Help - How to Use Date Time Calculator

I will guide you with the things that you need to know in order to use the calculators on this site. There are a lot of helpful date and time calculator tools you can use even if you are figuring out "What year was 52 years ago?" or "What time will it be 3 hours and 45 minutes from now?", we'll give a quick guide for you.

🚀 What this site does?

Dealing with time and date computations sometimes is truly confusing. Doing math on time units, working with leap years, counting months, these things gets complicated most of the time. That's the very reason why I built this tool.

  • Instantly calculate days ago or days from now.
  • Add or subtract days, weeks, months, years even quarters.
  • Doing math with hours, minutes, seconds and milliseconds.
  • Show results with very accurate dates even addition meaningful and significant tidbits of details.

Example: 👉 If today is August 16, 2025 and you type in 85 years ago, the calculator tells you it was August 16, 1940 (Friday)

📚 How to Use the Calculators?

The time and date calculators on this website is built so that it is so easy to use and understand. Even in a quick glace you'll easily know where to place your inputs and what inputs you need to enter.

Even with this clarity of inputs, there's a step by step guide you can find on each calculator. Let's walk though a popular calculators and quickly make a guide:

Years Ago Calculator

  1. Go to the Years Ago Calculator page.
  2. Type in a number (e.g., “52”).
  3. Hit enter (or the page auto-calculates).
  4. You'll see these results:
    • The exact date (month, day, year).
    • The day of the week.
    • Extra details (how many months, weeks, or days ago that was).

Add Time Calculator

Exactly compute what's the total time if you add two time units.

  1. Go to the Add Time Calculator page.
  2. Enter the hours, minutes, seconds, milliseconds of the time entries you want to add.
  3. Click on +Add Row button if you want to insert more time entries.
  4. Press the Calculate button to generate your result.

💭 Common Questions

Here are answers to the most common things people ask:

Do I need JavaScript enabled?

Yes. The date and time calculators run in your browser, so make sure JavaScript is turned on. Without it, the page loads but results won’t appear.

Do you save what I type?

No. Everything runs on your device. Nothing is stored. Refreshing clears your inputs.

Is it free?

Yes, 100% free.

How accurate is it?

Very accurate. The math is handled using reliable date/time libraries.

Can I use this on mobile?

Yes. The calculators are designed to work on desktop, tablet, and phone screens.