Science

Energy & Environment Calculators

Electricity, solar, EVs, carbon, water and sustainability. Free calculators with formulas and worked examples.

Electricity

Electricity Bill Calculator (Tiered Tariff)Enter your units and tariff to estimate the bill and the average price per kWh.LED Bulb Savings CalculatorEnter how many bulbs you replace and how long they are on to see your savings.Standby Power Cost Calculator (Phantom Load)Enter the standby power of your devices to see what idle electricity costs you.

Solar

Home Solar System Size Calculator (kW and Panels)Enter your electricity use and sun hours to estimate the solar system size you need.Solar Battery Size Calculator (Home Backup kWh)Enter the load and backup time to find the battery capacity you need.

Electric vehicles

EV Range Calculator (Battery, Efficiency and Weather)Enter battery size and consumption to estimate how far an EV will go.EV Charging Time CalculatorEnter battery size, charge levels and charger power to estimate charging time.E-Bike Range CalculatorEnter your battery size and riding style to estimate e-bike range.

Carbon footprint

Car CO₂ Emissions Calculator (Petrol, Diesel, Electric)Enter distance and fuel economy to estimate your car's CO₂ emissions.Electricity CO₂ Calculator (kWh to Carbon Emissions)Enter your electricity use and grid carbon intensity to get CO₂ emissions.

Heating and cooling

Heat Pump vs Gas Boiler Running Cost CalculatorEnter your yearly heat demand and prices to compare heat pump and boiler running costs.Heat Loss Calculator (U-Value, Walls and Windows)Enter areas and U-values to estimate how much heat a room or house loses.Heating Fuel Cost Comparison Calculator (per kWh of Heat)Enter fuel prices to see which heating option gives the cheapest heat.

Water

Rainwater Harvesting Calculator (Roof Collection)Enter roof area and rainfall to see how much water you can harvest.Shower Water and Energy Cost CalculatorEnter your shower time and flow rate to see how much water and energy your showers use.

Wind

Wind Turbine Power CalculatorEnter rotor size and wind speed to estimate the power a wind turbine produces.

Energy

Appliance Energy Cost CalculatorSee what a device costs to run from its wattage.Solar Panel Payback CalculatorDoes rooftop solar pay for itself, and how soon?

About these calculators

See what energy and resources really cost: electricity use and bills, solar and battery payback, heating and cooling, water use and emissions. Use your own tariffs and factors for the most accurate result; defaults are cited where we provide them.

Each calculator explains its formula, includes a worked example and lists its sources. Read how we check them on our editorial policy page, or browse all calculators.

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Please note: TheCalcTools gives general estimates for information and education. It is not financial, medical, legal or tax advice, and results should be checked before you make a decision. See our disclaimer and about page.