# Energy & environment calculators

> Energy calculators for electricity use and cost, solar output and payback, battery runtime, EV charging cost and emissions estimates.

Page: https://calculators.geekmidst.com/categories/energy

- [Solar PV System Sizing Calculator](https://calculators.geekmidst.com/calculators/solar-pv-system-sizing-calculator.md): Size a solar PV system from your electricity use, local peak sun hours and system losses: kWp needed, number of panels, roof area and yearly output.
- [Solar Payback Calculator](https://calculators.geekmidst.com/calculators/solar-payback-calculator.md): Find how many years solar panels take to pay for themselves, with tariff rises, panel degradation and running costs, plus lifetime net savings.
- [Solar Self-Consumption Calculator](https://calculators.geekmidst.com/calculators/solar-self-consumption-calculator.md): From solar generation, export and household use, work out the self-consumption rate, self-sufficiency, grid imports and what your solar is worth.
- [Solar Inverter Sizing Calculator](https://calculators.geekmidst.com/calculators/solar-inverter-sizing-calculator.md): Size a solar inverter from array kWp and a DC/AC ratio, and check the maximum panels per string from cold-weather Voc and the inverter voltage limit.
- [Battery Backup Runtime Calculator](https://calculators.geekmidst.com/calculators/battery-backup-runtime-calculator.md): Estimate how long a battery, UPS or inverter backup will run a load from its Ah and voltage or kWh, usable depth of discharge and inverter efficiency.
- [Battery State of Charge Calculator](https://calculators.geekmidst.com/calculators/battery-state-of-charge-calculator.md): Track a battery’s state of charge by coulomb counting: starting SoC, current and time give the new SoC, remaining Ah and the time to full or empty.
- [Home Electricity Bill Calculator](https://calculators.geekmidst.com/calculators/home-electricity-bill-calculator.md): Estimate a home electricity bill from kWh used with up to three tariff blocks, a fixed or standing charge and tax, using the rates on your own bill.
- [Commercial Demand Charge Calculator](https://calculators.geekmidst.com/calculators/commercial-demand-charge-calculator.md): Work out a business electricity bill with demand charges: billed kW including any ratchet, energy charge, load factor and true cost per kWh.
- [Power Factor Correction Calculator](https://calculators.geekmidst.com/calculators/power-factor-correction-calculator.md): Find the capacitor kVAR and µF needed to raise power factor to a target, with the drop in kVA and line current, for single- or three-phase supplies.
- [Three-Phase Power Calculator](https://calculators.geekmidst.com/calculators/three-phase-power-calculator.md): Convert between three-phase current and power: kW, kVA and kVAR from line voltage, current and power factor, or the current a given kW load draws.
- [EV Charging Time Calculator](https://calculators.geekmidst.com/calculators/ev-charging-duration-calculator.md): Estimate how long an electric car takes to charge from its battery size, start and target charge, charger power, the car’s own limit and charging losses.
- [EV Charging Cost Calculator](https://calculators.geekmidst.com/calculators/ev-charging-cost-calculator.md): Work out what it costs to charge an electric car at your electricity price, including charging losses and session fees, plus the cost per 100 km.
- [EV Battery Range Calculator](https://calculators.geekmidst.com/calculators/ev-battery-range-calculator.md): Estimate an electric car’s remaining range from usable battery size, current charge, a reserve and its real consumption in kWh/100 km, Wh/km, Wh/mi or mi/kWh.
- [EV vs Petrol Running Cost Calculator](https://calculators.geekmidst.com/calculators/ev-vs-petrol-running-cost-calculator.md): Compare a year’s energy and maintenance cost of an electric car and a petrol car from your mileage, consumption and local electricity and fuel prices.
- [Diesel Generator Fuel Calculator](https://calculators.geekmidst.com/calculators/diesel-generator-fuel-calculator.md): Estimate a diesel generator’s fuel use and cost from its kW rating, load and the datasheet consumption, plus cost per kWh and hours per tank.
- [Wind Turbine Power Calculator](https://calculators.geekmidst.com/calculators/wind-turbine-power-estimate-calculator.md): Estimate wind turbine power from rotor diameter, wind speed, air density and power coefficient, with the wind’s total power and the Betz limit.
- [Heat Pump COP Calculator](https://calculators.geekmidst.com/calculators/heat-pump-cop-calculator.md): Work out a heat pump’s coefficient of performance from heat output and electrical input, compare it with the Carnot limit and estimate yearly running cost.
- [LED Retrofit Savings Calculator](https://calculators.geekmidst.com/calculators/led-retrofit-savings-calculator.md): Work out the yearly kWh and money saved by replacing lamps with LEDs, from wattages, hours of use and your electricity price, with payback in months.
- [Carbon Emissions Calculator](https://calculators.geekmidst.com/calculators/carbon-emissions-estimate-calculator.md): Estimate CO₂-equivalent emissions from electricity, petrol, diesel and natural gas use, multiplying each by an emission factor you enter from an official source.
- [Refrigerant GWP Calculator](https://calculators.geekmidst.com/calculators/refrigerant-gwp-equivalent-calculator.md): Convert a refrigerant charge in kg to tonnes of CO₂-equivalent using its global warming potential, with the yearly impact of a leak rate you enter.
- [Household Water Consumption Calculator](https://calculators.geekmidst.com/calculators/household-water-consumption-calculator.md): Estimate your home’s daily and yearly water use from showers, toilets, taps, laundry, dishwasher and garden, per person and as a yearly bill.
- [Rainwater Collection Calculator](https://calculators.geekmidst.com/calculators/rainwater-collection-calculator.md): Estimate how much rainwater a roof can collect from its area, the rainfall and a runoff coefficient, in litres, m³ and US gallons, plus days of supply.
- [Appliance Standby Energy Calculator](https://calculators.geekmidst.com/calculators/appliance-standby-energy-calculator.md): Work out how many kWh and how much money devices left on standby use in a year from their standby watts, the hours on standby and your tariff.
- [AC Annual Running Cost Calculator](https://calculators.geekmidst.com/calculators/ac-annual-running-cost-calculator.md): Estimate an air conditioner’s yearly electricity use and cost from its power draw, or from cooling capacity and EER, plus hours, days and tariff.
- [Heat Pump Payback Calculator](https://calculators.geekmidst.com/calculators/heat-pump-payback-calculator.md): Compare the yearly cost of heating with your current boiler and with a heat pump, using SCOP and your fuel and electricity prices, and see the payback period.
- [Solar Panel Tilt Angle Calculator](https://calculators.geekmidst.com/calculators/solar-panel-tilt-angle-calculator.md): Find a fixed solar panel tilt for your latitude, the seasonal summer and winter angles, and the tilt that faces the noon sun squarely in any month.
- [Inverter Efficiency Calculator](https://calculators.geekmidst.com/calculators/inverter-efficiency-calculator.md): Calculate an inverter’s conversion efficiency from its DC input and AC output power, the watts lost as heat and the energy lost over a year of operation.
- [Cable I²R Loss Calculator](https://calculators.geekmidst.com/calculators/cable-i2r-loss-calculator.md): Calculate the resistive power loss, voltage drop and yearly energy cost of a copper or aluminium cable from current, length and cross-section.
- [Power Transformer Efficiency Calculator](https://calculators.geekmidst.com/calculators/power-transformer-efficiency-calculator.md): Calculate a power transformer’s efficiency at any load and power factor from its kVA rating, no-load core loss and full-load copper loss.
- [Grid Export Revenue Calculator](https://calculators.geekmidst.com/calculators/grid-export-revenue-calculator.md): Estimate yearly income from solar power exported to the grid at your export tariff, plus the value of the solar you use yourself at your import rate.
- [Net Metering Estimate Calculator](https://calculators.geekmidst.com/calculators/net-metering-estimate-calculator.md): Estimate an electricity bill under net metering: consumption minus solar generation at your import rate, with any excess credited at your credit rate.
- [Home Insulation Savings Calculator](https://calculators.geekmidst.com/calculators/home-insulation-savings-calculator.md): Estimate the heating energy and money insulation saves from the area, U-values before and after, heating degree days, boiler efficiency and fuel price.
- [Waste Diversion Rate Calculator](https://calculators.geekmidst.com/calculators/waste-diversion-rate-calculator.md): Calculate the waste diversion rate: recycled, composted and reused waste as a share of all waste generated, with a choice on energy recovery.
- [Recycling Carbon Savings Calculator](https://calculators.geekmidst.com/calculators/recycling-carbon-savings-calculator.md): Estimate the greenhouse-gas emissions avoided by recycling aluminium, paper, plastics and glass, using the per-kg emission factors you choose.
- [Electricity Emissions Intensity Calculator](https://calculators.geekmidst.com/calculators/electricity-emissions-intensity-calculator.md): Work out the carbon intensity of an electricity mix in g CO₂e/kWh and lb/MWh from each source’s generation and emission factor, and your own footprint.
- [Tree Planting Carbon Estimate Calculator](https://calculators.geekmidst.com/calculators/tree-planting-carbon-estimate-calculator.md): Estimate the CO₂ a planting absorbs from the number of trees, survival rate, an average uptake per tree and years, and how many trees offset a yearly amount.
- [Biogas Output Calculator](https://calculators.geekmidst.com/calculators/biogas-output-calculator.md): Estimate daily biogas, methane, energy and electricity from an anaerobic digester’s feedstock, solids content and specific biogas yield per kg of volatile solids.
- [Solar Battery Storage Days Calculator](https://calculators.geekmidst.com/calculators/solar-battery-storage-days-calculator.md): Work out how many days a solar battery bank can run your daily load without sun, and the nominal capacity needed for a target number of days of autonomy.
- [Grid Outage Cost Calculator](https://calculators.geekmidst.com/calculators/grid-outage-cost-calculator.md): Estimate what a power cut costs a business in lost revenue, idle labour, backup running costs and one-off losses, per outage and over a year.