Free Online Tools & Calculators

JSON Formatter & Validator Format, validate and minify JSON with clear error messages.

GPA Calculator Convert the credits you earn at each grade into a 4.0-scale GPA.

Age Calculator Find your exact age in years, months and days, plus total days lived and your next birthday.

Break-Even Calculator Find how many units you must sell to cover fixed and variable costs. Credit Card Payoff Calculator See how long a credit card balance takes to clear and what the interest really costs. Debt-to-Income Calculator Calculate your debt-to-income ratio the way mortgage lenders do. Income Tax Calculator (US Federal, 2026) Estimate 2026 US federal income tax for a single filer with the standard deduction. Inflation Calculator See what inflation does to prices and to the purchasing power of your money. Loan Amortization Calculator Get your monthly loan payment and a year-by-year amortization breakdown. Mortgage Calculator Estimate your monthly mortgage payment with principal, interest, taxes and insurance. Profit Margin Calculator Find profit, margin and markup from cost and selling price. ROI Calculator Work out your return on investment and annualized return (CAGR). Retirement Calculator Project your retirement savings at retirement age from savings and monthly contributions. Salary Calculator Convert pay between hourly, weekly, biweekly, monthly and annual salary. Savings Goal Calculator Find out how long it will take to reach a savings goal with monthly contributions. Simple Interest Calculator Calculate simple interest on a loan or deposit in seconds: I = P x r x t.

BMR Calculator Calculate your basal metabolic rate with the Mifflin-St Jeor equation. Calorie Calculator Turn your BMR into daily calorie targets for maintaining, losing or gaining weight.

Average Calculator Mean, median, mode, sum, range and more from any list of numbers. Percentage Change Calculator Calculate the percentage increase or decrease between two values.

Bulk DA Checker Check the Domain Authority (DA) of up to 20 websites at once, free — with Page Authority, Spam Score, domain age and registrar for each site. Bulk DR Checker Check the Domain Rating (DR) of up to 20 websites at once, free — Domain Rating by Ahrefs for every site on your list. Domain Age Checker Check the age of up to 20 domains at once, free — registration date, exact age, expiry date and registrar for each one. Website Traffic Checker See a website's monthly traffic, global rank and domain age, free — live data from Similarweb where available.

Case Converter Convert text between UPPER, lower, Title, Sentence, camelCase, snake_case and more. Word Counter Count words, characters, sentences and paragraphs, with reading and speaking time.

Bulk Email Finder Find the public contact emails of up to 10 websites at once — scans up to 10 pages per site, decodes protected addresses, picks out each site’s best contact email, and checks the business’s public social profiles and web listings when a site publishes none, free. Password Generator Generate strong random passwords with a length slider and character options. QR Code Generator Turn any link or text into a scannable QR code and download it as a PNG. Unit Converter Convert length, weight, temperature, volume and speed between US and metric units.