Free online tools
Calculators, converters, text and developer tools. Open one and use it right away: no sign-up, nothing to install, your data stays on your device.
Math
- Scientific calculatorTrigonometry, logarithms, powers, roots and factorials, with a touch keypad and keyboard input.
- Fraction calculatorAdd, subtract, multiply and divide fractions and mixed numbers, with every step shown.
- Decimal to fraction calculatorTurn a decimal, even a repeating one like 0.(3), into the simplest fraction and mixed number.
- Fraction simplifierReduces a fraction to lowest terms and shows the Euclidean algorithm steps behind the GCD.
- Proportion calculatorSolve a/b = c/x for x, in direct or inverse proportion.
- Aspect ratio calculatorSimplify a width and height to a ratio, or find the missing side for 16:9, 4:3, 21:9 and more.
Finance
- Loan calculatorMonthly payment, total interest and a month-by-month amortization schedule.
- Mortgage calculatorMonthly payment, total interest, extra payments and a schedule by year.
- Down payment calculatorDown payment, loan amount, LTV and how long it takes to save the money.
- Loan comparisonTwo loans side by side: monthly payment, interest and total cost, fees included.
- Refinance calculatorNew payment, monthly savings, break-even month and lifetime interest difference.
- Student loanMonthly payment and total interest, with a grace period and interest capitalization.
Date & time
- Days between datesDays between two dates, as weeks, months or years, with business days.
- Age differenceThe exact age gap between two people from their birth dates.
- Half birthdayThe date six months after a birthday, with days left and the next five.
- PTO accrualProject paid time off hours from the accrual rate per pay period.
- Pay periodsEvery pay date in a year for weekly, biweekly, semi-monthly or monthly pay.
- Working days calculatorBusiness days between two dates, without weekends and the days off you list.
Health
- Pregnancy weight gainTotal gain and weekly rate from your pre-pregnancy BMI (IOM 2009), for one baby or twins, plus the range by week.
- Bra size converterBand and cup from your underbust and bust measurements, and the same size in US, UK, EU, FR and AU systems.
- Bicycle gear calculatorGear ratio, gear inches, development and speed at a cadence from chainring, sprocket and tyre.
- BMI calculatorBody mass index in kg/cm or lb/ft, WHO category and healthy weight range.
- Bowling score calculatorTen-pin bowling scorer with strike and spare bonuses, the 10th frame and a running total per frame.
- Climbing grade converterCompare French sport, YDS, UIAA and British technical climbing grades with a common chart.
Education
- GPA calculatorSemester and cumulative GPA on the 4.0 scale from credits and letter grades, with optional weighting.
- Grade calculatorWeighted course grade from categories, or the final exam score you need for a target grade.
- Study plannerA day-by-day study schedule from the exam date, topics and daily hours, with review days.
- Curve grade calculatorCurve a score by adding points, lifting the top score to the maximum, the square root method or a bell curve to a target mean and standard deviation.
- CGPA to percentageCGPA × 9.5 for CBSE, an editable multiplier for other boards, percentage back to CGPA and a rough 4.0 GPA estimate.
- Test score calculatorTest points to percent and letter grade, with an editable scale and a full grading table.
Home
- AC BTU calculatorRoom air conditioner size in BTU/h from area, sun, people and kitchen.
- Appliance energy calculatorYearly and monthly energy cost of one appliance, with its standby power counted separately.
- BBQ meatRaw meat and side dishes to buy for a barbecue by guests, appetite and bone-in or boneless cuts.
- Bucket list makerA bucket list with categories and done ticks, a progress count and plain-text export, saved in your browser.
- 50/30/20 budget calculatorSplit monthly income into needs, wants and savings using the 50/30/20 rule of thumb.
- Cleaning schedule generatorSpreads chores by room and frequency over the days you choose, as a printable 4-week plan.
Cars
- Fuel trip cost calculatorFuel needed and cost of a drive from distance, consumption and fuel price, split between the people in the car.
- Oil change interval calculatorNext oil change by odometer or by months, whichever comes first, with an estimated date.
- Tire size calculatorSidewall, overall diameter, circumference and revs per km or mile of a tyre size, plus the speedometer effect of a new size.
- Carpool cost splitterFuel, tolls and parking for a shared trip, split per person, with an optional free ride for the driver.
- Speedometer error calculatorThe error of a speedometer in percent, from a change of tyre size or from a GPS speed, with the true speed it implies.
- Fuel tank range calculatorDistance you can drive on the fuel in the tank, to empty and down to a reserve you choose.
Hobbies
- Chess clockTwo-player game clock with presets, custom time, Fischer increment or delay, pause and low-time warning.
- ScoreboardBig plus and minus buttons for two to six teams, with a choice of step, saved in your browser.
- Card game score keeperA players-by-rounds score table with totals and a leader, for any card game, saved in your browser.
- Fretboard note finderHighlights a note or scale on a guitar, bass or ukulele neck for common tunings or your own.
- 3D print costFilament and electricity cost of a print, with an allowance for failed prints.
- Aquarium volume calculatorWater volume and weight of a rectangular, cylindrical or bow-front aquarium from its dimensions.
Unit converters
- ABV calculatorAlcohol by volume from original gravity and final gravity, with the standard formula and a higher-gravity alternative.
- Acceleration converterm/s², g-force, ft/s², Gal, km/h per second and mph per second.
- Angle converterDegrees, radians, gradians, arcminutes, arcseconds, turns and NATO mils.
- Angular velocity converterrad/s, rpm, rev/s, degrees per second and per minute.
- Area converterSquare meters and feet, acres, hectares, square kilometers and miles.
- Astronomical distance converterkm, au, light-seconds, light-minutes, light-years, parsecs, kpc and Mpc.
Text
- Acronym generatorBuilds an acronym from the first letters of each word in a phrase, with an option to skip small words and a letter-by-word breakdown.
- Add line numbersNumbers each line of a text with the start number, separator and alignment you choose; blank lines can be skipped.
- Add prefix and suffix to linesPut text before and after every line, with an option to skip empty lines.
- Adverb counterHighlights and counts likely English adverbs (-ly words and a list of common ones) and shows their share of the text.
- Anagram solverWords from a set of letters: anagrams or shorter words, with blanks.
- ASCII art generatorBig letters from your text in three built-in character styles, ready to copy.
Developer
- .gitignore generatorCombine ready-made ignore lists for common stacks into one .gitignore, without duplicates.
- Ascii85 encoderAscii85 (Adobe or plain) and Z85 conversion for text or hex bytes.
- Base32 encoderConvert text or bytes to Base32 and back with the standard, base32hex or Crockford alphabet.
- Base58 encoderBase58 and Base58Check conversion with the Bitcoin alphabet, for text or hex bytes.
- Base64 encoderConvert text to Base64 and back, with UTF-8 support and a URL-safe option.
- BCD converterConvert decimal to packed and unpacked BCD (8421) and decode BCD back to decimal.
Generators
- Baby name generatorName ideas for a girl or a boy, filtered by origin and first letter.
- Band name generatorRandom band names for rock, indie, metal and pop, up to 30 at a time.
- Barcode generatorCreate Code 128 and EAN-13 barcodes and download them as PNG or SVG.
- Bingo card generatorPrintable 75-ball and 90-ball bingo cards, plus a number caller for game night.
- Book title generatorBook title ideas for fantasy, thriller, romance and non-fiction, built from templates and word lists.
- Business name generatorName ideas from your keyword in modern, classic, playful or tech styles.
Color
- Accessible color finderAdjust a text color just enough to meet WCAG AA or AAA contrast on a background.
- Border radius generatorSet each corner radius, in px or percent, see the shape and copy border-radius.
- Box shadow generatorBuild a layered box-shadow with a live preview and copy the CSS.
- Color averageAverage a list of colors three ways: sRGB, linear light and perceptual OKLab.
- Color blindness simulatorSee an image the way people with common types of color vision deficiency do.
- Contrast matrixCheck WCAG contrast between every pair of colors in a palette at once.
Images
- Add text to imageWrite on your picture with draggable text boxes, your choice of font, colour and outline, and save as PNG or JPG.
- Blur and pixelate imageDraw boxes on a picture to blur or pixelate faces, number plates, addresses or any private detail.
- Booklet page calculatorPage order for a folded saddle-stitch booklet on double-sided sheets, with blank pages added to reach a multiple of 4.
- Circle crop toolCrop a picture into a circle with zoom and position, and save a PNG with transparent corners.
- Crop factor calculatorFull-frame equivalent focal length and aperture for APS-C, Micro Four Thirds, 1-inch and custom sensors.
- Depth of field calculatorNear and far limits of acceptable sharpness plus the hyperfocal distance for your lens settings.
- Add Page Numbers to PDFPut page numbers on every page of a PDF, with your position, format, start number and size.
- Add Text to PDFStamp text onto PDF pages with a chosen font, size, colour and position.
- Certificate makerMake a printable certificate with a title, name, reason, date and signature lines in three templates.
- Chore chart generatorPrintable weekly chore chart: one page per person with your chores down the side and the days across.
- Delete PDF PagesRemove pages from a PDF by range or by clicking thumbnails, then download the shorter file.
- Dot grid paper generatorPrintable dot grid paper for notebooks and sketching, with your spacing, dot size and margins.
Device tests
- Typing speed testType common English words for 30, 60 or 120 seconds and get your WPM and accuracy.
- What is my browserShow your browser and version, operating system, engine, language, cookie and touch support, and copy it all as text.
- Microphone testCheck that your microphone picks up sound with a live level meter and a peak mark.
- Speaker testCheck stereo speakers and headphones with left, right and both channel tones and a frequency sweep from 20 Hz to 20 kHz.
- Webcam testPreview your camera live, see its resolution and frame rate, switch cameras and save a snapshot.
- Keyboard testerPress keys and see them light up on a QWERTY layout with key, code and location shown.