Free Online Calculators

Instant calculators for age, date & time, and more. No signup, no tracking — all calculations run privately in your browser.

Calculator Categories

Age Calculators

Exact age, dog age, cat age, Korean age, biological age, retirement, pregnancy, and more.

24 Tools Browse Age Tools

Date & Time Calculators

Time calculator, hour calculator, deadline tracker, expiry date, time converter, and more.

14 Tools Browse Date & Time Tools

Popular Calculators

Age Calculator

Calculate your exact age in years, months, days, hours, and seconds from your birthdate.

Dog Age Calculator

Convert your dog's age to human years using the latest veterinary research.

Time Calculator

Add or subtract time durations, or find the time between two clock times.

Deadline Calculator

Calculate a deadline date by adding days, weeks, or months to a start date.

Korean Age Calculator

Calculate your age using the traditional Korean age counting system.

Hour Calculator

Calculate hours between two times or add up a weekly timesheet.

Biological Age Calculator

Estimate your biological age based on health factors and lifestyle.

Time Converter

Convert between seconds, minutes, hours, days, weeks, and months instantly.

Expiry Date Calculator

Calculate when a product expires from its manufacture date and shelf life.

Retirement Age Calculator

Calculate when you can retire based on your birth year and country.

Week Calculator

Calculate the number of weeks between two dates or from today.

Gestational Age Calculator

Calculate pregnancy gestational age in weeks and days, plus estimated due date.

About Random Tools

Random Tools offers free calculators across multiple categories — from age and date calculators to time converters and deadline trackers. All results are instant and every calculation runs entirely in your browser. No data is sent to any server, no account needed.

Why Use Random Tools?

Every calculator is completely free with no signup, no downloads, and no ads. Your information stays private — we process everything client-side. Our tools work on any device: desktop, tablet, or phone. We're continuously adding new categories and calculators.