Energy & Utilities Calculators — Australia

What an appliance costs to run — per hour, day, month and year — from its wattage and your tariff.

Estimate a bill from your usage, including the standing charge that catches people out.

What it costs to charge an electric car at home, per charge and per hundred kilometres.

A gas bill from your usage — in megajoules, kilowatt-hours, therms or cubic metres — at your rate, plus the daily supply charge, with the usage converted into every unit and the effective price per kilowatt-hour that lets you compare gas with electricity.

Compare two electricity tariffs that trade a daily charge against a usage rate — the annual cost of each at your usage, the saving, and the usage at which the cheaper one changes.

A bill under a demand tariff — a charge on the highest power drawn in the month on top of the energy used — with the share the peak accounts for, the load factor that shows how peaky the site is, and the saving from shaving the peak.

What an internet plan is worth — the cost per megabit and per user, how long a large download takes, how many 4K streams it carries at once, and whether a data cap would run out.

What a mobile plan costs at your real usage — the base price plus any overage — the effective price per gigabyte, and the usage at which stepping up to a bigger plan becomes cheaper than paying for extra data.

The electricity that devices draw while switched off or idle — the phantom load — from how many there are and what they draw, with the yearly cost, the share of a household's usage and what a smart plug or a switch would save.

The carbon emissions of your electricity use from the kilowatt-hours on the bill and the intensity of your grid — per period, per year and per day — with the effect of a green-power share and what the figure equals in driving.

Your bill on a time-of-use tariff from how your usage splits across peak, shoulder and off-peak — what moving a share of the peak to off-peak saves, and whether the time-of-use tariff beats a flat rate at all.

How long a backup generator runs on a tank, what it burns per hour at your actual load, the fuel and cost for an outage of a given length, and how much fuel to keep on hand.

What your showers cost in water and in the energy to heat it — per shower and per year — and what a shorter shower or a low-flow head would save.

What a gas appliance costs to run from its rated input, the hours it runs and your gas price — per hour, per day and per year — with the emissions.

How long a battery will run a given load — from its amp-hours and voltage, how deeply it can safely be discharged, and the inverter’s efficiency — with the usable energy and the load that would last a full day.

The reactive power (kVAr) of capacitors needed to lift a site’s power factor from where it is to a target, with the apparent power and current before and after.

An estimate of your monthly mobile data from the hours you spend on video, music, social media, video calls, gaming and maps — and whether a plan’s allowance covers it.

What size generator a set of loads needs — the running watts they draw together, the surge when the largest motor starts, and a recommended rating with a safety margin.

How long a solar system takes to pay for itself, given what you self-consume rather than export.

What size battery your evening usage needs, and whether the arbitrage justifies the cost.

Roughly what capacity a room needs to heat or cool — and why oversizing is a real mistake.

Convert between R-value and U-value, and between the metric and imperial versions of each — with the heat flow through a square metre at a chosen temperature difference.