CalcNow

Free Online Calculators

Fast, free, and private. All calculations happen in your browser — no data is ever sent to a server.

100% Browser-Based — No Sign-Up Required

Finance

View Finance hub →

Compound Interest Calculator

Calculate future value with compound interest

Loan Calculator

Monthly payments, total interest for any loan

Mortgage Calculator

Home loan payments with down payment

Rent vs Buy

Compare total cost of renting vs buying

Salary Calculator

Convert between hourly, monthly, annual salary

Tip Calculator

Split bills and calculate tips easily

Discount Calculator

Find final price after discounts

Auto Loan Calculator

Car loan payments with trade-in value

ROI Calculator

Return on investment and annualized ROI

Margin & Markup

Profit margin, markup, and selling price

Health & Life

View Health & Life hub →

BMI Calculator

Body Mass Index with health categories

BMR Calculator

Basal Metabolic Rate (Mifflin-St Jeor equation)

TDEE Calculator

Daily calorie needs based on activity level

Body Fat Calculator

Body fat % using US Navy method

Age Calculator

Exact age in years, months, and days

Unit Conversion

View Unit Conversion hub →

Fahrenheit ↔ Celsius

Temperature: °F, °C, and Kelvin

Inch ↔ CM

Length: inches, cm, meters, feet

Pound ↔ KG

Weight: pounds, kg, stones, ounces

MPG (Gas Mileage)

Fuel economy: MPG US/UK, L/100km

Cooking Converter

Cups, tbsp, tsp, fl oz, ml, L

Shoe Size Converter

US, UK, EU, JP, CM — men & women

Unit Converter

Length, weight, and temperature

Percentage Calculator

3-in-1 percentage calculations

Everyday Tools

View Everyday Tools hub →

Date Calculator

Date difference and add/subtract days

Time Between Dates

Days, weeks, months, business days

Age Difference

Between two people's birthdays

GPA Calculator

Calculate your college GPA

Password Generator

Generate secure random passwords

Why Use CalcNow?

CalcNow is a collection of 28 free online calculators designed to make everyday math simple and accessible. Whether you need to figure out monthly loan payments, check your BMI, convert units, or calculate a tip, CalcNow has you covered. Every calculation runs 100% in your browser using JavaScript — no data is ever uploaded to a server, and no account or sign-up is needed.

Unlike many online calculator sites that require server-side processing or limit free usage, CalcNow is completely free with no restrictions. Use any calculator as many times as you want, on any device. The site loads instantly and works offline once loaded, making it a reliable tool you can bookmark and return to anytime.

Most Popular Calculators

  • Loan Calculator — Enter any loan amount, interest rate, and term to instantly see your monthly payment and total interest cost. Works for personal loans, auto loans, and student loans.
  • BMI Calculator — Calculate your Body Mass Index using your height and weight. See which WHO health category you fall into and understand what the numbers mean.
  • Percentage Calculator — Three calculation modes in one: find a percentage of a number, figure out what percent one number is of another, or calculate percentage change.
  • Salary Calculator — Convert between hourly, weekly, bi-weekly, monthly, and annual salary. See how changes in your hourly rate affect your yearly income.

How It Works

Simply choose a calculator from the categories above, enter your numbers, and see results update instantly as you type. There are no "Calculate" buttons to press — every calculator provides real-time results. Each calculator page also includes a detailed explanation of how the calculation works, step-by-step usage instructions, and answers to frequently asked questions.

CalcNow covers four main categories: Finance (loans, interest, salary, ROI), Health & Life (BMI, body fat, calorie needs), Math & Conversion (percentages, unit conversion), and Everyday Tools (dates, GPA, passwords). All calculators use industry-standard formulas and are regularly verified for accuracy.