Date & Time Calculator

Try Android app: https://play.google.com/store/apps/details?id=com.tiptinker.datecalculator&hl=en

A dual-mode date calculator that answers two common questions: “How many days between two dates?” and “What date is X days/weeks/months from today?” Useful for project planning, contract deadlines, pregnancy trackers, travel countdown, and any scenario where you need precise date math.

Why Use This Date Calculator?

• Two modes — date difference and date add/subtract in one tool.
• Multi-unit output — results shown in days, weeks, months, years, and hours simultaneously.
• Locale-aware — resulting dates are displayed in a full human-readable format.
• No dependencies — uses native JavaScript Date API, works offline.

Key Features

• Date Difference: Pick two dates and instantly see the gap in days, weeks, months, and hours.
• Add / Subtract: Start from any date, add or subtract days, weeks, months, or years.
• Negative Values: Enter negative numbers to subtract time (e.g., -30 days = 30 days ago).
• Today Default: Both modes default to today’s date for convenience.

How it Works

Date difference is calculated as the absolute millisecond delta between two JavaScript Date objects, then converted to days (÷86400000), weeks, months (÷30.4375), and years (÷365.25). Date addition uses the native setDate, setMonth, and setFullYear methods, which automatically handle month-end overflow.

Try the Date Calculator

Switch between “Date Difference” and “Add / Subtract” tabs, enter your dates, and click Calculate.