UTILITIES · FREE TOOL
Date calculator
Count days between dates or add calendar months and days.
Your inputs
Enter your values, then calculate.
Decimal-point numbers; displayed rounding does not change internal values. Calculations stay on this device.
YOUR RESULT
Make the numbers clear.
Save calculation JSON ↓Calculation breakdown
Scroll sideways to see every column. You can also focus the table and use the arrow keys.
How this calculation works
Date difference is end−start, excluding inclusive-day counting. Add mode first moves by calendar months and clamps to that month’s last day, then adds signed calendar days. Dates1900–2199; no time zones, business calendars or holiday lookup.
Check the assumptions
Use the stated units and conventions. This tool supports the workflow described here; it does not infer missing information or outside rules.