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.
-
Number Base ConverterConvert numbers between binary, octal, decimal, and hexadecimal instantly. Free online base converter with step-by-step decimal value shown.
-
Toothpaste CalculatorEstimate 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.
-
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.
-
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.
-
Torque Conversion CalculatorConvert torque between Newton-meters, pound-feet, pound-inches and kilogram-force meters instantly. Free, accurate torque unit converter with formula.
-
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.
-
Toilet Paper CalculatorFind out how many days your toilet paper supply will last based on rolls, sheets per roll, household size, and daily usage. Free TP calculator.
-
Watt-hour CalculatorCalculate energy in watt-hours (Wh) and kilowatt-hours (kWh) from power in watts and run time in hours. Free, instant Wh = P × t calculator.
-
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.
-
Volume Conversion CalculatorConvert volume between liters, milliliters, US gallons, quarts, pints, cups, and fluid ounces instantly. Uses US customary units for liquid measures.
-
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.
-
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.
-
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.
-
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.
-
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.
-
Rainwater Harvesting CalculatorCalculate how many gallons of rainwater you can harvest from your roof based on catchment area, rainfall depth, and runoff coefficient.
-
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.
-
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.
-
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.
-
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.
-
Water Tank Volume CalculatorCalculate water tank capacity in liters, US & UK gallons, and cubic meters. Works for cylindrical and rectangular tanks using simple dimensions.
-
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.
-
Length Conversion CalculatorConvert length between mm, cm, m, km, inches, feet, yards and miles. Fast, accurate metric-to-imperial length unit converter with formula.
-
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.
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.
