Everyday calculators
Daily math should not need a spreadsheet. Split a bill, size a TV, convert a cup of flour, or pick a bedtime with the formula in view.
16 free calculators in this collection. Open any tool for instant results, the formula, and FAQs.
Rent Increase Calculator
Turn a rent hike into new monthly rent, percent increase, and extra cost per year. Enter a percent or a dollar increase for tenants and landlords.
Open calculator →TV Size / Viewing Distance Calculator
Convert seating distance to a recommended 4K TV diagonal, or a TV size to a viewing distance. Uses ~30° cinematic angle rules of thumb.
Open calculator →Tire Size Difference Calculator
Compare two tire sizes (width / aspect / rim). See diameter, circumference, plus speedometer error if you change overall height.
Open calculator →Gas Trip Cost Calculator
Estimate fuel cost for a road trip from miles, MPG, and price per gallon. Optional round trip and split among passengers.
Open calculator →Sleep Calculator
Find bedtimes from a wake-up time, or wake times from a bedtime, using 90-minute sleep cycles plus time to fall asleep.
Open calculator →Caffeine Half-Life Calculator
See how much caffeine is still in your system and when it will wear down to a quarter-cup or nearly gone. Default adult half-life is 5 hours.
Open calculator →Dog Age Calculator
Convert dog years to human years with a size-aware chart: 15 the first year, 9 the second, then about 4–7 human years per calendar year.
Open calculator →Cat Age Calculator
Convert cat years to human years: about 15 at one year, 24 at two years, then roughly four human years per calendar year.
Open calculator →Cooking Measurement Converter
Convert cups, tablespoons, teaspoons, fluid ounces, ml, grams, ounces, and pounds. Optional ingredient density for volume-to-weight.
Open calculator →Female Delusion Calculator
Estimate what share of U.S. men match selected age, height, income, race, and relationship filters. A demographic dating-market illustration—not a judgment.
Open calculator →Tattoo Price Calculator
Estimate tattoo cost from size, style, color, placement, and artist hourly rate. Includes shop minimum, sessions, and a 20% tip.
Open calculator →Age Calculator
Calculate age in years, months, days, and total days.
Open calculator →Date Difference Calculator
Find the number of days, weeks, and hours between two dates.
Open calculator →Tip Calculator
Calculate a tip, total bill, and amount per person.
Open calculator →Discount Calculator
Find a sale price and savings after a percentage discount.
Open calculator →Sales Tax Calculator
Calculate sales tax and the final price for any local tax rate.
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