Free online tools.
One stack.
Resize exam photos, edit and compress PDFs, and work out income tax or salary — 168 free tools that run in your browser, with no signup.
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NewJust added to Cubestack
See all 168 tools- Tic Tac ToeVs computer or a friend.
- SudokuFree puzzles in four levels.
- YouTube Thumbnail DownloaderSave thumbnails in HD and more.
- Stair CalculatorSteps, risers, run and stringer.
- Paint CalculatorLitres of paint for any room.
- Concrete CalculatorVolume, cement bags, sand, aggregate.
- Resistor Color CodeDecode 4, 5 and 6-band resistors.
- Ohm's Law CalculatorVoltage, current, resistance, power.
- Punnett Square CalculatorGenetic crosses and ratios.
- Chemical Equation BalancerBalance equations with an atom check.
- Molar Mass Calculatorg/mol and mass % from a formula.
- PIN GeneratorRandom PINs that avoid common ones.
All 168 tools,sorted by job.
Search the toolsText & Writing
Resume, typing, Hindi & Tamil, word count.
- Auto-saveNotepad & Live CounterWrite, count words live, export to PDF.Open
- InstantWord CounterCount words, chars, lines & reading time.Open
- InstantCase ConverterUPPER, lower, Title & snake_case instantly.Open
- InstantLorem GeneratorGenerate placeholder paragraphs & sentences.Open
- InstantRemove Duplicate LinesDeduplicate lines, keep order or sort.Open
- InstantSort LinesAlphabetical, numeric, reverse & shuffle.Open
- Client-sideText to SpeechSpeak any text with browser voices.Open
- Dev toolDiff CheckerCompare two texts line by line.Open
- Dev toolRegex TesterTest RegExp with live highlight & groups.Open
- FreeResume BuilderMake an ATS-friendly CV and download a PDF.Open
- InstantTyping Speed TestWPM in English, Hindi, Tamil, Kannada.Open
- InstantHindi TypingType in English, get Hindi (Devanagari).Open
- NudiKannada TypingNudi keyboard or English letters, any font.Open
- KannadaNudi to Unicode ConverterNudi ↔ Unicode Kannada, Word files too.Open
- InstantTamil TypingType in English, get Tamil script.Open
- VoiceSpeech to TextDictate in English, Hindi, Kannada & more.Open
- CopyFancy Text GeneratorBold, italic, script & bubble text to copy.Open
- AudioMorse Code TranslatorText to Morse and back, with sound.Open
- InstantBinary TranslatorText to binary, hex, decimal and back.Open
- InstantNumber to WordsSpell numbers in words, ordinals, cheques.Open
- WritingCitation GeneratorAPA, MLA, Harvard & Chicago citations.Open
- WritingReading Level CheckerFlesch, grade level & Fog scores.Open
- WritingSyllable CounterCount syllables, with a haiku check.Open
- InstantText RepeaterRepeat text or emoji up to 10,000×.Open
- InstantEmail Signature GeneratorHTML signatures for Gmail & Outlook.Open
Image & Media
Exam photo, passport photo, compress, QR.
- Client-sideImage ConverterPNG → JPG / WebP, client-side via Canvas.Open
- Client-sideImage CompressorShrink JPG/WebP with quality slider.Open
- Client-sideImage ResizerResize by pixels or percent, keep aspect.Open
- Client-sideImage CropperCrop with preset ratios, preview & download.Open
- InstantQR Code GeneratorCreate QR for URL, text, Wi-Fi & more.Open
- FreevCard QR Code GeneratorBusiness card QR: scan to save your contact.Open
- InstantQR Code ReaderScan QR from image in your browser.Open
- IndiaExam Photo & Signature ResizerResize to 20 KB, 50 KB for SSC, UPSC, IBPS forms.Open
- Client-sidePassport Photo MakerPassport & visa size photos with a print sheet.Open
- OCRImage to Text (OCR)Extract text from photos and scans.Open
- PrintBarcode GeneratorCode 128, EAN-13, UPC barcodes as PNG/SVG.Open
- Client-sideCollage MakerCombine 2–9 photos into one collage.Open
- Client-sideVideo to GIFTurn a video clip into an animated GIF.Open
- DesignColor Palette GeneratorHarmonious palettes from one colour.Open
- DesignColor Contrast CheckerWCAG AA and AAA contrast ratio.Open
- DesignImage Color PickerPick HEX and RGB colours from images.Open
- DesignSVG OptimizerShrink SVG files with SVGO.Open
- InstantYouTube Thumbnail DownloaderNewSave thumbnails in HD and more.Open
PDF Tools
Edit, compress, merge, split, protect.
- Client-sidePDF EditorEdit text, sign, highlight, fill forms, reorder pages — in your browser.Open
- Client-sidePDF MergerMerge multiple PDFs into one — local.Open
- Client-sidePDF SplitterSplit PDF by page ranges.Open
- Client-sideImage to PDFTurn JPG/PNG/WebP into a PDF.Open
- Client-sideCompress PDFReduce PDF file size in your browser.Open
- Client-sidePDF to WordConvert PDF to editable Word (.docx).Open
- Client-sidePDF to JPGTurn PDF pages into JPG or PNG images.Open
- Client-sideAdd Page NumbersNumber PDF pages, any position & style.Open
- Client-sideWatermark PDFStamp CONFIDENTIAL, DRAFT or your name.Open
- Client-sideProtect PDFAdd a password with AES-256.Open
- Client-sideUnlock PDFRemove the password from your PDF.Open
- Client-sideSign PDFDraw or type a signature and sign a PDF.Open
- Client-sideRotate PDFRotate all or some PDF pages.Open
- Client-sidePDF to TextExtract all text from a PDF.Open
Developer
JSON, Base64, hash, JWT & more.
- Dev toolJSON FormatterFormat, validate & beautify JSON instantly.Open
- Dev toolBase64 Encode / DecodeEncode & decode Base64 with UTF-8.Open
- Dev toolURL Encoder / DecoderEncode & decode URLs & query strings.Open
- Dev toolHash GeneratorSHA-1/256/384/512 via Web Crypto.Open
- Dev toolJWT DecoderDecode header & payload, no verify.Open
- Dev toolUUID GeneratorGenerate v4 UUIDs, bulk copy.Open
- Dev toolColor ConverterHEX ↔ RGB ↔ HSL with picker.Open
- Dev toolCode MinifierMinify & beautify JS/CSS/JSON.Open
- Dev toolMarkdown PreviewLive Markdown → HTML preview.Open
- Dev toolJSON to CSV ConverterJSON to CSV and CSV to JSON.Open
- Dev toolXML FormatterBeautify, minify and validate XML.Open
- Dev toolSQL FormatterFormat SQL for MySQL, Postgres & more.Open
- Dev toolHTML to MarkdownConvert HTML into clean Markdown.Open
- Dev toolUnix Timestamp ConverterEpoch time to date and back.Open
- Dev toolCron Expression GeneratorExplain cron and see next runs.Open
- Dev toolImage to Base64Images to data URIs and back.Open
- Dev toolString Escape / UnescapeJSON, HTML, URL, SQL, regex escaping.Open
- CSSCSS Unit Converterpx to rem, em, pt, vw and more.Open
- CSSCSS Gradient GeneratorLinear, radial and conic gradients.Open
- CSSBox Shadow GeneratorLayered CSS box-shadows with preview.Open
- CSSCSS Grid GeneratorGrid layouts with CSS and Tailwind.Open
Calculators
Scientific, fractions, age, GST, units & science.
Everyday maths and loans · 7
- InstantPercentage CalculatorPercent of, increase & decrease.Open
- InstantEMI CalculatorLoan EMI, interest & schedule.Open
- InstantLoan CalculatorAmortization & total cost.Open
- InstantGST CalculatorAdd or remove GST, split CGST/SGST.Open
- InstantAge CalculatorExact age with milestone progress.Open
- InstantPercentage Change CalculatorPercentage increase or decrease.Open
- MathsRatio CalculatorSimplify, solve and split ratios.Open
Dates and time · 4
School and exams · 14
- InstantScientific CalculatorTrig, logs, powers, roots, factorials.Open
- InstantCGPA to PercentageCBSE, AICTE, VTU, Anna Univ & more.Open
- ExamsNegative Marking CalculatorExam score after negative marks, and when to guess.Open
- StudentsGPA CalculatorSemester & cumulative GPA, 4.0 or 10-point.Open
- StepsFraction CalculatorAdd, subtract, multiply, divide fractions.Open
- MathsStatistics CalculatorMean, median, mode, standard deviation.Open
- MathsProbability CalculatorEvents, binomial, nPr and nCr.Open
- StepsQuadratic Equation SolverSolve ax² + bx + c = 0 with steps.Open
- StepsPythagorean Theorem CalculatorHypotenuse or missing side, with angles.Open
- MathsLogarithm CalculatorLog, ln, log₂, antilog, any base.Open
- MathsMatrix CalculatorAdd, multiply, determinant, inverse.Open
- MathsFactorial CalculatorExact n! up to 5000.Open
- MathsPrime Number CheckerIs it prime? Factors and nearest primes.Open
- InstantRoman Numeral ConverterNumbers to Roman numerals and back.Open
Science · 5
- ScienceMolar Mass CalculatorNewg/mol and mass % from a formula.Open
- ScienceChemical Equation BalancerNewBalance equations with an atom check.Open
- SciencePunnett Square CalculatorNewGenetic crosses and ratios.Open
- ScienceOhm's Law CalculatorNewVoltage, current, resistance, power.Open
- ScienceResistor Color CodeNewDecode 4, 5 and 6-band resistors.Open
Measuring and building · 7
- InstantUnit ConverterLength, weight, temp & more.Open
- MathsArea CalculatorArea and perimeter of 10 shapes.Open
- MathsVolume CalculatorVolume of cylinders, spheres, boxes & more.Open
- IndiaLand Area ConverterAcre, guntha, cent, bigha, kanal & more.Open
- BuildConcrete CalculatorNewVolume, cement bags, sand, aggregate.Open
- BuildPaint CalculatorNewLitres of paint for any room.Open
- BuildStair CalculatorNewSteps, risers, run and stringer.Open
Health & Fitness
Calories, BMI, pregnancy, sleep, water.
- InstantBMI CalculatorBody mass index with category.Open
- HealthCalorie CalculatorDaily calories, BMR, TDEE and macros.Open
- HealthPregnancy Due Date CalculatorDue date and weeks pregnant.Open
- HealthOvulation CalculatorFertile window and ovulation dates.Open
- HealthSleep CalculatorBest bedtime or wake-up time by sleep cycles.Open
- HealthWater Intake CalculatorHow much water to drink a day.Open
- HealthCalories Burned CalculatorCalories burned by 21 activities.Open
- FitnessOne Rep Max CalculatorEstimate your 1RM and training loads.Open
Everyday & Devices
Timers, random numbers, mic, webcam & keyboard tests.
- InstantStopwatch & TimerOnline stopwatch with laps, and a countdown timer.Open
- ShareCountdown TimerDays, hours and minutes to any date.Open
- FocusPomodoro Timer25-minute focus sessions with breaks.Open
- FairRandom Number GeneratorRandom numbers, dice, coin flip, name picker.Open
- DeviceKeyboard TestCheck every key on your keyboard works.Open
- DeviceTouchpad & Mouse TestClicks, scrolling, pinch and touch.Open
- DeviceMic TestCheck your microphone with a live level.Open
- DeviceWebcam TestCheck your camera, resolution and fps.Open
- VideoScreen RecorderRecord your screen with sound, no install.Open
- MusicGuitar TunerTune guitar, bass, ukulele with your mic.Open
- MusicMetronomeSteady beats 30–250 BPM, tap tempo.Open
- GameSudokuNewFree puzzles in four levels.Open
- GameTic Tac ToeNewVs computer or a friend.Open
Security
Passwords, hashing, UUID.
- InstantPassword GeneratorStrong passwords with custom rules.Open
- InstantPassword StrengthScore & crack-time estimate locally.Open
- Private2FA Code GeneratorTOTP codes from a 2FA secret key.Open
- PrivateText Encryption (AES)Lock a message with a password.Open
- InstantPIN GeneratorNewRandom PINs that avoid common ones.Open
SEO & Web
Meta, OG, robots, sitemap, DNS.
- SEOMeta Tag GeneratorTitle, description & OG tags.Open
- SEOOpen Graph PreviewPreview OG/Twitter cards.Open
- SEORobots.txt GeneratorBuild robots.txt with sitemap.Open
- SEOSitemap GeneratorGenerate XML sitemap URLs.Open
- SEODNS LookupA, MX, TXT via dns.google.Open
- SEODNS Propagation CheckerSee if DNS changes reached servers worldwide.Open
- SEOWebsite Down CheckerIs it down or just me? Test from 40 places.Open
- SEOSchema Markup GeneratorJSON-LD for FAQ, Product, Local Business.Open
- SEOSERP PreviewSee your page in Google results.Open
- SEOKeyword Density CheckerTop words and phrases in your text.Open
- SEOUTM BuilderCampaign tracking links for Analytics.Open
Money & Tax
Income tax, salary, SIP, FD, GST invoice.
- InstantCurrency ConverterLive rates, offline fallback.Open
- InstantDiscount CalculatorSale price & savings.Open
- InstantTip CalculatorTip, split & per-person total.Open
- InstantTimezone ConverterConvert time across zones.Open
- IndiaIncome Tax CalculatorFY 2026-27, new vs old regime.Open
- IndiaSalary CalculatorCTC to monthly in-hand salary.Open
- InstantSIP CalculatorMutual fund SIP & lump-sum returns.Open
- InstantFD CalculatorFixed deposit maturity & interest.Open
- InstantRD CalculatorRecurring deposit maturity amount.Open
- InstantPPF CalculatorPPF maturity, tax-free.Open
- InstantEPF CalculatorProvident fund at retirement.Open
- InstantAmount in WordsRupees in words for cheques & invoices.Open
- IndiaGST Invoice GeneratorTax invoice with CGST/SGST/IGST as PDF.Open
- Any currencyMortgage CalculatorHome loan payment and amortization.Open
- Any currencyCompound Interest CalculatorSavings growth with monthly deposits.Open
- BusinessProfit Margin CalculatorMargin, markup and selling price.Open
The tools people open most
Image Compressor
Original · IMG_2041.jpg
4.2 MB
Compressed · WebP
0.9 MB
Quality75%
79% smaller · processed in your browser, 0 bytes uploaded
Compress Download
Image Compressor
Shrink photos for forms, portals and email by moving one slider. You see the new size before you download, and the photo never leaves your phone or laptop.
Your files stay with you
Image, PDF, text, code and calculator tools are built on what your browser already has: Canvas, Web Crypto, pdf-lib and jsPDF. The work happens on your device, so there is no upload to wait for and nothing stored on a server.
Instant
First, open a tool. No signup, nothing to install.
One second
Then drop in your file, link or text.
A few seconds
Your browser does the work. The file never leaves your device.
Instant
Finally, save the result to your Downloads.
Questions, answered
Price
Yes. All 168 tools are free to use, with no trial and no paywall. The site is supported by ads shown around the tools, never inside your files.
Privacy
Almost never. Image, PDF, text, code, security and calculator tools run inside your browser, so files stay on your device. Only DNS lookup, link previews and currency rates need our server or a public API.
Signup
No. Open any tool and use it straight away. There is nothing to install. A free account is optional — it lets you save your favourite tools.
Phones
Yes. Every tool works in a modern mobile browser on Android or iPhone, as well as on laptops and desktops.
Limits
No. Use the tools as often as you like. Very large files are limited only by your device's memory.
Every tool page also answers questions about that tool. Pick a tool