Time & Date Calculators
Free age, date, GPA, grade, and time zone tools for students and professionals
11 calculators that handle leap years, DST transitions, weighted GPAs, and live countdowns - built for accuracy across calendars and time zones.
Age Calculator
Years, months, days breakdown and next birthday
Date Calculator
Days/months/years between dates
Time Calculator
Add/subtract time and durations
GPA Calculator
Term and cumulative GPA
Grade Calculator
Final grade based on weights
Countdown Timer
Live countdown to any future date or event
Date Add/Subtract Calculator
Add or subtract days, months, and years from any date
Work Hours Calculator
Calculate work hours and earnings by period
Time Zone Converter
Convert time between any two time zones
Date Duration Calculator
Exact days, weeks, months between two dates
Hours Calculator
Work hours, overtime, and weekly paycheck calculator
What makes our time & date calculators different
Calendar-Aware Date Math
Leap years, varying month lengths, and DST transitions are all handled correctly.
Live Countdowns
Countdowns keep ticking in the background - switch tabs and come back, no drift.
Student-Friendly GPA
Weighted and unweighted scales, custom 4.0/4.3/5.0/10.0 systems, semester and cumulative.
Time Zone Aware
Built on IANA time zones for accurate cross-city meeting and travel planning.
Frequently asked questions about our time and date calculators
Are the date calculations accurate for leap years?
Yes. We use proper date math that accounts for leap years, varying month lengths, and DST where relevant. Birthdays on Feb 29 are celebrated on Mar 1 in non-leap years.
Can the GPA calculator handle weighted courses?
Yes, it supports honors and AP weighting for high school, plus custom scales for college (4.0, 4.3, 5.0, 10.0).
Do countdown timers keep running in the background?
Yes. Once started, the countdown tracks real time and stays accurate when you switch tabs or come back later.
How does the time zone converter work?
Enter any two cities or IANA time zones (e.g. America/New_York, Asia/Shanghai) and we will show the current time difference plus recommended meeting times across the day.
Can I use the age calculator for someone born on a leap day?
Yes. The age calculator returns the correct years/months/days and treats Feb 29 birthdays correctly across leap and non-leap years.