Free Online Utility Calculators & Converters
Everyday tools for dates, times, grades, conversions, and more. Simple, fast, and free calculators for all your daily needs.
★ Most Popular Utility Tools
Age Calculator
Calculate your exact age in years, months, days, hours, and minutes from your birth date.
Date Calculator
Add or subtract days, weeks, months, or years from any date and find days between two dates.
Unit Converter
Convert between units of length, weight, volume, temperature, area, speed, and more.
GPA Calculator
Calculate your cumulative GPA and semester GPA with support for weighted and unweighted grades.
All Utility Calculators
Time Calculator
Add or subtract hours, minutes, and seconds to calculate elapsed time and time differences.
Hours Calculator
Calculate hours and minutes between two times for work schedules and time tracking.
Grade Calculator
Calculate your class grade and determine what scores you need on remaining assignments.
Concrete Calculator
Calculate cubic yards of concrete needed for slabs, footings, columns, and steps.
IP Subnet Calculator
Calculate IP subnet masks, network addresses, broadcast addresses, and host ranges.
Bra Size Calculator
Find your correct bra size using band and bust measurements with US, UK, and EU sizing.
Password Generator
Generate strong, random passwords with customizable length, symbols, and character types.
Dice Roller
Roll virtual dice for board games, RPGs, and gambling simulations with any number of sides.
Conversion Calculator
Convert between common units including metric to imperial for length, weight, and volume.
Fuel Cost Calculator
Calculate fuel costs for road trips based on distance, gas price, and vehicle MPG.
Voltage Drop Calculator
Calculate voltage drop in electrical circuits based on wire gauge, length, and current.
BTU Calculator
Calculate BTU requirements for heating and cooling a room based on size and insulation.
Square Footage Calculator
Calculate square footage of rooms, yards, and irregular shapes for flooring and landscaping.
Time Card Calculator
Calculate weekly work hours, overtime, and pay from time clock entries and punch times.
Time Zone Calculator
Convert times between world time zones and find the best meeting times across locations.
Gas Mileage Calculator
Calculate miles per gallon (MPG) for your vehicle based on distance traveled and fuel used.
Horsepower Calculator
Calculate engine horsepower from torque and RPM or using quarter-mile time and weight.
Electricity Calculator
Calculate electricity usage costs for appliances based on wattage, hours used, and kWh rates.
Ohms Law Calculator
Calculate voltage, current, resistance, and power using Ohm's Law for electrical circuits.
Resistor Calculator
Decode resistor color bands and calculate parallel and series resistance values.
Shoe Size Converter
Convert shoe sizes between US, UK, EU, and CM for men, women, and children's footwear.
Mileage Calculator
Calculate driving distance and mileage reimbursement for business travel expenses.
Speed Calculator
Calculate speed, distance, or time using the formula speed = distance / time.
Density Calculator
Calculate density, mass, or volume using the formula density = mass / volume for materials.
Mass Calculator
Calculate mass from density and volume or convert between mass units for science projects.
Weight Calculator
Convert between weight units including pounds, kilograms, ounces, grams, and stones.
Molarity Calculator
Calculate molar concentration, moles, or volume for chemistry solutions and dilutions.
Molecular Weight Calculator
Calculate the molecular weight of chemical compounds from their molecular formulas.
Roman Numeral Converter
Convert between Arabic numbers and Roman numerals for dates, outlines, and clock faces.
Golf Handicap Calculator
Calculate your golf handicap index using recent scores, course rating, and slope rating.
Tire Size Calculator
Compare tire sizes and calculate diameter, width, sidewall, circumference, and speedometer error.
Roofing Calculator
Calculate roofing squares, shingles, and materials needed based on roof dimensions and pitch.
Tile Calculator
Calculate how many tiles you need for floors or walls including waste and grout coverage.
Mulch Calculator
Calculate cubic yards of mulch needed for landscaping beds based on area and depth.
Gravel Calculator
Calculate tons or cubic yards of gravel, stone, or aggregate for driveways and landscaping.
Wind Chill Calculator
Calculate wind chill temperature based on actual temperature and wind speed for cold weather safety.
Heat Index Calculator
Calculate how hot it feels based on temperature and humidity to assess heat-related health risks.
Dew Point Calculator
Calculate dew point temperature from air temperature and relative humidity for weather and HVAC.
Bandwidth Calculator
Calculate download times, data transfer rates, and bandwidth requirements for files and streaming.
Time Duration Calculator
Calculate the duration between two times or dates in hours, minutes, days, and weeks.
Day Counter
Count the number of days between two dates including or excluding weekends and holidays.
Day of Week Calculator
Find what day of the week any date falls on for past, present, or future dates.
Stair Calculator
Calculate stair dimensions including rise, run, number of steps, and stringer length for building.
Paint Calculator
Calculate how many gallons of paint you need based on wall area, doors, windows, and coats.
Drywall Calculator
Calculate drywall sheets needed for walls and ceilings including waste allowance and joint compound.
Carpet Calculator
Calculate square yards of carpet needed for rooms including seams, pattern matching, and waste.
Lumber Calculator
Calculate board feet, linear feet, and lumber costs for construction and woodworking projects.
Week Number Calculator
Find the ISO week number for any date and convert between week numbers and calendar dates.
Countdown Calculator
Count down days, hours, and minutes until a special event, birthday, or deadline.
Split Bill Calculator
Split restaurant bills equally or by item among friends including tax and tip calculations.
Length Converter
Convert between inches, feet, yards, miles, centimeters, meters, and kilometers instantly.
Weight Converter
Convert between ounces, pounds, tons, grams, kilograms, and stones for cooking and shipping.
Temperature Converter
Convert between Fahrenheit, Celsius, and Kelvin for weather, cooking, and science.
Volume Converter
Convert between gallons, liters, cups, tablespoons, milliliters, and fluid ounces.
Area Converter
Convert between square feet, square meters, acres, hectares, and square yards.
Pressure Converter
Convert between PSI, bar, pascal, atmospheres, and mmHg for tires, weather, and science.
Energy Converter
Convert between joules, calories, BTU, kilowatt-hours, and electronvolts for physics.
Power Converter
Convert between watts, kilowatts, horsepower, and BTU/hour for electrical and mechanical power.
Speed Converter
Convert between mph, km/h, meters per second, knots, and Mach number for vehicles and wind.
About Our Utility Calculators
Date & Time Tools
Calculate your exact age with our age calculator, find the days between two dates with the date calculator, or compute time durations for any purpose.
Academic Tools
Track your academic performance with our GPA calculator for cumulative GPA, or use the grade calculator to determine what scores you need on finals.
Tool Categories
- • Date & Time: Age, date difference, countdown, duration
- • Academic: GPA, grade, final exam, test score
- • Converters: Length, weight, temperature, volume
- • Everyday: Tip calculator, split bill, fuel cost
- • Generators: Random numbers, passwords, UUIDs
- • Text Tools: Word count, character count, text analysis
Frequently Asked Questions
How do I calculate my exact age?▼
Use our age calculator by entering your birth date. It will show your exact age in years, months, days, hours, and even seconds, plus how many days until your next birthday.
How do I calculate days between two dates?▼
Our date calculator lets you find the exact number of days, weeks, and months between any two dates. You can also add or subtract days from a specific date.
How is GPA calculated?▼
GPA is calculated by multiplying each course grade by its credit hours, summing the results, and dividing by total credit hours. Our GPA calculator supports both standard (4.0) and weighted GPA scales.
What's a good tip percentage?▼
Standard tipping in the US is 15-20% for good service, with 18% being common. Use our tip calculator to quickly calculate tips and split bills among friends.