Everyday calculators

Dates, time, school, travel, conversions and handy tools. 31 calculators.

• Age calculatorExact age in years, months and days.
• Bandwidth calculatorDownload time from file size and speed, or the reverse.
• Base64 encoder and decoderEncode or decode Base64, privately in your browser.
• Date calculatorDays between dates, or a date plus or minus a span.
• Day of the week calculatorThe weekday of any date.
• Dice rollerRoll any dice, with a modifier.
• Dog age calculatorDog years to human years, the modern way.
• Driving carbon footprint calculatorCO₂ from driving a gasoline or diesel car.
• EV charging calculatorEV charging time and cost.
• EV vs gas cost calculatorElectric versus gasoline fuel cost per year.
• Fuel cost calculatorGas cost of a trip, split between riders.
• Gas mileage calculatorYour real MPG and L/100 km from a fill-up.
• GPA calculatorSemester and cumulative GPA from grades and credits.
• Grade calculatorWeighted grade, or the final exam score you need.
• Height calculatorPredicted adult height from the parents’ heights.
• Hours calculatorHours between two times, overnight included.
• IP subnet calculatorIPv4 network, broadcast, hosts and masks from CIDR.
• Password generatorStrong random passwords, generated privately.
• Reading and speaking time calculatorReading and speaking time for a word count.
• Roman numeral converterNumbers to Roman numerals and back.
• Screen size calculatorScreen width, height and pixel density.
• Sleep calculatorBedtimes or wake times that fit sleep cycles.
• Time calculatorAdd or subtract hours, minutes and seconds.
• Time card calculatorWeekly hours, overtime and pay from a time card.
• Time zone calculatorConvert a time between cities, with daylight saving.
• Tip calculatorTip, total and each person’s share.
• Tire size calculatorCompare two tire sizes and the speedometer change.
• TV viewing distance calculatorSeating distance for a TV, or TV size for a room.
• Typing speed calculatorTyping WPM and accuracy.
• Unit conversion calculatorConvert length, weight, volume, temperature and more.
• URL encoder and decoderPercent-encode or decode URLs and query values.