Time & Date
Processed locallyTime Duration Calculator
Add signed durations accurately including milliseconds and long hours.
Tool options · presets, sharing & more
Presets & sharing: options only, never files, text or passwords. Undo/redo: editable form values, not file selection or generated results.
How to Use Time Duration Calculator
Enter values using the date, time, currency or CSV format shown beside each field.
Choose weekend rules, shift handling or calculation direction where available.
Calculate and review the result and rounding notes.
Copy or download the report. Undefined ratios are reported as null rather than fabricated values.
What This Tool Does
Add signed durations accurately including milliseconds and long hours. Read the format requirements and practical limits in the interface before processing.
Common Use Cases
This tool processes files and input in this browser tab. Its processing code does not upload them to a server. Loading this page and fetching uncached app files uses an internet connection. Optional usage analytics requires your consent and excludes input, filenames, passwords and generated content. Form undo history and result transfers stay in session memory. Explicitly saved presets contain approved settings only.
Offline use is not verified for this tool. Keep an internet connection available to load its page, code and any additional dependencies.
Frequently Asked Questions
What should I check before using Time Duration Calculator?
Add signed durations accurately including milliseconds and long hours. Read the format requirements and practical limits in the interface before processing.
Does this tool work offline?
Offline use is not verified for this tool. Keep an internet connection available to load its page, code and any additional dependencies.
Can I keep my original file?
Yes. Processing creates a separate result and does not overwrite your source file. Keep the original until you have reviewed the output.