Conversion

Convert milliseconds to exact decimal seconds and view a copy-ready hh:mm:ss.fff elapsed-time display.

Calculate exact chronological age by birth date and reference date, with years, months, days, next birthday, and optional totals.

Find your next half birthday, days until it, its weekday, and the equal-time midpoint from your birth date.

Turn questions correct into a percent and letter grade, or find how many right you need to pass or hit a target score.

Find the final exam score you need for your target class grade, or project your course grade from an expected final score.

Find the age gap between two people by birth dates, birth years, or current ages, with an optional compare-on date.

Check if any year is a leap year, see the rule path, and compare Gregorian and Julian results.

Convert pounds to ounces or pounds and ounces to total ounces with clear rounding and mixed-unit checks.

Convert ordinary weight ounces to decimal pounds and pounds plus ounces, including fractional ounce amounts.

Convert US liquid gallons to US liquid quarts. Enter a gallon amount for the exact quart equivalent.