Kastavo
Free online tools to get things done in seconds
Convert files, calculate values, generate codes, transform text, and more. Right in your browser.
85 free tools, in 3 languages
Categories
ConvertersConvert units and currencies.CalculatorsCalculators for everyday use.FinancialFinancial calculators.GeneratorsGenerate UUIDs, passwords, codes.ValidatorsValidate tax IDs and emails.DevelopmentHandy tools for developers.TextFormat and transform text.ImageEdit and convert images.PDFMerge, split, convert PDFs.ColorsPick and convert colors.
Popular tools
CalculatorsAge CalculatorCalculate exact age in years, months, and days from a birth date.CalculatorsBMI CalculatorCalculate your BMI and see the WHO classification.CalculatorsPercentage CalculatorCalculate percentages: what X% of Y is, increases, discounts, and more.ColorsColor PickerPick a color and see HEX, RGB and HSL instantly.ColorsHEX ↔ RGB ConverterConvert colors from HEX to RGB and RGB to HEX.ColorsContrast Checker (WCAG)Check the contrast between two colors and WCAG compliance.PDFMerge PDFMerge several PDFs into one document, in any order.ImageCompress ImageReduce an image's file size with quality control.GeneratorsQR Code GeneratorGenerate QR Codes for text, links, Wi-Fi, Pix, and more, free.
New tools
DevelopmentBase64 ConverterConvert text to Base64 and Base64 back to text, with full Unicode support.DevelopmentHTML, CSS & JavaScript MinifierShrink HTML, CSS, and JavaScript by removing whitespace, comments, and unnecessary code.DevelopmentHash GeneratorGenerate SHA-256, SHA-384, and SHA-512 hashes of any text, using the native Web Crypto API.DevelopmentJWT DecoderDecode a JWT and see its header, payload, and expiration — without verifying the signature.DevelopmentRegex TesterTest regular expressions against a text and see matches, groups, and positions in real time.DevelopmentUnix Timestamp ConverterConvert a Unix timestamp to date and time, and a date back to a timestamp — in seconds or milliseconds.
Why use Kastavo?
100% free
Every tool is free, with no hidden limits or required sign-up.
Fast and straightforward
Instant results, right in your browser, nothing to install.
Privacy
Whenever possible, processing happens locally in your browser — your files aren't sent to any server.
Multiple languages
Content in Portuguese, English and Spanish, with units and formats for your language.
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