Date & Time

Time Span Calculator

Convert durations, compare date ranges, or add spans with a seconds baseline.

Translate hours into days, compare two timestamps, or project an end date from a duration with compact business-time settings for workdays, workweeks, and standard hours per day.

Your Input and Get Results

Calculation type

Duration

Duration unit

Start date

Start time

End date

End time

Start date

Start time

Duration to add

Duration unit

Output unit

Months use 30 days and years use 365 days for consistent conversion.

Business settings

Workdays per week

Hours per workday

Results

Converted output -

Enter values and calculate to see the output.

Output value

Chosen unit

Seconds baseline

Total seconds

Business days

Using settings

Business weeks

Workweek estimate

Time span chart

Converted share Seconds share

Results table

Metric	Value
Enter values and calculate to see the output.

Precautionary guidance

Confirm start and end timestamps before sharing.
Document business-hour assumptions for stakeholders.
Use consistent time zones across reports.
Double-check month and year assumptions.
Recalculate after schedule changes.
Keep baseline seconds in exports.

Use the export tools to share results with teams.

How to use this calculator

Choose A Mode

Select whether you are converting a duration, comparing two timestamps, or adding time to a start date.

Enter Time Inputs

Provide the relevant duration or dates. For business reporting, open the business settings to set workdays.

Export The Summary

Download CSV, Excel, or PDF outputs to share scheduling assumptions and your baseline seconds.