Free tools.
Other free, no-signup, in-browser tools we like — calculators, converters and utilities across 52 sites.
Calculators & Measurement
Square Footage Calculator
thesquarefootagecalculator.com
Work out the area of rooms, walls, floors and odd shapes — rectangles, circles, triangles, L- and U-shapes — with cost-per-square-foot estimates for flooring and paint.
FREEPercentage Calculator
bestpercentagecalculator.net
Every percentage problem in one place: percent of a number, percentage increase or decrease, discounts, tips and the difference between two values.
FREEAge Calculator
theagecalculator.net
Exact age in years, months and days, birthday countdowns, date-to-date math, and a birthday twin finder — all from a date of birth.
FREEHours Calculator
calculatehours.net
Add up time cards, find hours between two clock times, and convert decimal hours for payroll — built for shift work and invoicing.
FREEBox Volume Calculator
boxvolumecalculator.com
Carton and crate volume in cubic inches, feet or metres, with packing and shipping context for moving boxes and freight.
FREEGirth Calculator
girthcalculator.com
Parcel girth (length + 2×width + 2×height) against USPS, UPS and FedEx limits, so a package never bounces at the counter.
FREEDimensional Weight Calculator
dimweightcalc.com
Carrier dim-weight pricing decoded: enter box dimensions and see the billable weight for 17 carriers, including the rounding rules they actually use.
FREEUnit Cheat Sheet
unitcheatsheet.com
A fast conversion reference covering length, weight, volume, temperature, pressure and more — the lookup table for everything.
FREEAC Tonnage Calculator
actonnagecalc.com
Size air-conditioning capacity from room dimensions and climate, with separate US and India modes, ZIP/PIN climate lookup and per-space guides.
FREECubic Yardage Calculator
cubicyardage.com
Cubic yards of concrete, gravel, mulch, topsoil or sand from simple dimensions, so you order the right load and never pay for a second delivery.
FREEPool Volume Calculator
poolvolumecalc.com
Swimming-pool water volume in gallons or litres for rectangular, round, oval and irregular shapes — the number behind dosing chemicals, heating and refills.
FREEStair Calculator
staircalculators.net
Stair rise, run, stringer length and step count worked to building-code limits, so a staircase is safe and comfortable before any timber is cut.
FREEConcrete Material Calculator
concretematerialcalc.com
Concrete, cement, sand and aggregate quantities for slabs, footings and columns, with the mix ratio, so you buy the right number of bags.
FREERoofing Material Calculator
roofingmaterialcalc.com
Shingles, underlayment and materials estimated from roof area and pitch, with waste factored in to budget a re-roof accurately.
FREEConstruction Calculators
constructioncalchq.com
A hub of construction calculators for materials, areas, volumes and project estimates — the everyday jobsite math for builders and DIYers.
FREECooking Measurement Converter
measurechef.com
Convert cups, grams, ounces, millilitres and spoons for any recipe, and scale servings up or down without the usual kitchen guesswork.
FREEFraction Calculator
fractionsteps.com
Add, subtract, multiply and divide fractions and mixed numbers with every step shown — for homework, recipes and workshop measurements.
FREEGPA Calculator
gpacalculatorhq.com
Grade point average and cumulative CGPA from letter grades and credit hours across common scales, to track standing and plan the marks you need.
Money & Finance
Margin vs Markup Calculator
marginvsmarkup.com
The pricing math both directions — margin to markup and back — with the tables and formulas that keep retail pricing honest.
FREETotal Interest Calculator
totalinterestcalc.com
See the lifetime interest on a mortgage or loan, not just the payment: amortization breakdowns with live market rate context.
FREEIndia EMI Calculator
indiaemi.com
Loan EMIs for the Indian market: home, car, personal and credit-card EMIs with GST, advance/arrears modes and full schedules.
FREESolar Calculator
prosolarcalc.com
Size a solar system from your usage and location, then see panel count, inverter sizing and payback estimates.
FREESIP Calculator
sipcalculatorhub.com
Project the maturity value of a mutual-fund SIP from your monthly contribution, expected return and tenure, with optional annual step-ups.
Developer Tools
JSON Tools
jsontools.tools
Format, validate, repair and explore JSON in the browser — including a repair engine that fixes 23 kinds of broken JSON and a collapsible tree view.
FREEHash Generator
hashgenerator.tools
MD5, SHA-1/256/512 and HMAC hashes computed entirely in your browser — nothing is uploaded anywhere.
FREEBase64 Decode
base64decode.tools
Encode and decode Base64 text and files locally, with URL-safe variants and binary handling.
FREEURL Encode/Decode
urlencodedecode.com
Escape and unescape URLs and query strings, with component-vs-full-URL modes and common pitfall notes.
FREEUUID Generator
www.uuidcore.com
Generate v4 UUIDs one at a time or in bulk, copy-ready for databases, tests and APIs.
FREEEpoch Time Tools
epochtime.tools
Unix timestamps both directions — epoch to human date and back — with timezone handling and code snippets per language.
FREECrontab Sheet
crontabsheet.com
Cron syntax explained, tested and built visually: a reference sheet plus an expression builder with plain-English readouts.
FREERegex Guide
regexguide.com
Regular expressions from first match to mastery: a live tester, a pattern library and a 377-page learning reference.
FREECIDR Calculator
cidrcalculator.net
Subnet a network in CIDR notation: address ranges, usable hosts, wildcard masks and split/merge planning.
FREESubnet Mask Calculator
subnetmaskcalc.net
IPv4 subnetting worked out step by step, with code examples in six languages and a full FAQ for networking students.
FREEInternet Speed Test
checkinternetspeed.tools
Measure download, upload and ping speed straight in the browser, with a clear read on latency and throughput before you call the provider.
FREEWhat Is My IP
checkmyipnow.com
See your public IP address with the location, ISP and browser details websites can detect — handy for VPN checks and network troubleshooting.
FREEWHOIS Lookup
whoislookuppro.com
Look up domain registration, ownership, expiry dates and DNS records for any site — for buying domains and tracking your own renewals.
Text & Writing
Word Counter
wordcounterfree.com
Words, characters, sentences, paragraphs and reading time as you type — with keyword density for writers and students.
FREETransform Case
transformcase.com
Convert text between UPPER, lower, Title, camelCase, snake_case and more, plus a set of cleanup tools for messy text.
FREEText Repeat
textrepeat.net
Repeat any text n times with separators and counters — handy for test data, printables and bulk lists.
FREEPassword Strength Checker
passwordstrength.net
Test a passphrase's strength entirely on your device — entropy, crack-time estimates and concrete suggestions, never transmitted.
FREENumber to Words
numtotext.com
Spell numbers out in words for cheques, invoices and contracts, with currency formatting and large figures handled so the words match the digits.
Files, Images & Color
Core PDF Tools
corepdftools.com
Merge, split, compress, rotate and protect PDFs entirely in the browser — your documents never leave your machine.
FREERemove Metadata
removemetadata.tools
Strip EXIF, GPS and document metadata from photos, PDFs, Office files, audio and video before you share them — privacy-first and fully client-side.
FREEPic Toolkit
pictoolkit.com
Browser-based image utilities: resize, crop, convert and tweak pictures without uploading them to a server.
FREEColor Code Kit
colorcodekit.com
Palettes, gradients, named colors and conversions between HEX, RGB, HSL and OKLCH — plus dark-mode and brand-color tools for designers.
FREEBarcode & QR Generator
barcodeandqr.com
Generate QR codes and every common barcode symbology with print-ready PDF export — verified by real decode testing.
Health, Time & More
Calories Kit
calorieskit.com
Calorie, macro and body-composition calculators — TDEE, protein targets, meal planning tools — with a cited methodology behind every formula.
FREEVoltage Drop Calculator
voltdropcalc.com
NEC-based wire sizing and voltage drop for electricians: 18 calculators, conductor tables and inspector-ready PDF reports.
FREEClock With Us
clockwithus.com
World clocks, timers and time-zone views for coordinating across cities.
FREEBMI & BMR Calculator
bmibmrcalc.com
Body mass index and basal metabolic rate from height, weight, age and sex — where you sit on the scale and the calories you burn at rest.
FREESolar Battery Bank Calculator
solarbatterybankcalc.com
Size a solar battery bank from daily load, days of autonomy and depth of discharge — the storage math for off-grid and backup systems.
FREEBackup Power Calculator
backuppowercalc.com
Size a generator or battery backup from appliance wattage and the runtime you need, so you plan for outages without over- or under-buying.