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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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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Days Between Dates CalculatorFind the exact number of days between two dates. Enter a start and end date to get the total days, signed difference, and weeks between them.
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Feet & Inches to Centimeters CalculatorConvert height in feet and inches to centimeters instantly. Enter feet and inches to get the exact cm and meters using the 2.54 conversion factor.
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Kg to Lbs CalculatorConvert kilograms to pounds instantly. Enter a weight in kg and get the exact pounds (and ounces) using the factor 1 kg = 2.2046226218 lbs.
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Cm to Inches CalculatorConvert centimeters to inches instantly. Enter a length in cm and get the exact inches using the 1 inch = 2.54 cm standard conversion.
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Cost Per kWh CalculatorFind your effective electricity rate per kWh by dividing your total monthly bill by the kilowatt-hours used. Fast, free energy cost calculator.
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Shoe Size ConverterConvert your foot length in cm to EU, US, and UK shoe sizes for men and women using Brannock-based linear sizing relations.
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Hex to RGB Color ConverterConvert any hex color code (#RRGGBB or #RGB) to its RGB values instantly. See the red, green and blue channels plus a live color swatch.
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Hourly to Yearly Pay CalculatorConvert your hourly wage to yearly, monthly, and weekly pay instantly. Enter your hourly rate and weekly hours to estimate your annual salary.
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Annual Appliance Running Cost CalculatorCalculate the yearly electricity cost of any appliance from its wattage, daily usage hours, and your price per kWh. Get annual, monthly, and daily costs.
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Gas Mileage (MPG) CalculatorCalculate your car's gas mileage in miles per gallon (MPG) from miles driven and gallons used. Also shows L/100km and km/L equivalents.
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GPM to LPM Flow Rate ConverterConvert flow rate from gallons per minute (GPM) to liters per minute (LPM) instantly. Also shows liters per hour and cubic meters per hour.
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Number Base ConverterConvert numbers between binary, octal, decimal, and hexadecimal instantly. Free online base converter with step-by-step decimal value shown.
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Roman Numeral ConverterConvert numbers to Roman numerals and Roman numerals back to numbers (1–3999). Free, instant converter using the standard subtractive notation.
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Appliance Run Time Battery CalculatorEstimate how long a battery will power an appliance from its Ah capacity, voltage, load watts and system efficiency. Free runtime calculator.
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Energy Cost Per Hour CalculatorCalculate the electricity cost per hour of any appliance from its wattage and your kWh rate. See hourly, daily, monthly and yearly running costs instantly.
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Cooking Measurement ConverterConvert cooking measurements between cups, tablespoons, teaspoons, fluid ounces and milliliters instantly with US customary volume equivalents.
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Days Until Date CalculatorCount the exact number of days until any future date with our free Days Until Date Calculator. Countdown to birthdays, holidays, deadlines and events.
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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.
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Daily Electricity Usage CalculatorCalculate daily, monthly and yearly electricity usage in kWh and cost from any appliance's wattage, hours of use, and your cost per kWh.
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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.
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.
