Help Center
How to use our calculators, common questions, and every tool in one place.
How to Use the Tools
- Pick a tool from the menu above or the index below.
- Enter your values — dates, times, or numbers, depending on the calculator.
- Click Calculate (most tools also compute live as you type).
- Read and copy your result — every result shows clear formats and a copy button.
All calculations happen instantly in your browser. Nothing is uploaded, stored, or shared — your data never leaves your device.
Common Questions
Are the calculators accurate?
Yes. Calculations use well-tested algorithms (based on the standard Gregorian calendar and IANA timezone rules) and are verified against authoritative sources, including leap-year and DST edge cases.
Do you handle time zones and daylight saving time?
The Time Duration, Time Zone, and Time Addition tools handle timezones and DST automatically. The Date Calculator works on calendar days and does not shift for DST — day-level math is unaffected by clock changes.
How do you count days between dates?
By default the Date Calculator excludes the start day and includes the end day (Day 1 is the day after the start) — the standard convention for legal and contract deadlines. You can switch to counting both days when needed.
Is there a 12-hour / 24-hour toggle?
Yes — most time-based tools let you switch between 12-hour (AM/PM) and 24-hour display.
Do you store my inputs?
No. Every calculation runs locally in your browser with JavaScript. We have no server-side calculation endpoints and store nothing you enter.
Can I use the tools on my phone?
Yes — the entire site is responsive and works on mobile, tablet, and desktop browsers.
All Tools
- Age CalculatorCalculate your exact age from your date of birth.
- Average Time CalculatorAverage multiple times (HH:MM:SS) into a single mean time.
- Chronological Age CalculatorExact age in years, months and days for assessments.
- Date CalculatorDays between dates, or add/subtract days, weeks, months and years.
- Daylight Savings Time Clock ChangeWhen clocks change — spring forward and fall back dates and times.
- Elapsed Time CalculatorTime elapsed between a start and end time.
- Hours CalculatorHours between two times, plus minutes and seconds.
- Hourly to Salary CalculatorConvert hourly wage to annual salary and back.
- Speaking Time CalculatorWords to speech time based on words per minute.
- Speed Distance Time CalculatorCalculate speed, distance or time from any two values.
- Time Addition & Subtraction CalculatorAdd or subtract hours, minutes and seconds from a time.
- Time and a Half CalculatorOvertime pay at 1.5x, 2x and 3x rates.
- Time Card CalculatorCalculate clock-in/out times and work hours.
- Time Duration CalculatorDuration between two times or dates, with timezone support.
- Time From Now CalculatorWhat time will it be hours, minutes or seconds from now.
- Time to Decimal CalculatorConvert hours and minutes to decimal hours.
- Time Unit ConverterMinutes to hours, seconds to minutes and more.
- Time Zone ConverterConvert times between any two time zones, DST handled.
- Work Hours CalculatorTotal work hours from clock-in/out times with breaks.
Still Need Help?
Email us at contact@timecalculator.day and we'll get back to you. For legal matters, see our Privacy Policy, Terms of Service, and Cookie Policy.