Utilities

  • Fuel Economy Unit Converter (km/L ⇔ mpg ⇔ L/100km)
    Convert fuel economy between km/L, L/100km, L/km, US mpg and Imperial mpg, plus gal/100mi. Enter one value and get all eight units at once.
  • Watts to Amps Calculator
    Convert watts to amps for DC and single-phase AC circuits. Enter power, voltage and power factor to get current in amps instantly.
  • CCF to Therms Calculator
    Convert natural gas usage from CCF (hundred cubic feet) to therms using the standard 1.037 thermal factor. Free, instant, and adjustable.
  • Boiler Size Calculator
    Calculate the right boiler size for your home in BTU and kW based on floor area and climate zone. Free, fast heating output estimator.
  • Furnace Size Calculator
    Estimate the BTU furnace size you need by home square footage and climate zone. Quick heating capacity calculator for US/Canada homes.
  • Heat Loss Calculator
    Calculate heat loss through walls, roofs and windows from surface area, U-value and the inside–outside temperature difference. Get watts and daily kWh.
  • Appliance Wattage Calculator
    Calculate appliance power in watts from voltage and current. Enter volts and amps to get wattage and kilowatts instantly with this free tool.
  • Electricity Cost Calculator
    Calculate the electricity cost of any appliance from its wattage, hours of use, days, and price per kWh. Get daily and total cost plus energy used.
  • Generator Wattage Calculator
    Calculate the generator wattage you need by adding total running watts plus the largest starting surge. Free generator sizing calculator with headroom.
  • Single Usage Electricity Cost Calculator
    Calculate the electricity cost of running an appliance once. Enter power in watts, hours used, and your price per kWh to get the exact cost.
  • Hot Tub Cost Calculator
    Estimate the monthly, daily, and yearly cost of running your hot tub from heater power, daily run hours, and your electricity price per kWh.
  • Bath vs Shower Calculator
    Compare bath vs shower water use and cost. Enter your shower flow rate, time, tub volume and water price to see which is cheaper and greener.
  • Drip Faucet Water Waste Calculator
    Calculate how much water a dripping faucet wastes per day and per year in liters and gallons from drips per minute and drop volume.
  • Water Demand Calculator
    Estimate total daily water demand from population and per capita usage. Get results in L/day, m³/day, L/s and annual m³ for water supply planning.
  • Tap Water vs Bottled Water Calculator
    Compare the cost of bottled water vs tap water and see how much money you save by switching. Enter bottles, prices, and days to get instant savings.
  • Passive House Savings Calculator
    Estimate annual energy cost savings from building to passive house standard, based on floor area, energy use intensity, and energy price.
  • CO2 Emissions from Electrical Appliances Calculator
    Estimate monthly and yearly CO2 emissions from an appliance using its wattage, daily usage hours and your grid's emission factor (Japan utility presets included).
  • Amps to Watts Calculator
    Convert amps to watts for DC, AC single-phase and three-phase circuits. Enter current, voltage and power factor to get watts and kilowatts instantly.
  • Air Conditioner BTU Calculator
    Find the right air conditioner BTU size for any room. Enter area, occupants, and sun exposure to get a cooling capacity estimate in BTU and tons.
  • Air Changes per Hour Calculator
    Calculate air changes per hour (ACH) from airflow in CFM and room dimensions. Free ventilation calculator for HVAC, IAQ, and clean-room design.
  • Solar Panel System Size Calculator
    Calculate the solar panel system size (kW) you need from daily energy use, peak sun hours, and efficiency. Estimates the number of panels too.
  • Shower Cost Calculator
    Calculate the cost of a shower from flow rate, duration and your water and energy prices. See cost per shower, day and year, plus litres and kWh used.
  • Toilet Paper Calculator
    Find out how many days your toilet paper supply will last based on rolls, sheets per roll, household size, and daily usage. Free TP calculator.
  • Toothpaste Calculator
    Estimate how many days, weeks and months a tube of toothpaste will last based on tube size, household size, brushes per day and amount per use.

Categories