Date Add Subtract Calculator

Add or subtract days, weeks, months, or years from any date. Perfect for planning future dates, calculating deadlines, and complex date math operations.

Date Math Calculator

Perform date arithmetic with multiple operations

Base Date

Date Operations

Quick Presets

Key Features

Add or subtract days, weeks, months, years

Multiple operations in sequence

Handles leap years and month-end dates

Batch processing for multiple dates

Quick preset calculations

CSV export and clipboard copy

Understanding Date Math

Days: Simple addition/subtraction, accounts for leap years

Months: Handles varying month lengths (28-31 days)

Years: Considers leap years and calendar adjustments

Edge Cases: Jan 31 + 1 month = Feb 28/29 (last day)

Sequences: Operations applied in order for complex calculations

Tips & Strategies

90-Day Notice: Use +90 days for advance notifications

Legal Deadlines: Calculate filing dates with -1 day safety buffer

Quarterly Planning: Use +3 months -1 day for exact quarters

Batch Processing: Process multiple dates with same operations

Retroactive Dates: Use -6 months for historical analysis

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Frequently Asked Questions

Can I perform multiple operations on the same date?

Yes! You can add multiple operations like "+3 months -5 days" to perform complex date calculations in sequence.

How accurate are month and year calculations?

Our calculator handles varying month lengths and leap years accurately using the date-fns library, ensuring precise calculations even for edge cases.

What is batch mode used for?

Batch mode allows you to perform the same operation on multiple dates and export the results as a CSV file, perfect for project planning and bulk calculations.

Can I calculate dates in the past?

Absolutely! Use the subtract operation to calculate dates in the past from any given base date.

How do I use quick presets?

Click any preset button (+1 Week, +1 Month, etc.) to automatically configure common date calculations. You can then modify or add more operations.

What formats does the calculator support?

Input dates use the standard YYYY-MM-DD format. Results are displayed in human-readable format and can be copied in ISO format.

How does the calculator handle edge cases?

The calculator properly handles leap years, month-end dates (like Jan 31 + 1 month), and automatically adjusts for varying month lengths using date-fns library.