Time Converter — Free Online Tool

What Is Time Converter?

A free online time converter. Convert between milliseconds, seconds, minutes, hours, days, weeks, months, and years. Real-time conversion with a full reference table.

Time conversion between different units — seconds, minutes, hours, days, weeks, months, and years — is a surprisingly frequent need in project planning, cooking, exercise tracking, and scheduling. Time Converter handles eight time units with real-time bidirectional conversion and a full reference table.

Enter a value in any unit field and all others update instantly. For example, enter 1 in the day field and see 24 hours, 1,440 minutes, 86,400 seconds, and 0.003 years. This makes it easy to understand the relationships between different time units at a glance — useful for project scheduling, exercise duration tracking, or converting between academic and calendar time.

The month and year conversions are based on the average lengths. One month is defined as 30.4375 days (365.25 / 12), and one year as 365.25 days (accounting for leap years). This means that converting from months or years to days gives an accurate average, but individual calendar months and years can vary. For precise date-to-date duration calculations, a dedicated date difference calculator is more appropriate.

The converter handles very small and very large values. Milliseconds capture sub-second precision for computing and scientific contexts. The full range from milliseconds to years covers everything from processor timing to project planning horizons. The swap button lets you quickly reverse any conversion for cross-checking — enter a result in the target unit and verify the source value.

Real-World Use Cases for Time Converter

Converting a Project Timeline from Days to Hours

A project plan estimates 45 business days for completion. Enter 45 in the day field to get 1,080 hours (assuming 24-hour days) or 360 working hours (if using 8-hour work days, divide 1,080 by 24 and multiply by 8). The tool gives you the raw 24-hour conversion as a starting point.

Calculating Exercise Duration in Different Units

A fitness plan recommends 150 minutes of moderate exercise per week. Enter 150 in the minutes field to see 2.5 hours, 0.104 days, and 0.015 weeks. The per-week view helps you plan how to distribute exercise across your weekly schedule.

Converting Milliseconds to Readable Time for Performance Metrics

A web page load time is measured at 3,500 milliseconds. Enter 3,500 in the ms field to get 3.5 seconds. For API response times in microseconds, convert to milliseconds first, then to seconds. This helps developers communicate performance metrics in the most readable unit.

Why Use Time Converter?

8 units: ms, s, min, h, day, week, month, year
Real-time conversion as you type
Full reference table for all units
Swap direction with one click

How to Use Time Converter — Step by Step

Enter a time value.

Select from and to units.

View the result instantly.

Copy any value from the reference table.

Who Is Time Converter Best For?

project planning
cooking
exercise
scheduling

Pro Tips for Time Converter

1For precise duration calculations between specific dates (e.g., "how many days between Jan 1 and Mar 15"), use a dedicated date difference calculator instead of average conversions.
2The month conversion (30.44 days) is an average. If you need to know "3 months from today", count months on the calendar rather than multiplying 30.44 by 3.
3When converting cooking times (e.g., a recipe that says "bake for 40 minutes"), the minutes-to-hours conversion helps you plan multiple dishes: 40 min = 0.67 hours.
4For payroll and billing, hours-to-days conversion depends on the definition of a work day (typically 8 hours). Apply your business standard after using the tool for the raw 24-hour conversion.

Time Converter — Frequently Asked Questions

How many seconds are in a day?

1 day = 86,400 seconds (24 hours x 60 minutes x 60 seconds).

How many hours are in a year?

1 year = 8,766 hours (365.25 days x 24 hours). The .25 accounts for leap years.

How accurate are the unit conversions?

Conversions use NIST-standard conversion factors with precision up to 15 significant digits. Currency exchange rates update every 10 minutes from a free data source.

Can I convert between any two units?

Yes. Each converter supports all standard units within its category. For example, the length converter handles metric, imperial, and nautical units.

Is Time Converter really free to use?

Yes, Time Converter is completely free with no hidden charges, no usage limits, and no premium tiers. You can use it as often as you need without signing up or providing any personal information.

Ready to Use Time Converter?

Free online tool — works in your browser, no sign-up required. Start using it right now.

Try It Now