Time Calculator

Add or subtract time values, calculate time from a date, and solve time expressions in one clean tool.

⏱️ Fill any blank field as 0, choose your operation, and click  Calculate.

Time Calculator in Expression

Use expressions like 1d 2h 3m 4s + 4h 5s - 2030s.

Allowed units: d (days), h (hours), m (minutes), s (seconds). Operators: + and −.
Clear Expression Mode

About This Time Calculator

This Time Calculator helps you perform three common time operations: time ± time, date ± time, and time expression calculation. It is useful for scheduling, shift planning, turnaround estimates, travel durations, production workflows, and daily planning.

Blank fields are treated as 0, so you can quickly calculate only the units you need (for example, just minutes and seconds).

What You Can Do

  • Time ± Time: Add or subtract two durations (days, hours, minutes, seconds)
  • Date ± Time: Find a new date/time after adding or subtracting a duration
  • Expression Mode: Calculate compact expressions like 2h 30m - 45s + 1d

How to Use

Tab 1: Enter two time values and choose Add or Subtract. The result is normalized automatically (for example, 90 seconds becomes 1 minute 30 seconds).

Tab 2: Select a start date/time, choose + or −, and enter the duration. The calculator returns the exact resulting date and clock time.

Tab 3: Type an expression using d h m s units. Spaces are optional between values and units (for example 30m or 30 m).

Common Time Units

UnitDefinition
day24 hours = 1,440 minutes = 86,400 seconds
hour60 minutes = 3,600 seconds
minute60 seconds
secondBase SI unit of time
week7 days
common year365 days
leap year366 days
millisecond1/1000 second
microsecond1/1,000,000 second
nanosecond1/1,000,000,000 second

Practical Use Cases

Work shifts: Add break durations or calculate total duty time.

Deadlines: Add hours/minutes to a starting timestamp for delivery or reporting cutoffs.

Content production: Sum clip lengths or subtract intro/outro durations from total runtime.

Travel and logistics: Add transit time to a departure date/time to estimate arrival.

FAQ

Can I subtract a larger time from a smaller one?
Yes. The result can be negative, and the calculator shows the normalized duration with a minus sign.
Does the calculator support 24-hour time?
Yes. In the Date ± Time tab, choose 24-hour in the time mode dropdown.
What units are allowed in expression mode?
Only d, h, m, and s. Example: 1d 4h - 30m + 15s.

Related: Date Calculator · Age Calculator · Hours Calculator