FreeTools Blog
Guides & How-Tos
Clear, practical explainers on the calculators and tools you use every day — the formulas, the examples, and how to get the right answer.
HealthBMR vs TDEE: What's the Difference?BMR and TDEE are two critical metrics for weight loss and fitness. Discover what each means, how they differ, and why both matter for your goals.Read →GuideCelsius to Fahrenheit: Formula, Chart & ExamplesMaster temperature conversion with our complete guide: formula, practical examples, easy-to-use chart, and common mistakes. Convert any temperature instantly.Read →GuideCM to Inches: How to Convert (With Chart)Quick guide to converting centimeters to inches with the formula, worked examples, and a printable conversion chart. No downloads required—convert instantly online.Read →HealthHow Much Water Should You Drink a Day?Stop guessing. Learn the real science behind daily water intake, personalized formulas based on your weight and activity level, and how to use the Water Intake Calculator to find your optimal hydration.Read →FinanceHow to Calculate ROI (Formula & Examples)Discover the ROI formula, step-by-step calculations, and real-world examples to measure investment performance and compare opportunities effectively.Read →GuideHow to Count Words and Characters OnlineMaster word and character counting with our free online tools. Learn why these metrics matter for SEO, social media, and academic writing.Read →DeveloperHTTP Status Codes Explained (200, 404, 500)Learn what HTTP status codes mean: 200 (success), 404 (not found), 500 (server error), and dozens more. Essential for developers debugging APIs and web requests.Read →GuideKG to Lbs: Simple Weight Conversion GuideMaster KG to pounds conversion with our simple formula and real-world examples. Convert any weight instantly with our free online tool.Read →DeveloperRegex Basics: A Beginner's GuideMaster regular expressions with clear explanations of metacharacters, quantifiers, and real-world examples. A practical guide for developers new to regex.Read →FinanceSimple vs Compound Interest: The DifferenceSimple interest calculates returns on principal only, while compound interest grows on both principal and accumulated earnings. Discover how this difference transforms your money over time.Read →DeveloperWhat Is a MIME Type? Content-Type ExplainedMIME types tell browsers and servers what kind of data they're receiving. Master Content-Type headers, common file types, and fix media delivery issues.Read →DeveloperWhat Is Base64 Encoding? How It WorksBase64 encoding converts binary data into ASCII text for safe transmission. Discover how it works, practical applications, and common pitfalls in web development.Read →GuideCompound Interest Explained (Formula, Examples, Power of Compounding)Compound interest is the mechanism behind wealth accumulation. Understand the formula, how frequency matters, and why starting early compounds your advantage.Read →GuideGST Calculator Guide: How to Add and Remove GST (India)Master GST calculation with step-by-step formulas, real examples, and insights into tax slabs. Calculate inclusive and exclusive prices instantly.Read →GuideHow EMI Is Calculated (Formula + Examples)EMI (Equated Monthly Instalment) is calculated using the reducing-balance formula. This guide explains the maths, shows real examples, and explores how tenure and interest rate affect your payments.Read →GuideHow to Calculate BMI (Formula, Chart & Examples)BMI (Body Mass Index) is a simple tool to assess weight relative to height. Learn the formula, interpretation, and why BMI has limitations.Read →GuideHow to Calculate Percentages (With Examples)Percentages are everywhere—from discounts to test scores to salary increases. Learn the core formulas and how to calculate them accurately with real-world examples.Read →GuideJPEG vs WebP: A Practical Guide to Faster ImagesWebP offers smaller file sizes and advanced features like transparency and animation, but JPEG remains widely supported. Here's how to choose and when to convert.Read →GuidePNG vs JPG: Which Image Format Should You Use?Choosing between PNG and JPG affects file size, quality, and compatibility. Understand the differences and when to use each format.Read →GuideSIP vs Lumpsum: Which Is Better for You?SIP spreads your investment over time to reduce risk, while lumpsum offers timing advantages if you have capital ready. Discover which strategy works best for your financial goals.Read →GuideThe 100 Best Free Online Tools (2026)A hand-picked guide to the internet's most useful free online tools across finance, health, conversion, text, image, PDF, and developer utilities—all browser-based, no signup.Read →GuideThe Best Free Online PDF Tools (Merge, Split, Convert)A roundup of the most useful free PDF tools that work right in your browser—merge, split, rotate, convert, add watermarks, and more without uploading your files.Read →