1. What is the 90 Days Back Calculator?

The 90 Days Back Calculator helps you determine the date exactly 90 days prior to a given date. This is particularly useful for monthly financial, legal, or medical contexts where a 3-month lookback period is required.

2. How Does the Calculator Work?

The calculator uses simple date arithmetic:

Where:

• Today — The reference date (defaults to current date)
• 90 days — Fixed 3-month period (approximately)

Note: The calculation accounts for varying month lengths and leap years.

3. Importance of Date Calculation

Details: Accurate date calculations are crucial for financial reporting, legal deadlines, medical follow-ups, and any situation requiring a precise 90-day lookback period.

4. Using the Calculator

Tips: Enter any date in YYYY-MM-DD format or use today's default date. The calculator will compute the date exactly 90 days prior.

5. Frequently Asked Questions (FAQ)

Q1: Does this account for leap years?
A: Yes, the PHP date functions automatically account for leap years in the calculation.

Q2: Is this exactly 3 months or exactly 90 days?
A: This calculates exactly 90 days, which may differ slightly from calendar months due to varying month lengths.

Q3: Can I use this for business days only?
A: No, this calculates calendar days. For business days, you would need a different calculation.

Q4: What's the maximum/minimum date range?
A: The calculator works with any valid date from 1970 through 2037 on most systems.

Q5: Can I calculate forward dates too?
A: This specific calculator only calculates backward, but the same principle could be used for forward dates.