Lumina
Calculators that feel alive
Thirty-plus everyday tools — weather, maps, math, money, dates, and more — fast, clear, and built for search.
Bright tools
Pick a calculator. Every page is optimized for discovery in your language.
308 tools
Math
28Probability Calculator
Compute coin flips, dice odds, combinations, and conditional probability with clear formulas.
OpenPercentage Calculator
Find percent of a number, percent change, what percent X is of Y, and reverse percentages.
OpenArithmetic Calculator
Add, subtract, multiply, and divide with precise decimal results.
OpenUnit Converter
Convert length, mass, temperature, volume, area, speed, data, and time units.
OpenMath & Scientific Calculator
Scientific keypad, quadratic equations, GCD/LCM, factorial, primes, and basic statistics.
OpenBase Converter
Convert numbers between binary, octal, decimal, and hexadecimal.
OpenRoman Numerals
Convert between Arabic numbers and Roman numerals (1–3999).
OpenSubnet Calculator
Calculate IPv4 network, mask, broadcast, and hosts.
OpenPX REM Converter
Convert px, rem, and em with a custom base size.
OpenFile Size Converter
Convert bytes through TB without rounding surprises.
OpenBitrate Calculator
Estimate a file size from bitrate and duration.
OpenGPA Calculator
Calculate a 4.0 GPA from credits and letter grades.
OpenTriangle Helper
Check triangle sides, area, perimeter, and angles.
OpenKitchen Converter
Kitchen Converter — free browser tool.
OpenFrames Per Second Calculator
Frames Per Second Calculator — free browser tool.
OpenLottery Number Generator
Lottery Number Generator — free browser tool.
OpenRule of 72 Calculator
Rule of 72 Calculator — free browser tool.
OpenDensity Calculator
Compute density from mass and volume, or solve for the missing value.
OpenSlope & Grade
Rise/run slope, percent grade, and angle from two points or rise and run.
OpenPercent Change
Percent increase or decrease between an old and new value.
OpenSpeed · Distance · Time
Solve speed, distance, or time when two values are known.
OpenArea Unit Converter
Convert between m², ft², acres, and pyeong.
OpenGCD & LCM
Greatest common divisor and least common multiple of two integers.
OpenWeighted Average
Weighted mean from value·weight pairs.
Open2D Midpoint & Distance
Midpoint and Euclidean distance between two points.
OpenSignificant Figures
Round a number to N significant figures.
OpenSimplify Ratio
Reduce a:b to lowest terms using GCD.
OpenRecipe Scaler
Scale ingredient amounts by servings factor.
OpenMoney
38Currency Converter
Convert currencies with live reference rates from multiple free FX sources.
OpenFinance & BMI
Loan payments, compound interest, tip, discount, and BMI.
OpenFuel Cost Calculator
Estimate trip fuel cost from distance, efficiency, and price per liter/gallon.
OpenSalary Converter
Convert between hourly, daily, weekly, monthly, and yearly pay.
OpenCrypto Prices
Check major crypto prices in USD, EUR, and KRW.
OpenIBAN Validator
Format and validate IBANs with the mod-97 check.
OpenROI Calculator
Calculate profit and return on investment percentage.
OpenAmortization Calculator
See payment totals and the first year of a loan schedule.
OpenTip & Bill Split
Calculate a tip and split a bill between people.
OpenVat
A free browser-based Lumina tool.
OpenMarkup
A free browser-based Lumina tool.
OpenCAGR Calculator
CAGR Calculator — free browser tool.
OpenTest Card Validator
Test Card Validator — free browser tool.
Open50/30/20 Budget
50/30/20 Budget — free browser tool.
OpenInflation Adjuster
Adjust an amount for inflation over years at a yearly rate.
OpenShipping Weight
Shipping Weight — free browser tool.
OpenSimple Invoice
Simple Invoice — free browser tool.
OpenCompound Interest
Project growth with principal, rate, compounding frequency, and optional deposits.
OpenSimple Interest
Calculate simple interest, total amount, and effective return over time.
OpenInsurance Estimate
Educational term-life coverage and premium rule-of-thumb estimates.
OpenLoan Payoff
See how extra monthly payments shorten a loan and cut interest.
OpenBreak-Even Point
Find units and revenue needed to cover fixed and variable costs.
OpenSales Discount
Sale price after percent off, optional tax, and amount saved.
OpenUnit Price Compare
Compare two packs by price per unit to spot the better deal.
OpenSavings Goal
Months to reach a goal with monthly deposits and optional interest.
OpenSalary ↔ Hourly
Convert annual salary to hourly/weekly pay or reverse.
OpenElectricity Cost
Estimate bill from kWh usage or device watts and hours.
OpenTip Calculator
Tip amount and total from bill and tip percentage.
OpenStacked Discounts
Apply two successive percent discounts and see the true total off.
OpenInflation Adjuster
Adjust an amount for inflation over years at a yearly rate.
OpenFIRE Number
Rough FI nest egg from annual spending (25× / 4% rule).
OpenCommute Cost
Weekly and yearly commute fuel cost from distance and fuel price.
OpenPay Period Converter
Convert annual salary across weekly, biweekly, semimonthly, monthly.
OpenNet Worth Snapshot
Assets minus liabilities for a quick net-worth total.
OpenDay Rate Calculator
Freelance day rate from target annual income and billable days.
OpenLease vs Buy
Rough 3-year cost comparison of leasing versus buying.
OpenCash Denomination Break
Break an amount into bills and coins for a till.
OpenProrated Bill
Partial-period charge for rent or subscriptions.
OpenTime
21Date Calculator
Date difference, age, and add or subtract days, weeks, months, or years.
OpenTimezone Converter
Convert a date and time between world time zones.
OpenUnix Timestamp
Convert between Unix epoch seconds/ms and human-readable dates.
OpenTimer & Stopwatch
Countdown timer and stopwatch with lap times in your browser.
OpenPublic Holidays
Find public holidays by country and year.
OpenMeeting Time Planner
Compare the current time across cities and zones.
OpenCountdown
Count down to a future date and time.
OpenSleep Cycle Planner
Find bedtime or wake times based on 90-minute cycles.
OpenWorld Clock
Live clocks for major cities, updated every second.
OpenPomodoro Timer
Focus for 25 minutes, then take a five-minute break.
OpenDetailed Age Calculator
Calculate age in years, months, and days.
OpenIcs
A free browser-based Lumina tool.
OpenWorkdays
A free browser-based Lumina tool.
OpenWeeknum
A free browser-based Lumina tool.
OpenMetronome
A free browser-based Lumina tool.
OpenTime Add & Subtract
Time Add & Subtract — free browser tool.
OpenFrames & Timecode
Frames & Timecode — free browser tool.
OpenRelative Time
Relative Time — free browser tool.
OpenDay of Year
Day-of-year number and days remaining in the year.
OpenAdd / Subtract Dates
Add or subtract days, weeks, or months from a date.
OpenPrecise Age (Y/M/D)
Exact age in years, months, and days from a birth date.
OpenGeo
11Coordinate Calculator
Great-circle distance, bearing, midpoint, and DMS ↔ decimal conversion.
OpenWeather Forecast
Free 7-day weather forecast by city using Open-Meteo — no API key needed.
OpenMaps Shortcuts
Build Google Maps search, directions, Street View, and pin links — plus free place search.
OpenIP Lookup
Look up your public IP or any IPv4/IPv6 — city, ISP, and timezone (free).
OpenAir Quality
Check AQI and particle levels by city.
OpenRecent Earthquakes
Browse USGS magnitude 2.5+ events from the last day.
OpenCountry Lookup
Find a country’s capital, population, currencies, and languages.
OpenMap Scale
Convert map distance to real-world distance using a ratio scale.
OpenWind Chill
Apparent temperature from air temperature and wind speed.
OpenHeat Index
Apparent temperature from air temperature and relative humidity.
OpenDew Point
Estimate dew point from temperature and relative humidity.
OpenEngineering
21Angle
A free browser-based Lumina tool.
OpenOhm's Law Calculator
Solve voltage, current, resistance, or power from any two known values.
OpenConcrete Volume
Estimate slab or footing concrete volume in m³ and bags.
OpenGear Ratio
Compute gear ratio, output RPM, and torque trade-offs.
OpenWire Gauge (AWG)
Educational ampacity guide for copper AWG wire sizes.
OpenHeating BTU Estimate
Rough room heating load from area, ceiling height, and climate.
OpenPaint Coverage
Wall paint litres from room dimensions and coats.
OpenTile Calculator
Floor or wall tiles needed with waste allowance.
OpenStair Rise & Run
Step count, riser height, and tread depth from total rise.
OpenGravel / Mulch Volume
Bulk material volume and bags from area and depth.
OpenFence Posts
Post count and panel spans for a straight fence run.
OpenRoof Pitch
Pitch ratio, degrees, and rafter length from rise and run.
OpenWallpaper Rolls
Estimate wallpaper rolls from wall area and roll coverage.
OpenPool Volume
Rectangular pool volume in litres and gallons.
OpenBoard Feet
Lumber board feet from thickness, width, length, and count.
OpenDimensional Weight
Courier dimensional weight from L×W×H and divisor.
OpenCarpet / Flooring
Flooring area with waste allowance in m² and rolls.
OpenDrywall Sheets
How many drywall sheets for a wall area with waste.
OpenTorque Units
Convert newton-metres ↔ pound-feet.
OpenTire Size Geometry
Overall diameter, circumference, and revs/km from tire code.
OpenPacking Volume
Box fill % from item and box dimensions.
OpenAstronomy
7Sunrise & Sunset
Find today’s sunrise and sunset by city.
OpenMoon
A free browser-based Lumina tool.
OpenZodiac Sign
Zodiac Sign — free browser tool.
OpenJulian Day
Convert calendar dates to Julian Day Number and modified Julian day.
OpenPlanet Distances
Solar-system planet distances, orbital periods, and light-travel times.
OpenSidereal Time
Approximate local mean sidereal time from longitude and UTC.
OpenStar Magnitude
Convert apparent magnitude differences into brightness ratios.
OpenPDF & ZIP
6Merge PDF
Combine multiple PDF files into one, entirely in your browser.
OpenSplit PDF
Extract a page range or split every page into separate PDFs.
OpenPDF Watermark Tools
Remove annotation/stamp watermarks, or add a simple text watermark.
OpenUnlock PDF
Open a password-protected PDF with a known password, or recover yours with wordlist + charset brute-force — all in the browser.
OpenUnlock ZIP
Open a password-protected ZIP with a known password, or recover yours with wordlist + charset brute-force — all in the browser.
OpenRotate PDF Pages
Rotate all pages 90°, 180°, or 270° and download the result.
OpenText
42Text to Speech
Read text aloud in many languages using your browser voices.
OpenText Tools
Count words and characters, change case, make slugs, and reverse text.
OpenJSON Formatter
Validate, pretty-print, and minify JSON in the browser.
OpenURL Tools
Encode, decode, and parse URLs and query strings.
OpenLorem Ipsum Generator
Generate placeholder paragraphs, sentences, or words for layouts.
OpenMarkdown Preview
Live preview of Markdown with headings, lists, links, and code.
OpenRegex Tester
Test JavaScript regular expressions with live match highlighting.
OpenMorse Code
Encode and decode Morse code for letters, digits, and spaces.
OpenText Diff
Compare two texts line-by-line and highlight additions and removals.
OpenASCII / Unicode Codes
Convert text to character codes and codes back to text.
OpenHTML Entity Encoder
Encode or decode HTML entities safely.
OpenCSV JSON Converter
Convert CSV rows to JSON or JSON arrays to CSV.
OpenSEO Meta Tag Generator
Generate title, description, and Open Graph HTML.
OpenCaesar Cipher
Encode text with Caesar shift or ROT13.
OpenNATO Alphabet
Spell text with the NATO phonetic alphabet.
OpenReading Time Calculator
Estimate reading time from word count and speed.
OpenDictionary
Look up English definitions and pronunciation.
OpenWikipedia Summary
Read a short Wikipedia summary in the selected language.
OpenRandom Quote
Get a fresh quotation when the service is available.
OpenFindreplace
A free browser-based Lumina tool.
OpenSortlines
A free browser-based Lumina tool.
OpenWordfreq
A free browser-based Lumina tool.
OpenNumwords
A free browser-based Lumina tool.
OpenIsbn
A free browser-based Lumina tool.
OpenPassphrase
A free browser-based Lumina tool.
OpenTablemd
A free browser-based Lumina tool.
OpenEdit Distance
Edit Distance — free browser tool.
OpenHangul Jamo Tool
Hangul Jamo Tool — free browser tool.
OpenList Operations
List Operations — free browser tool.
OpenEmail Extractor
Email Extractor — free browser tool.
OpenEmail Validator
Email Validator — free browser tool.
OpenSlug Generator
Slug Generator — free browser tool.
OpenEmoji Remover
Emoji Remover — free browser tool.
OpenWhitespace Cleaner
Whitespace Cleaner — free browser tool.
OpenCharacter Diff
Character Diff — free browser tool.
OpenAnagram Checker
Anagram Checker — free browser tool.
OpenPalindrome Checker
Palindrome Checker — free browser tool.
OpenSoundex Name Code
Soundex Name Code — free browser tool.
OpenBraille Converter
Braille Converter — free browser tool.
OpenVigenère Cipher
Vigenère Cipher — free browser tool.
OpenASCII Art Banner
ASCII Art Banner — free browser tool.
OpenMarkdown Cheat Sheet
Markdown Cheat Sheet — free browser tool.
OpenDesign
30Color Converter
Convert colors between HEX, RGB, and HSL with a live preview.
OpenQR Code Generator
Create QR codes from text or URLs and download the image.
OpenColor Contrast (WCAG)
Check WCAG AA/AAA contrast ratio between foreground and background colors.
OpenAspect Ratio Calculator
Find matching width or height for ratios like 16:9, 4:3, and custom.
OpenCSS Gradient Builder
Build a CSS linear gradient with a live preview.
OpenColor Palette Generator
Explore complementary, analogous, and triadic colors.
OpenScreeninfo
A free browser-based Lumina tool.
OpenBoxshadow
A free browser-based Lumina tool.
OpenBorderradius
A free browser-based Lumina tool.
OpenImgbase64
A free browser-based Lumina tool.
OpenImgresize
A free browser-based Lumina tool.
OpenFavicongen
A free browser-based Lumina tool.
OpenClampcss
A free browser-based Lumina tool.
OpenColor Eyedropper
Color Eyedropper — free browser tool.
OpenGlassmorphism CSS
Glassmorphism CSS — free browser tool.
OpenFlexbox Playground
Flexbox Playground — free browser tool.
OpenCSS Grid Generator
CSS Grid Generator — free browser tool.
OpenPaper Size Converter
Paper Size Converter — free browser tool.
OpenColor Adjuster
Color Adjuster — free browser tool.
OpenWhiteboard
Whiteboard — free browser tool.
OpenPrint DPI Calculator
Print DPI Calculator — free browser tool.
OpenColor Blindness Simulator
Color Blindness Simulator — free browser tool.
OpenCSS Color Name Finder
CSS Color Name Finder — free browser tool.
OpenRandom Color Palette
Random Color Palette — free browser tool.
OpenTint & Shade Scale
Tint & Shade Scale — free browser tool.
OpenCSS Filter Playground
CSS Filter Playground — free browser tool.
OpenNeumorphism Generator
Neumorphism Generator — free browser tool.
OpenButton CSS Generator
Button CSS Generator — free browser tool.
OpenCSS Animation Generator
CSS Animation Generator — free browser tool.
OpenCentering CSS Recipes
Centering CSS Recipes — free browser tool.
OpenHealth
30TDEE Calculator
Estimate BMR and daily energy needs.
OpenRunning Pace Calculator
Find pace or race time from distance and time.
OpenOne-Rep Max (1RM)
Estimate one-rep max from weight and reps (Epley).
OpenBreathing Guide
Breathing Guide — free browser tool.
OpenBMI Calculator
Body mass index from height and weight with category guidance.
OpenBody Fat Estimate
US Navy circumference method estimate of body fat percentage.
OpenPregnancy Due Date
Estimated due date and week from last menstrual period (LMP).
OpenOvulation Window
Approximate fertile window from cycle length and last period.
OpenDaily Water Intake
Rough daily water target from body weight and activity.
OpenCalories Burned
Estimate walking or running calories from weight, distance, and pace.
OpenDaily Protein Need
Estimate daily protein grams from body weight and activity.
OpenLean Body Mass
Boer formula lean body mass from sex, height, and weight.
OpenCaffeine Half-Life
Estimate remaining caffeine after hours using a half-life model.
OpenOne-Rep Max (1RM)
Estimate one-rep max from weight and reps (Epley).
OpenHeart Rate Zones
Training zones from age using % of max heart rate.
OpenIdeal Body Weight
Devine formula ideal weight from sex and height.
OpenMacro Split
Split daily calories into protein, carbs, and fat grams.
OpenWaist–Hip Ratio
Waist-to-hip ratio with simple category guidance.
OpenBody Surface Area (BSA)
Mosteller body surface area from height and weight.
OpenPonderal Index
Rohrer ponderal index — mass relative to height cubed.
OpenA Body Shape Index (ABSI)
Waist-based shape index using height, weight, and waist.
OpenBlood Pressure Category
Educational AHA-style category from systolic and diastolic.
OpenCholesterol Ratios
TC/HDL and LDL/HDL ratios with simple guidance bands.
OpenA1C ↔ Average Glucose
Convert HbA1c (%) to estimated average glucose and back.
OpenBasal Metabolic Rate (BMR)
Mifflin–St Jeor resting calorie estimate from sex, age, height, weight.
OpenVO₂ Max Estimate
Rough VO₂ max from age, sex, and resting heart rate.
OpenPregnancy Weight Gain
IOM-style total gain guidance from pre-pregnancy BMI.
OpenBAC Estimate
Widmark-style blood alcohol estimate — educational only.
OpenFat-Free Mass Index
FFMI from weight, height, and body-fat %.
OpenBody Frame Size
Small/medium/large frame from height and wrist circumference.
OpenDev
44Password Generator
Generate strong random passwords with length and character options.
OpenHash & UUID
SHA digests with Web Crypto and UUID v4 generation.
OpenRandom Tools
Random numbers, dice, coin flips, and pick-from-list.
OpenJWT Decoder
Decode JSON Web Token header and payload locally — no signature verify.
OpenBase64 Encoder
Encode or decode Base64 text locally.
OpenCron Expression Explainer
Explain a standard five-field cron schedule.
OpenvCard Generator
Build a vCard 3.0 contact and download a .vcf.
OpenWi-Fi QR Generator
Create a QR code for joining a Wi-Fi network.
OpenUsername Generator
Create quick username ideas from a seed word.
OpenShort ID Generator
Generate compact random IDs for labels and prototypes.
OpenChmod
A free browser-based Lumina tool.
OpenMime
A free browser-based Lumina tool.
OpenHttpstatus
A free browser-based Lumina tool.
OpenDns
A free browser-based Lumina tool.
OpenUseragent
A free browser-based Lumina tool.
OpenXmlfmt
A free browser-based Lumina tool.
OpenYamljson
A free browser-based Lumina tool.
OpenUlid
A free browser-based Lumina tool.
OpenCookiestr
A free browser-based Lumina tool.
OpenJsonpath
A free browser-based Lumina tool.
OpenJSON to TypeScript
JSON to TypeScript — free browser tool.
OpenCSV to SQL
CSV to SQL — free browser tool.
OpenFake Data Generator
Fake Data Generator — free browser tool.
OpenCORS Header Generator
CORS Header Generator — free browser tool.
OpenSemVer Bump Tool
SemVer Bump Tool — free browser tool.
OpenConventional Commit Builder
Conventional Commit Builder — free browser tool.
OpenGlob to RegExp
Glob to RegExp — free browser tool.
OpenPunycode Converter
Punycode Converter — free browser tool.
OpenUnicode Inspector
Unicode Inspector — free browser tool.
OpenText to Binary
Text to Binary — free browser tool.
OpenKeyboard Event Tester
Keyboard Event Tester — free browser tool.
OpenStorage Quota Checker
Storage Quota Checker — free browser tool.
OpenPassword Strength Check
Password Strength Check — free browser tool.
OpenPwned Password Check
Pwned Password Check — free browser tool.
OpenUnsigned JWT Builder
Unsigned JWT Builder — free browser tool.
OpenSQL Formatter
SQL Formatter — free browser tool.
Open.env Parser
.env Parser — free browser tool.
OpenDockerfile Snippets
Dockerfile Snippets — free browser tool.
OpenDocker Compose Generator
Docker Compose Generator — free browser tool.
OpenJSON Diff
JSON Diff — free browser tool.
OpenCSV Statistics
CSV Statistics — free browser tool.
OpenGravatar URL
Gravatar URL — free browser tool.
OpenSecurity Headers
Security Headers — free browser tool.
OpenBasic Auth Header
Basic Auth Header — free browser tool.
OpenWeb
30Major Sites Hub
Browse selected major websites by category.
OpenUtm
A free browser-based Lumina tool.
OpenShare
A free browser-based Lumina tool.
OpenMailto
A free browser-based Lumina tool.
OpenRobots
A free browser-based Lumina tool.
OpenHtaccess
A free browser-based Lumina tool.
OpenNotepad
A free browser-based Lumina tool.
OpenChecklist
A free browser-based Lumina tool.
OpenMediaquery
A free browser-based Lumina tool.
OpenSeolength
A free browser-based Lumina tool.
OpenSocialcount
A free browser-based Lumina tool.
Open.gitignore Builder
.gitignore Builder — free browser tool.
OpenNginx Redirect Generator
Nginx Redirect Generator — free browser tool.
OpenSitemap XML Builder
Sitemap XML Builder — free browser tool.
OpenPWA Manifest Generator
PWA Manifest Generator — free browser tool.
OpenOpen Graph Tag Generator
Open Graph Tag Generator — free browser tool.
OpenJSON-LD Generator
JSON-LD Generator — free browser tool.
OpenURL Extractor
URL Extractor — free browser tool.
OpenPlaceholder Image URL
Placeholder Image URL — free browser tool.
OpenWayback Link Builder
Wayback Link Builder — free browser tool.
OpenCanonical URL Cleaner
Canonical URL Cleaner — free browser tool.
OpenHreflang Tag Generator
Hreflang Tag Generator — free browser tool.
OpenHTML Snippets
HTML Snippets — free browser tool.
OpenCSS Cheat Sheet
CSS Cheat Sheet — free browser tool.
OpenGit Cheat Sheet
Git Cheat Sheet — free browser tool.
OpenLinux CLI Cheat Sheet
Linux CLI Cheat Sheet — free browser tool.
OpenKeyboard Shortcuts
Keyboard Shortcuts — free browser tool.
OpenRandom Team Splitter
Random Team Splitter — free browser tool.
OpenWeighted Random Picker
Weighted Random Picker — free browser tool.
OpenLocal Scoreboard
Local Scoreboard — free browser tool.
OpenNo tools match.