Guides

How to Calculate Your GPA (Step by Step) Learn how to calculate your GPA on the 4.0 scale, including weighted GPA by credit hours, with a clear worked example. What Grade Do I Need on My Final Exam? Use a simple formula to find the exact score you need on your final exam to reach your target grade in the class. How to Count Words in an Essay (and Hit Your Word Count) Quick ways to count words and characters in an essay, plus tips for hitting a word count without padding. APA vs. MLA: How to Cite Sources Correctly The difference between APA and MLA citation styles, when to use each, and how to format citations correctly. How to Download a YouTube Thumbnail in HD Download any YouTube video thumbnail in full resolution for free — no software needed. Step-by-step guide. How to Calculate Percentages (Quick Guide) Calculate a percentage of a number, percentage change, and "X is what percent of Y" with simple formulas and examples. How to Convert an Image to PDF (Free, In Your Browser) Turn JPG or PNG images into a PDF for free without uploading your files. Combine multiple images into one PDF. How Long Will My Speech or Video Take? (Words to Time) Estimate how many minutes a speech, script, or video will take based on word count and speaking pace. How to Merge PDF Files for Free (Without Uploading Them) Combine multiple PDFs into one file for free, right in your browser — no software, no uploads, no watermark. How to Calculate BMI (Formula + What It Means) The BMI formula in metric and imperial units, the weight categories, and what BMI does and doesn't tell you. How to Calculate a Tip (15%, 18%, 20%) Calculate a tip and split the bill fast, with the simple percentage trick and a quick reference table. How to Calculate a Discount and Sale Price Work out how much you save and the final price after a percentage discount — plus how to find the original price. How to Create a Strong Password (That You Can Actually Use) What makes a password strong, why length beats complexity, and how to generate and manage passwords safely. How to Calculate Compound Interest (With Examples) The compound interest formula explained simply, with a worked example and why compounding frequency matters. How to Calculate Hours Worked (and Pay) Add up hours from clock-in and clock-out times, subtract breaks, convert to decimal hours, and figure your pay. How to Convert Celsius to Fahrenheit (and Back) The Celsius-to-Fahrenheit formula, the reverse formula, a quick mental shortcut, and a handy reference table. How to Calculate Your Exact Age Work out your age in years, months, and days from your date of birth — and avoid the common off-by-one mistake. How to Calculate Running Pace Calculate your running pace per mile or kilometer, convert pace to speed, and use pace to predict race times. How to Calculate a Monthly Loan Payment The monthly loan payment formula explained, with a worked example for a car or personal loan. How to Calculate Your Grade in a Class Calculate your overall course grade from weighted categories like homework, tests, and the final. How to Read and Write Roman Numerals Learn the Roman numeral symbols, the subtraction rule, and how to convert numbers to Roman numerals and back.