What this calculator does
The Meter Reading kWh Calculator tells you exactly how much electricity you have used between two readings of your meter. Utilities bill in kilowatt-hours (kWh), and every electricity meter records a cumulative total. By subtracting the previous reading from the current reading, and applying any meter multiplier, you get the energy consumed during that period.
How to use it
Read your meter now and enter that number as the Current meter reading. Enter the figure from your last bill or last manual reading as the Previous meter reading. Most domestic meters have a multiplier of 1, but some transformer-rated or commercial meters multiply the dial value (for example by 10, 40 or 100) — check the multiplier printed on the meter or your bill. Optionally add a price per kWh to estimate the cost of that usage.
The formula explained
The core equation is simply
$$\text{kWh used} = \left(\text{Current reading} - \text{Previous reading}\right) \times \text{multiplier}$$The reading difference is the raw number of register units consumed; the multiplier converts those register units into true kilowatt-hours. Cost is then the kWh figure multiplied by your unit rate.
Worked example
Suppose the meter now reads 5,420 and last month it read 5,000, with a multiplier of 1 and a rate of 0.30 per kWh. Usage = \((5{,}420 - 5{,}000) \times 1 = 420\) kWh. Cost = \(420 \times 0.30 = 126\). If the same meter had a multiplier of 10, usage would be \((420) \times 10 = 4{,}200\) kWh.
FAQ
What if my current reading is lower than the previous one? A meter can roll over after reaching its maximum (e.g. from 99999 back to 0). This calculator clamps negative differences to zero, so re-check your numbers or add the rollover amount manually.
What is the multiplier? It is a factor printed on the meter that scales the displayed register to actual kWh. Standard household meters use 1.
Does this work for gas or water? The same subtraction logic applies, but those meters measure volume (cubic metres or feet) and need a separate conversion to energy, so use a dedicated calculator for accurate gas billing.
