Environment

Quickly estimate how much you can save on yearly electricity and CO2 by replacing incandescent bulbs with LED or fluorescent lamps, based on wattage, hours of use, and the number of bulbs.

Estimate how much fuel money and CO2 you can save each year, and how many calories you'll burn, by replacing your car commute with a bicycle.

Estimate the annual electricity savings, CO2 reduction, and payback period when you replace an old appliance with an energy-efficient model, straight from the power consumption.

Estimate the electricity cost and CO2 emissions of running an AC in cooling mode from its power draw (W), hours, and days. You can also pick by room size.

Estimate the electricity cost and CO2 emissions of running your AC in heating mode, broken down per hour, day, and month.

Estimate the fuel cost and CO2 emissions of a kerosene fan heater from its kerosene use. Enter hourly consumption, hours per day, number of days, and the kerosene price to see the cost and CO2 for the period.

Estimate the gas cost and CO2 emissions of a gas fan heater from its consumption and running time. Works with city gas and LPG, and can convert from heating output (kW).

Enter your driving distance, fuel economy, fuel type, and fuel price to instantly estimate fuel consumption (L), fuel cost, and CO2 emissions. Supports gasoline and diesel, and also shows CO2 emitted per kilometer.

Enter your annual mileage and your fuel economy before and after to estimate how much you'll save on yearly fuel costs and how much CO2 you'll cut. See the impact of eco-driving or switching cars in real numbers.

Estimate the total CO2 emissions from your household and daily life based on electricity, gas, gasoline, kerosene, and water use. Also shows the equivalent number of trees needed to absorb it in a year.

Estimate the CO2 emissions and electricity cost of TVs, appliances and other devices from their power consumption (W) and usage time.

Estimate CO2 emissions from tap water use (m³ or L). Adjust the factor and see daily totals and a bathtub equivalent.

Compare aluminum cans and returnable bottles across any quantity to quickly estimate the difference in lifecycle CO2 emissions.

Estimate a wind turbine's power output (W/kW), swept area, and daily energy from rotor diameter, wind speed, and power coefficient. See the Betz limit too.

Estimate sunrise, sunset, solar noon and daylight length for any point on Earth from its latitude, longitude and date. Includes coordinate presets for major cities.

Just pick a major Japanese city such as Sapporo, Tokyo, Osaka, or Naha and choose a date to estimate that location's sunrise, sunset, solar noon, and length of daylight (possible sunshine hours) in Japan Standard Time.

Enter your starting point's temperature, pressure, and elevation plus the destination elevation, and estimate the destination's approximate temperature and pressure from the elevation difference. Great for planning hikes, drives, and outdoor trips.

Just enter the temperature and humidity to calculate the discomfort index (DI), a measure of how muggy it feels. Instantly see comfort levels such as comfortable, slightly hot, or hot and sweaty.

Estimate the apparent temperature from air temperature, wind speed, and humidity. Using Missenard's formula, see how much colder it feels as the wind picks up.

Estimate the distance to an earthquake's epicenter from the preliminary tremor duration (the P-wave to S-wave arrival gap) using Omori's formula.

Calculate the energy (J) an earthquake releases from its magnitude. Convert it to TNT and Hiroshima bombs to grasp the true scale.

Enter two magnitudes to calculate the ratio of energy released by each earthquake. Compare scales intuitively, such as about 32× per magnitude and 1,000× for two.

Estimate a tsunami's propagation speed (m/s and km/h) from ocean depth. See why deeper water means faster waves, and add a distance for an arrival-time estimate.

Calculate how much of a radioactive element remains and its remaining fraction from the initial amount, half-life, and elapsed time. You can also work backward to find the time needed to reach a given fraction.

Calculate the effective half-life — how long it actually takes for a radioactive substance in the body to halve — from its physical and biological half-lives.

Estimate the activity (Bq) left after radioactive decay from an initial becquerel value, nuclide, and elapsed time. Shows the remaining fraction and amount decayed too.

Pick a radionuclide and enter the becquerels of radioactive material ingested from food or water to estimate an adult's committed effective dose in mSv and µSv. Supports key nuclides such as cesium-137 and iodine-131.

Estimate the committed effective dose (mSv / µSv) from the becquerels and radionuclide of inhaled radioactive material, using ICRP reference inhalation dose coefficients.

Estimate cumulative external radiation dose (mSv) from a dose rate (µSv/h) plus exposure hours and days. Shows the annualized dose and a comparison with the 1 mSv/year public limit.

Multiply an absorbed dose in grays (Gy) by the radiation weighting factor to estimate the equivalent dose in sieverts (Sv). Pick a radiation type and see mSv and μSv at once.

Estimate how old a sample is from the remaining ratio of uranium-235 (half-life about 704 million years), or from the ratio of leftover parent to daughter isotopes.

Enter your usage (kWh), per-kWh energy rate, fixed monthly base charge, and any renewable-energy levy to instantly estimate a monthly electricity bill. It also shows the breakdown of energy charge, base charge, and levy, plus the effective all-in unit price per kWh. Handy for checking an estimate against your meter reading.