Our complete toolbox
Explore 78 free online tools — calculators, converters and utilities grouped by what you need. No sign-up, no install: every tool runs right in your browser.
You can also address a tool directly as https://useful-utilities.com/<tool>/ or as <tool>.useful-utilities.com — both reach the same page.
78 free tools in 8 topics — every card opens in a new window, so this page stays your launcher.
Finance & Personal
Loans, taxes, budgets, savings and everyday money maths.
Budget PlannerTotal, share of income per item, and surplus or deficit from income plus expense lines written as label: amount, up to 20 lines.Compound Interest CalculatorFinal amount, growth and a year-by-year interest walk for an investment compounded at any frequency from yearly to daily.Credit Score EstimatorEstimate a credit score from how much of a debt was paid off over the last 10, 7 and 2 bills, with the model weights shown.Debt Payoff CalculatorMonths and calendar time to clear a debt with a fixed monthly payment, optionally with payments that grow each month, plus the month-by-month walk.Discount CalculatorFinal price and savings from a discount percent or a known tag price, plus the reverse calculation from an amount already paid.Inflation CalculatorEquivalent value of an amount from an older year at a later year, compounding an annual inflation rate you supply, with a year-by-year walk.Loan Amortization ScheduleMonth-by-month or year-by-year amortisation schedule: interest split, principal repaid, and balance still owed.Mortgage Affordability CalculatorThe largest home price your income can carry: the payment, insurance and taxes at that price never exceed the cash you have spare each month.Mortgage CalculatorMonthly payment, lifetime interest and year-by-year balance for a home loan from price, down payment, term and interest rate.Percentage CalculatorPercent of a number, one number as a percent of another, and percent change between two values, with every formula spelled out.Rent vs Buy CalculatorRenting every month against buying once: break-even month, total cost over the period you own or rent, and the running comparison.Retirement Savings CalculatorCapital needed at retirement to withdraw a chosen income at a safe rate, against what steady savings and an expected return build by then.ROI CalculatorReturn on an investment from its initial and current value plus the holding period: ROI percent, annualized return, and the constant-rate path.Salary To Hourly CalculatorConvert between hourly, weekly, monthly and annual income in either direction, from hours per week and weeks worked per year.Sales Tax CalculatorAdd tax to a price: tax amount, total with tax, and the reverse pass that recovers the shelf price from an tax-inclusive total.Savings Goal CalculatorMonths and calendar time to reach a savings goal with the same deposit every month, with the yearly balance walk and the overshoot.Tip CalculatorGratuity and per-person split from a bill, tax you will also pay, and tip percent, with the share of the bill each line adds. Math & Calculators
Scientific, percentage and numeric calculators.
Age CalculatorExact age between two dates in years, months, and days, plus totals in months, weeks, and days, and a countdown table to the next five birthdays.GPA CalculatorAverage letter or numeric grades into a GPA: standard US 4.0 bands, UCAS points, or your own points map, with the grade distribution shown.Grade ConverterConvert a grade between percentage, US letter and GPA, UCAS points, German 0-15, and French out-of-20 scales, with the conversion math spelled out.Interest Rate CalculatorAnnual effective rate from observed growth, the Rule of 72 checked against exact doubling rates, and the rate needed to reach a goal over a horizon.Scientific CalculatorEvaluate arithmetic expressions step by step with a safe tokenizer and stack machine: powers, modulo, trig in degrees or radians, log, ln, sqrt and more. Conversion Tools
Units, currencies, files, formats and distances.
Audio ConverterConvert an uploaded audio file to WAV, MP3, OGG or FLAC with ffmpeg, showing duration, format, codec, sample rate and file size before and after.Currency ConverterConvert between major world currencies at live mid-market rates, with the rate, its timestamp, its source, and a rate table for every currency listed.Distance CalculatorGreat-circle and estimated road distance between two cities in kilometres and miles, plus door-to-door travel hours by car, train or plane at fixed average speeds.Image CompressorRe-encode an uploaded image as a JPG at a chosen encoder quality and optional maximum width, reporting original and compressed file sizes and the saving percentage.Image ConverterConvert an uploaded or linked image to PNG, JPG, WebP, TIFF or GIF at a chosen quality, with an optional narrower width.Image WatermarkerStamp a text or logo watermark on an uploaded image at a chosen corner or tiled across, with size and opacity controls, through ImageMagick.JSON to CSV ConverterTurn a JSON array of objects into a downloadable CSV file: every key becomes a column in order of first appearance, and values are quoted per the CSV rules.PDF To JPG ConverterRasterise the first pages of an uploaded PDF into standalone JPG or PNG images at a chosen DPI, reporting each page's pixel dimensions and file size.Speed ConverterConvert speed between kilometres per hour, miles per hour, metres per second, knots and feet per second, with the full conversion table and factor formula.Time Zone ConverterConvert a date and wall-clock time from any timezone or city to another zone, returning the target wall clock, the day change and the daylight-saving-correct GMT offsets for that exact date.Unit ConverterConvert any amount between units of length, weight, area, volume, data storage, duration, speed or temperature, with the factor table behind the number. Health & Fitness
Body, calorie, sleep and training calculators.
BMI CalculatorFind your body mass index from height and weight in metric or imperial units, see where you fall on the WHO seven-band scale, and read the weight range that a BMI of 18.5 to 25 implies at your height.BMR CalculatorEstimate your basal metabolic rate with the Mifflin–St Jeor and Harris–Benedict equations from age, height and weight, and see how the standard activity multipliers scale it.Body Fat Percentage CalculatorEstimate body fat percentage from neck, waist and height measurements (plus bust for women and optional weight), using the published Ideal Body Form equations and the ACE classification table.Calorie Burn CalculatorEstimate calories burned in a workout from activity, body weight (kg) and duration (minutes) using metabolic-equivalent (MET) values in kcal per kilogram of body mass per hour.Calorie CalculatorEstimate your daily calorie needs in kcal/day: basal metabolic rate by both Mifflin–St Jeor and Harris–Benedict formulas, maintenance and deficit targets scaled by activity multipliers (x1.0 to x1.8).Heart Rate Zone CalculatorFive training zones in bpm bands from your age or a measured maximum heart rate, with recovery, training and all-out ranges pulled out as cards.Pregnancy Due Date CalculatorExpected due date from the conception date plus a calendar-correct 280 days, with a gestation timeline in weeks and progress at any check date.Sleep Cycle CalculatorBedtimes that land on your alarm in whole ninety-minute sleep cycles, whole-night options listed best first, with next-day options when you name a target wake time.Sleep Quality CalculatorScores a night from hours slept, wake-ups and how the start of the night felt, on a 0-100 scale with a component breakdown and rating.Step Counter CalculatorSteps into distance and calories walked (or the reverse): the whole ladder between zero and your figure, plus stride, per-kilometre and per-1000-step figures.TDEE CalculatorEstimate your Total Daily Energy Expenditure from age, height, weight and activity level, starting from the Mifflin–St Jeor basal metabolic rate and the standard activity multipliers.Water Intake CalculatorDaily drinking-water target from body weight, weekly exercise hours and a climate band, split into a drink schedule across your waking hours.
Education & Learning
Grades, scores, word counts and study planning.
Text & Writing
Counters, cleaners, generators and text transforms.
Case ConverterRewrite text into UPPER, lower, Title, Sentence, camelCase, snake_case, kebab-case or aLtErNaTiNg case, with a before-and-after character comparison.Character CounterCounts characters with and without spaces, breaks the text down line by line, and separates graphemes from code points so accents and emoji count correctly.List AlphabetizerSorts a pasted list into A to Z or Z to A order, with case-insensitive and numeric-aware options so numbered items line up correctly.Lorem Ipsum GeneratorPlaceholder paragraphs of classic Lorem Ipsum: set the paragraph count and a minimum and maximum sentence count, with a seed so the same settings always give the same text.Markdown PreviewerPaste Markdown and see it rendered: headings, bold, italics, lists, tables, quotes, code and links, with pasted HTML kept safe.Remove Duplicate LinesDeletes repeated lines from a pasted list, keeps the first copy in its original order, and reports which lines were duplicated.Remove Special CharactersClean pasted text down to letters and digits, letters and spaces, printable characters only, or your own keep pattern; the removed count is reported.Reverse TextReverse any text by characters, words or lines. The character mode splits grapheme clusters, so emoji and accented letters move as one piece.Text ObfuscatorHide a phrase from casual reading with a deterministic transform: three leet levels, a ROT-13 style letter scramble, or an ASCII mirror flip.Text To SpeechHave your sentence read aloud in several languages: pick a voice and speed, download the spoken WAV, and it plays in any browser or phone.Word CounterCounts words, characters, sentences and paragraphs, ranks the most repeated words, and estimates the reading time of an essay or article. Developer & IT
Encoding, JSON, regex, colour and IP tools.
Base64 ConverterEncode text to Base64 or decode it back, with a strict decoder that rejects bad characters, broken padding and non-canonical endings.Binary Hex Decimal ConverterConvert any integer between binary, octal, decimal and hexadecimal with 0b, 0o and 0x prefixes and digit grouping, reporting bit length and two's-complement notes for negatives.Color PickerType any colour as hex, rgb(), hsl(), or a CSS name: get every other notation, WCAG contrast against black and white, and a shade ramp.CSS Gradient GeneratorBuild copy-paste CSS gradients from two or three hex colours: linear at any angle, radial or conic, with vendor-prefixed fallbacks and the same colours drawn in the other shapes.HTML FormatterReflow pasted or minified HTML onto indented lines: block tags one per line, void and inline tags respected, and <pre> blocks untouched.IP Address LookupParse a dotted-quad IPv4 address into octets, per-octet binary, a network-byte-order integer, hex, reserved or private range classification, and optional bitwise AND, OR, XOR or NOT with a mask.JSON Validator and FormatterValidate pasted JSON and pretty-print it with two-space indentation; invalid input gets the exact line and column where it first breaks, plus depth, node and key counts.Password GeneratorRandom passwords from a cryptographic source, with the character sets, look-alike and exclusion filters you choose, plus the entropy and crack-time maths.Password Strength CheckerScore a password 0 to 4 with every check shown: length, character variety, dictionary and keyboard patterns, counting runs and repeats, plus a crack-time estimate.QR Code GeneratorTurn text or a link into a QR code with qrencode: pick the error-correction level and the pixel size, preview it inline and download the vector SVG.Regex TesterRun a JavaScript regular expression against test text: every match with its position, and numbered or named capture groups as columns.URL Encoder and DecoderPercent-encode text for a URL component or a whole link (structure kept), or decode escapes back, with the table of every changed character and its code point. Games & Miscellaneous
Random numbers, word games and small amusements.
Anagram SolverUnscramble any letters into real words: every exact anagram that uses all of them, every shorter word buildable from the pool, and Scrabble scores per word.Countdown TimerCount down to a date or a length: time left at page load, weekday-by-weekday milestone dates, and a fresh tick on each refresh.Decision WheelSpin a wheel of up to twelve options: weights bend the slices, printed chances match, and a seed replays one landing.Random Number GeneratorFair integer draws from any range: any count, a no-repeats mode for lottery-style picks, and a seed that replays the exact result.White Noise GeneratorDownload a real .wav noise file built here in plain JavaScript: uniform white, gaussian or ramp noise at a chosen length and loudness, with a seed so the same settings always give the same file.Wordle SolverFeed the greens, yellows and greys of your Wordle guesses in and get the remaining candidates, ranked by how much each one still teaches.Zodiac Sign FinderYour sun sign from any date using the standard calendar table, with a warning when the date sits within a day of a sign boundary, plus element, modality and ruling planet facts.