Estimate your monthly electricity bill from appliance usage and local rate.
An electricity bill has two parts that behave completely differently. The energy charge is consumption times rate and is the only part you can reduce by using less. The fixed standing charge covers metering and network access and is payable whether you use a kilowatt-hour or not, which is why a very frugal household sees a bill that seems stubbornly high. Tax and levies are then applied to the sum of both. Separating the two matters when you assess efficiency measures: if a third of your bill is fixed, halving your consumption does not halve your bill.
Electricity Bill
Bill = (kWh x rate + fixed charge) x (1 + tax%); daily average = bill / 30.44
Read the meter a week apart and multiply the difference by 4.35. That is more accurate than adding up appliance ratings, which always overestimates because nothing runs continuously.
Almost always a rate or standing-charge change, or a tariff rolling off a fixed period. Compare the unit rate on this bill against the last one before assuming a fault.