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Percentage calculatorFour percentage calculations in one: X% of Y, what percent X is of Y, and increasing or decreasing a value by a percentage.Average (mean) calculatorCompute the mean, sum and count of a list of numbers.Derivative CalculatorCompute single, partial, implicit and directional derivatives symbolically.Percentile calculatorFind the value at a given percentile in a list of numbers.CalculatorEvaluate math expressions with parentheses, powers and modulo, live.3D Distance CalculatorCompute the distance between two points in space, with an isometric view, the Δx / Δy / Δz components and the midpoint.Absolute Value Equation SolverSolve absolute-value equations like |x+3| = 5, 3|x+2| = 12 or |x+1| = |x−3| with step-by-step case analysis and exact solutions.Absolute Value Inequality SolverSolve absolute-value inequalities such as |x+3| < 5 or |x−2| > 3 and get the solution as an interval, with AND/OR reasoning explained step by step.
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BMI calculatorCompute your Body Mass Index and weight category.VAT calculatorAdd or remove VAT from a price at any rate.Temperature converterConvert between °C, °F, K and more. Free temperature converter, instant and accurate.QR Code GeneratorCreate a QR code from any text or URL — free.Password generatorGenerate a strong, random password — free and secure.Word counterCount words, characters, sentences and reading time instantly.Hash generatorCompute 15 hashes (MD5, SHA-256, SHA-3, CRC-32…) of a text or a file.UUID generatorGenerate UUID v7, v4, v5, v3, v1 or v6 in bulk, in several output formats.Base64 Encoder / DecoderEncode and decode Base64 online — free.JSON formatterFormat, beautify or minify JSON — with instant validation.Color converterConvert a colour to HEX, RGB, HSL, HSV, CMYK, LAB and OKLCH, with contrast.Regex testerTest a regular expression and see what it does: matches highlighted in the text, every capture group listed, a replace panel, and the pattern read back to you piece by piece. Flags are toggles that say what they change, and a pattern that could freeze the page is flagged before you run it.
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ExplainerThe Same .ics File Can Mean Five Different TimesiCalendar writes a start time in one of three ways, and only one of them is unambiguous. A meeting written with a named zone, converted on machines in Paris, New York and Honolulu, spanned nineteen hours and changed day.ExplainerA Recurring Event Is One Line in the CSV, Not TwelveAn .ics file stores a weekly meeting once, with a rule attached. Export it to CSV and you get a single row for the whole series — which is the file being honest, not the converter losing rows.ExplainerAn .mbox Is Messages Glued End to End, and the Glue Is a LineOne file, thousands of messages, separated by a line beginning From. The format has one famous weakness, and it is the reason a message can lose its ending without anything reporting an error.ExplainerAn Attachment Grows by a Third Inside the EmailMail carries files as text, three bytes written as four characters. A 10 MiB attachment occupies 13.68 MiB of the message, which is why a 25 MB limit really means about 18 MiB of files.How-toOpening an .eml File Without Telling the SenderA saved message is a text file you can read anywhere. The catch is that opening it in something that loads remote images announces the moment you did — which is what a tracking pixel is for.GuideNappy Sizes Overlap, and the Smaller One Usually WinsAt 7.5 kg a baby is inside both the size 2 and the size 3 band. Take the 2: a snugger fit leaks less. The step to watch for is the weight at which the smaller band ends, and at 7.5 kg that is eight and a half months away.