Time Duration Calculator

Calculate the exact hours and minutes between two times, with overnight support.

Start Time

End Time

About Time Duration Calculator

This time duration calculator computes the exact hours and minutes between any two times of day. It automatically handles overnight periods — if your end time falls after midnight or you're calculating a shift that spans two days, simply toggle the overnight option. Results are displayed in hours:minutes format as well as total minutes and decimal hours. Perfect for tracking work shifts, study sessions, travel time, or any elapsed time calculation.

Overnight Handling

Toggle overnight mode for time spans that cross midnight — perfect for night shifts and late-night events.

Hours & Minutes

Results shown in standard HH:MM format so you can read the duration at a glance.

Decimal Conversion

See the duration as decimal hours too — useful for payroll, billing, and time tracking purposes.

Time Tracking

Ideal for tracking work hours, study sessions, cooking times, travel duration, and project time estimates.

📋 Common Use Cases

Personal Record Keeping

Calculate your exact age for official forms, track days until important events, or determine what day of the week a past date fell on.

Academic Planning

Calculate your GPA, determine what grade you need on a final exam, or track cumulative academic performance across semesters.

Travel Planning

Estimate trip fuel costs, compare driving vs flying expenses, or calculate time zone differences for international travel planning.

Everyday Convenience

Quick date math for scheduling, countdowns to special occasions, or figuring out how many days between two dates for billing or contracts.

🪜 How to Use This Tool

  1. Enter your starting values
    Input dates, grades, distances, or fuel economy numbers depending on the specific calculator. Clear labels guide you through each field.
  2. Adjust any optional settings
    Set unit preferences, grading scales, or vehicle details to match your specific scenario.
  3. Review calculated results
    Results appear instantly with clear formatting. Date calculators show breakdowns in years/months/days; grade calculators show required scores.
  4. Use results for planning
    Apply the calculations to your scheduling, study planning, or travel budgeting. Recalculate anytime as your inputs change.

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Frequently Asked Questions

Are these calculators really free?▼
Yes. All calculators on iluv.tools are completely free. No signup, no account, no credit card required. Every calculation runs instantly in your browser.
Is my data sent anywhere?▼
Absolutely not. All calculators are pure client-side JavaScript. Your numbers, dates, and inputs never leave your browser. No server processing, no tracking.
How accurate are these calculators?▼
Calculators use standard mathematical formulas with double-precision floating point. Results match industry-standard financial and scientific calculations.
Can I use calculators on mobile?▼
Yes. All calculators work on mobile browsers (iOS Safari, Android Chrome) with responsive layouts.