Our Network

Free Online Tools

A growing network of free, fast, no-signup tools — calculators, developer utilities, text and media helpers, and handy references. Pick one and get to work.

53 toolsall free
50+
calculatorsdev toolsreferences

Calculators

Square Footage CalculatorCalculate the area of 31 different shapes — from simple rooms to gabled walls and irregular plots. Includes material-volume estimates for mulch, concrete and gravel, plus copy and PDF export.thesquarefootagecalculator.comPercentage CalculatorWork out percentages, percentage increases and decreases, and the difference between two numbers. Handy for discounts, tips, tax and everyday maths without the mental arithmetic.bestpercentagecalculator.netAge CalculatorFind an exact age in years, months, weeks and days from any birth date. Useful for birthdays, anniversaries, eligibility checks and counting down to a future date.theagecalculator.netHours CalculatorAdd up worked hours and time durations across a day or week, including breaks. Ideal for timesheets, payroll and tracking how long tasks really take.calculatehours.netEMI CalculatorCalculate loan EMIs with the total interest paid and a full month-by-month amortisation schedule. Compare home, car and personal loans before you commit.indiaemi.comMargin vs MarkupConvert between profit margin and markup, two figures that are easy to confuse but mean very different things. Price products correctly and see your true profit on every sale.marginvsmarkup.comDimensional Weight CalculatorWork out the dimensional (volumetric) weight couriers use to price parcels. Compare it against actual weight so you know which one you'll be charged for.dimweightcalc.comBox Volume CalculatorCalculate the volume of any box or carton in cubic inches, feet, centimetres or metres. Useful for shipping, storage planning and packing efficiently.boxvolumecalculator.comGirth CalculatorMeasure a package's girth — the distance around its thickest part — to check it against carrier size limits. Avoid surprise oversize fees before you ship.girthcalculator.comSolar CalculatorEstimate how many solar panels you need, the system size and your potential energy savings. A quick first step before getting professional quotes.prosolarcalc.toolsVoltage Drop CalculatorCalculate voltage drop across a wire run from length, gauge, load and material. Size cables correctly to stay within code and avoid underpowered circuits.voltdropcalc.comCalories CalculatorEstimate daily calorie needs, TDEE and macro targets from your age, weight, height and activity level. A practical starting point for any weight goal.calorieskit.comTotal Interest CalculatorSee the total interest you'll pay over the life of a loan and how it splits from the principal. Compare terms before you sign.totalinterestcalc.comAC Tonnage CalculatorEstimate the air-conditioner size in tons a room needs from its area and conditions. Avoid buying a unit that's too big or too small.actonnagecalc.comTank Volume CalculatorWork out the capacity of cylindrical, rectangular and oval tanks in litres or gallons, including partial fill levels. Handy for water, fuel and aquariums.tankvolumecalc.comCubic Yardage CalculatorConvert length, width and depth into cubic yards for concrete, mulch, gravel and soil. Order the right amount of material the first time.cubicyardage.comBMI & BMR CalculatorCalculate your Body Mass Index and Basal Metabolic Rate to gauge weight status and daily energy use. A quick, everyday health reference.bmibmrcalc.comSolar Battery Bank CalculatorSize an off-grid battery bank from your daily load, autonomy days and battery voltage. Plan reliable solar storage before you buy.solarbatterybankcalc.comFraction CalculatorAdd, subtract, multiply and divide fractions with clear step-by-step working and simplified results. Great for homework and quick checks.fractionsteps.comBackup Power CalculatorEstimate the generator or UPS size and runtime you need from your appliance load. Keep the essentials running through an outage.backuppowercalc.comStair CalculatorCalculate stair rise, run, stringer length and step count to code. Plan safe, comfortable stairs for decks, homes and basements.staircalculators.netConcrete Material CalculatorWork out concrete volume plus the cement, sand and aggregate needed for slabs, footings and columns. Cut waste and reorders.concretematerialcalc.comSIP CalculatorProject the future value of a systematic investment plan from your monthly amount, expected return and duration. See how regular investing compounds.sipcalculatorhub.comRoofing Material CalculatorEstimate shingles, underlayment and squares from your roof dimensions and pitch. Budget a re-roof accurately before ordering.roofingmaterialcalc.comGPA CalculatorCalculate your GPA from course grades and credit hours, on weighted or unweighted scales. Track academic progress with ease.gpacalculatorhq.comConstruction CalculatorsA hub of construction calculators for materials, areas and volumes across common building tasks. One stop for on-site estimating.constructioncalchq.comPool Volume CalculatorFind a swimming pool's volume in gallons or litres from its shape and dimensions. Dose chemicals and size pumps correctly.poolvolumecalc.com

Network

CIDR CalculatorTurn CIDR notation into usable subnet ranges, host counts and broadcast addresses. A fast reference for network engineers and anyone planning IP allocation.cidrcalculator.netSubnet Mask CalculatorCalculate subnet masks, wildcard masks and the number of usable hosts per subnet. Plan and document networks without manual binary maths.subnetmaskcalc.netInternet Speed TestMeasure your download, upload and ping speeds right in the browser. Check whether you're getting the connection you pay for.checkinternetspeed.toolsWhat Is My IPInstantly see your public IP address along with location and network details. Useful for troubleshooting and remote access.checkmyipnow.comWHOIS LookupLook up domain registration, ownership and expiry details from WHOIS records. Research domains and check availability fast.whoislookuppro.com

Developer

Base64 Encode / DecodeEncode text and files to Base64 or decode them back, right in your browser. Nothing is uploaded — everything runs locally for privacy.base64decode.toolsURL Encode / DecodePercent-encode URLs so special characters travel safely, or decode them back to readable text. Essential when building links, query strings and APIs.urlencodedecode.comUUID GeneratorGenerate and validate UUIDs in v1 and v4 formats, one at a time or in bulk. Perfect for database keys, test data and distributed systems.uuidcore.comJSON ToolsFormat, validate, minify and inspect JSON to catch errors and make it readable. A daily tool for developers working with APIs and config files.jsontools.toolsHash GeneratorGenerate MD5, SHA-1, SHA-2, SHA-3, BLAKE2, HMAC and password-KDF hashes from text or files. Useful for checksums, integrity checks and security work.hashgenerator.toolsEpoch Time ConverterConvert Unix timestamps to human-readable dates and back, across time zones. Indispensable when debugging logs, databases and APIs.epochtime.toolsCrontab Cheat SheetBuild cron schedules visually and decode existing crontab lines into plain English. Stop guessing what those five asterisks actually mean.crontabsheet.comRegex GuideTest regular expressions live against your own text and learn the syntax with clear examples. Build and debug patterns without trial-and-error in code.regexguide.comPassword StrengthCheck how strong a password is and how long it would take to crack. Get practical tips to make your logins genuinely secure.passwordstrength.netRemove MetadataStrip EXIF and hidden metadata — location, device, timestamps — from photos and files before sharing. Protect your privacy in seconds, entirely in-browser.removemetadata.toolsPDF ToolsMerge, split, rotate and reorder PDF files quickly and for free. Handle everyday document tasks without installing desktop software.corepdftools.comColor Code KitConvert colours between HEX, RGB, HSL and more, and explore palettes and contrast. A handy companion for designers and front-end developers.colorcodekit.comBarcode & QR GeneratorCreate barcodes and QR codes for URLs, text and products, then download them for print or web. Fast, free and no signup.barcodeandqr.comNumber to WordsConvert numbers into written words for cheques, invoices and legal documents. Supports currency and plain-number formats.numtotext.com

Text & Media

Pic ToolkitCrop, resize, compress and convert images between formats in your browser. Quick edits without opening heavy photo-editing software.pictoolkit.comWord CounterCount words, characters, sentences and paragraphs, with an estimated reading time. Great for essays, articles, social posts and meeting word limits.wordcounterfree.comText RepeaterRepeat or multiply any text a set number of times, with optional separators and line breaks. Saves tedious copy-pasting for testing and formatting.textrepeat.netCase ConverterConvert text between UPPERCASE, lowercase, Title Case, sentence case and more. Clean up headings, names and data in a couple of clicks.transformcase.com

Reference

Unit Cheat SheetA quick reference and converter for length, weight, volume, temperature and more. Find the conversion you need without digging through tables.unitcheatsheet.comWorld ClockSee the current time across world time zones at a glance. Schedule calls and track teammates, family and markets around the globe.clockwithus.comCooking Measurement ConverterConvert cooking measurements between cups, grams, ounces and millilitres, plus common ingredient weights. Cook any recipe without the guesswork.measurechef.com