📅 Date Calculator 2026 — Your Time-Bending Bestie
Calculate days between dates, add/subtract days, find business days, due dates & more — all in seconds!
📊 Understanding Date Calculations
The Date Calculator is the ultimate 2026 tool for anyone who needs to work with dates without the headache of manual counting. Whether you're a project manager calculating deadlines, an expectant parent tracking your due date, or simply curious about how many days until your vacation, this calculator handles all the complexity for you.
Our calculator automatically accounts for leap years, varying month lengths, and even excludes weekends for business day calculations. From counting days between two dates to calculating your exact age in years, months, and days — save time and eliminate errors with instant, accurate results!
🛠️ Pick Your Calculator
📝 How to Use the Date Calculator
- Select Calculator Type: Choose from 6 options — Days Between, Add Days, Subtract Days, Business Days, Due Date, or Age Calculator.
- Enter Your Dates: Click on the date fields to select dates from the calendar picker. Ensure start date comes before end date for accurate results.
- Add Numbers (if needed): For Add/Subtract calculators, enter the number of days you want to add or subtract.
- Click Calculate: Press the calculate button to get instant, detailed results including breakdowns in weeks, months, and years.
- Review Results: Check the comprehensive breakdown showing multiple time units and additional insights.
💡 Tips for Accurate Results
- Leap Years: Our calculator automatically handles February 29 in leap years — no manual adjustment needed.
- Business Days: Weekends (Saturday & Sunday) are automatically excluded. Holidays are not excluded by default.
- Due Date: Pregnancy calculations are estimates only — always consult your healthcare provider.
📐 Date Calculation Formulas & Methods
📅 Days Between Two Dates
The simplest calculation converts both dates to milliseconds since epoch, subtracts them, then converts the difference back to days. This automatically handles varying month lengths and leap years.
💼 Business Days Calculation
Weekend Days ≈ (Total Days ÷ 7) × 2
Business days exclude Saturdays and Sundays. For precise calculation, we iterate through each day and count only weekdays (Monday-Friday).
🤰 Pregnancy Due Date (Naegele's Rule)
Or: Due Date = Conception Date + 266 days (38 weeks)
Naegele's Rule, established in the 1800s, assumes a 28-day menstrual cycle. The actual due date may vary based on individual cycle length and other factors.
📊 Date Calculator Examples
Example 1: Project Deadline — Days Between Dates
Scenario: Maya is a project manager who needs to know how many days her team has to complete a project starting February 1, 2026 and ending May 15, 2026.
End Date: May 15, 2026
Calculation: May 15 - Feb 1 = 103 days
Example 2: Contract Terms — Add Days to Date
Scenario: Alex signed a 90-day contract on January 15, 2026 and needs to know when it expires.
Days to Add: 90
Calculation: Jan 15 + 90 days = April 15, 2026
Example 3: Business Days — Delivery Estimate
Scenario: An online order promises delivery in 10 business days. If ordered on Monday, March 2, 2026, when will it arrive?
Business Days: 10
Excluding: 2 weekends (4 days)
Calendar Days Needed: 14
📊 Date Calculation Reference Table 2026
| Time Period | Days | Weeks | Business Days (approx.) |
|---|---|---|---|
| 1 Week | 7 | 1 | 5 |
| 2 Weeks | 14 | 2 | 10 |
| 1 Month (avg) | 30.44 | 4.35 | ~22 |
| 1 Quarter | 91 | 13 | ~65 |
| 6 Months | 182 | 26 | ~130 |
| 1 Year | 365 | 52 | ~260 |
| 1 Leap Year | 366 | 52+2 | ~261 |
| Pregnancy (LMP) | 280 | 40 | ~200 |
Note: Business days vary based on holidays. Standard calculation assumes Mon-Fri work week.
💡 Important Tips for Date Calculations
- Leap Year Check: 2024, 2028, and 2032 are leap years. February has 29 days in these years, affecting date calculations.
- Month Lengths: Remember "30 days hath September, April, June, and November" — all others have 31 except February!
- Business vs Calendar Days: Always clarify which is meant in contracts. 30 business days ≈ 42 calendar days (6 weeks).
- Time Zones: Date calculators work with calendar dates, not times. For international deadlines, specify the time zone.
- Legal Deadlines: For legal or contract purposes, consult a professional to verify critical deadline calculations.
❓ Frequently Asked Questions
Enter your start date and end date in the "Days Between" calculator tab, then click calculate. The result shows the total days, plus breakdowns in weeks, months, and years. The calculation automatically accounts for varying month lengths and leap years.
Yes! Our calculator automatically handles leap years. A leap year occurs every 4 years (except centuries not divisible by 400). So 2024 and 2028 are leap years, adding February 29. All calculations incorporate this automatically.
Calendar days include every day (weekends and holidays). Business days count only weekdays (Monday-Friday), excluding weekends. For example, 10 business days equals approximately 14 calendar days. This distinction is crucial for contracts, deliveries, and legal deadlines.
The calculator uses Naegele's Rule (LMP + 280 days), which is the standard medical estimation method. However, only about 5% of babies arrive on the exact due date. Most babies are born within 2 weeks before or after. Always consult your healthcare provider for personalized guidance.
Absolutely! The calculator works both forward and backward in time. Use "Subtract Days" to find past dates, or use "Days Between" with any historical dates. This is useful for calculating how long ago events occurred or backdating documents.
Use the "Age Calculator" tab. Enter your birth date and the date you want to calculate age on (usually today). You'll get your exact age in years, months, and days, plus total days alive, hours, and days until your next birthday!
Use the "Add Days" calculator. Enter today's date as the start date and enter 90 in the days field. Click calculate to see the exact future date, accounting for varying month lengths and leap years.
The standard calculator excludes weekends (Saturday and Sunday) but does not automatically exclude public holidays, as these vary by country and region. For critical calculations, manually subtract the number of holidays in your date range.
🔗 Related Calculators
⚠️ Important Disclaimer
This date calculator is provided for informational and planning purposes only. While we strive for accuracy, results should not be the sole basis for critical decisions in legal, financial, or medical contexts. Pregnancy due dates are estimates — always consult healthcare professionals. For legal deadlines, verify with appropriate professionals. Different jurisdictions may use different day-counting conventions. Last updated: February 2026