CalDiff
Visa & Immigration Date Calculator
Calculate date differences with precision. Understand inclusive vs exclusive counting, and never make an off-by-one error on your visa again.
Date Calculator
Calculate Date Difference
Calendar Days (Inclusive)
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Feb 2 to Feb 4 = 3 days (Feb 2, Feb 3, Feb 4)
Calendar Days (Exclusive)
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Feb 2 to Feb 4 = 2 days (the gap)
Business Days
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Useful for work permits or business visa calculations
Weekend Days
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Helps understand how many rest days fall within your stay
Reverse Calculator: Find Your Last Allowed Day
Enter your arrival date and the number of days your visa allows. We'll calculate your last legal day.
Off-by-One Explanation
The Off-by-One Question
If I arrive February 2nd with a 10-day visa, when must I leave?
February
Answer: You must DEPART by February 11th. Staying until February 12th would be an overstay.
Last Legal Day = Arrival Date + (Allowed Days - 1)
Counting Methods and Tips
Understanding the Counting Methods
Calendar Days (Inclusive)
Both the start and end dates count as full days. This is the standard for most visa and immigration calculations.
Feb 2 to Feb 4 = 3 days (Feb 2, Feb 3, Feb 4)
Calendar Days (Exclusive)
The gap between dates, not counting both endpoints. Useful for calculating nights stayed or time elapsed.
Feb 2 to Feb 4 = 2 days (the gap)
Business Days
Only weekdays (Monday-Friday) are counted. Weekends are excluded.
Useful for work permits or business visa calculations
Weekend Days
Only Saturdays and Sundays within the range.
Helps understand how many rest days fall within your stay
Visa Tips
Visa Duration Counting
Most countries count your arrival and departure days as full days. A "10-day visa" means 10 calendar days including both arrival and departure.
Schengen Area
The Schengen 90/180 rule counts days inclusively. Both entry and exit days count toward your 90 days.
US B1/B2 Visa
Your I-94 shows the "admit until" date. You must leave ON or BEFORE this date, not the day after.
Grace Periods
Some countries have grace periods for overstay, but penalties can include fines, bans, or deportation. Always leave before your authorized stay expires.