This catch-all collection keeps your everyday reference tools in one place — convert Volumes and Temperatures instantly, look up any date on the Perpetual Calendar, time events with the Stopwatch or Online Alarm Clock, keep a running tally with the Counter, and convert Troy Weight for precious-metal calculations.
Browse the Most Popular list to see which tools others reach for most, or explore the Trending tab for newly added resources. Every tool is completely free, needs no sign-up, and works on any device.
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Volume Conversion CalculatorConvert volume between liters, milliliters, US gallons, quarts, pints, cups, and fluid ounces instantly. Uses US customary units for liquid measures.
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ppm to Grains per Gallon CalculatorConvert water hardness from ppm (mg/L) to grains per gallon (gpg) instantly. Uses gpg = ppm / 17.118 for accurate water softener sizing.
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Water Column to Pressure CalculatorConvert a water column height (feet or inches of water) into pressure in PSI, kPa and bar. Uses ftH2O x 0.4335 and inH2O x 0.03613.
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EC to TDS (ppm) CalculatorConvert electrical conductivity (EC in µS/cm or mS/cm) to TDS in ppm using a 0.5, 0.64, or 0.7 conversion factor. Free, instant water quality tool.
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Water Flow Rate Through a Hose CalculatorEstimate water flow rate through a hose from inner diameter, supply pressure and discharge coefficient. Get liters/min, GPM and exit velocity instantly.
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Heating & Cooling Load Calculator (Quick Manual J)Estimate your home's heating and cooling load in BTU/hr with this quick Manual J-style calculator. Based on US ACCA rule-of-thumb factors.
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Rainwater Harvesting CalculatorCalculate how many gallons of rainwater you can harvest from your roof based on catchment area, rainfall depth, and runoff coefficient.
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Air Conditioner BTU CalculatorFind the right air conditioner BTU for any room. Enter length, width, occupants, and sun exposure to size your AC unit instantly.
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LED vs Incandescent Bulb Savings CalculatorCalculate how much money and electricity you save each year by switching from incandescent bulbs to LEDs based on wattage, usage hours and energy price.
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Natural Gas Cost CalculatorEstimate your natural gas bill from therms used, price per therm, and any fixed monthly charge. Fast, free natural gas cost calculator.
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Propane Tank Usage CalculatorFind out how long your propane tank will last. Enter gallons of propane and your appliance's BTU/hour to get run time in hours and days.
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Water Tank Volume CalculatorCalculate water tank capacity in liters, US & UK gallons, and cubic meters. Works for cylindrical and rectangular tanks using simple dimensions.
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Torque Conversion CalculatorConvert torque between Newton-meters, pound-feet, pound-inches and kilogram-force meters instantly. Free, accurate torque unit converter with formula.
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Data Transfer Rate ConverterConvert data transfer rates between bps, Kbps, Mbps, Gbps, and B/s, KB/s, MB/s, GB/s instantly. Free online bandwidth and speed unit converter.
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Length Conversion CalculatorConvert length between mm, cm, m, km, inches, feet, yards and miles. Fast, accurate metric-to-imperial length unit converter with formula.
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Appliance Electricity Cost CalculatorCalculate how much an appliance costs to run. Enter watts, hours used, days and your kWh rate to get daily, monthly and yearly electricity cost.
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Monthly Electricity Bill EstimatorEstimate your monthly electricity bill from kWh usage, your rate per kWh, and any fixed service charge. See monthly and annual cost instantly.
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Flight CO₂ Emissions CalculatorEstimate the CO₂ emissions of any flight from distance, flight type and passenger count. See kg, tonnes and trees needed to offset your air travel.
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Pool Water Volume CalculatorCalculate swimming pool water volume in gallons and liters from length, width, and average depth in feet or meters. Fast, accurate, and free.
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Volts, Amps, Watts, Ohms CalculatorOhm's law calculator: enter any two of voltage, current, resistance or power and instantly compute the other two using V=IR, P=VI, P=I²R, P=V²/R.
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Car CO2 Emissions CalculatorEstimate the CO2 emissions and carbon footprint of your car trips from distance, fuel economy and fuel type (gasoline or diesel).
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Dew Point CalculatorCalculate dew point from air temperature and relative humidity using the Magnus-Tetens formula. Instant results in °C with dew point spread.
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Solar System Size CalculatorEstimate the solar PV system size (kW) you need from your monthly kWh use, peak sun hours and a system derate factor. Free, instant solar sizing.
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Electricity Usage Monthly Cost CalculatorEstimate the monthly electricity cost of any appliance from its wattage, daily hours of use, days per month, and your rate per kWh.
Frequently asked questions
What kinds of everyday tasks can I handle here?
You can convert volumes and temperatures instantly, look up any historical or future date on the Perpetual Calendar, time activities with the Stopwatch or set an Online Alarm Clock, keep a running count with the Counter, and convert Troy Weight for precious-metal calculations.
How accurate are the conversions and timings?
Conversion tools use internationally recognized factors (SI and US customary units). The Stopwatch and Alarm Clock rely on your device's clock for accuracy. For anything critical, double-check results against an authoritative source such as NIST or the relevant standards body before relying on them.
Do I need to create an account?
No — every utility tool here is completely free and requires no sign-up, login, or app download. Open any tool and start using it right away.
Do you record anything I enter or time?
No. All tools run entirely in your browser. We do not log, transmit, or store any values, dates, or timing data you use — everything stays private on your device.
Which utility tool is most popular?
The Most Popular list is ranked by real usage. The Temperature Conversion Calculator and Countdown Timer are consistently among the top tools. Open the Trending tab to see which utilities are gaining the most popularity right now.
