Date Calculator

Add or subtract days, weeks, months, and years from any date — or count the span between two dates. Every result shows the day of the week and a plain-English summary.

Add / Subtract from a Date
Local

What the Date Calculator does

The Date Calculator answers two of the most common calendar questions: “What date is X days from now?” and “How many days are between two dates?” It handles months and leap years correctly, so adding one month to January 31 lands on the last valid day of February rather than overflowing into March.

Add days to a date

Pick a start date, keep Add selected, and enter the number of days, weeks, months, or years. For example, 90 days after June 23, 2026 is Monday, September 21, 2026. The result includes the day of the week and the total number of days changed.

Subtract days from a date

Switch to Subtract to move backward through the calendar — useful for finding start dates, look-back windows, and historical deadlines. One year and seven days before June 23, 2026 is June 16, 2025.

Count days between dates

Use the Days Between tab to measure the span between two dates. You’ll get the total number of days, a weeks-and-days view, and a calendar breakdown in years, months, and days.

  • Deadlines and project milestones
  • Due dates, renewals, and notice periods
  • Anniversaries, countdowns, and planning
  • Look-back and look-forward windows

Date Calculator vs Time Calculator

The Time Calculator works within the clock — hours, minutes, and seconds. The Date Calculator works across the calendar — days, weeks, months, and years. Both run on the same precise engine and live under one roof at TimeCalculator.ai.