero. Use the end reading of the old meter and the start reading of the new one separately.

How often should I read my meter?

Once a month on the same day is enough to spot changes early. Photos with the date make it easy to check a bill later.

More free calculators

Electricity Bill Calculator

Estimate your electricity bill from the kWh used, your price per kWh, a fixed fee and tax.

Water Bill Calculator

Estimate your water bill from the m³ used, the water and wastewater price, a fixed fee and tax.

Track your meters instead of calculating by hand

UtilityControl keeps your readings, usage and costs for every meter and location, and it starts free.

See UtilityControl Pricing