Pick a utility.
Base64 Encoder / Decoder
Encode text to Base64 or decode a Base64 string back to UTF-8 text.
→URL Encoder / Decoder
Percent-encode URL components or decode an encoded URL back to plain text.
→ROT13 / Caesar Cipher
Encode/decode with ROT13 or arbitrary Caesar shift (0–25).
→Image to Base64
Convert any image (PNG, JPG, GIF, SVG, WebP) to a Base64 data URL.
→Hex ↔ ASCII / Text
Convert text to hexadecimal byte sequence and back. UTF-8 aware.
→JSON Formatter
Format, validate, and minify JSON with syntax error highlighting.
→Markdown Preview
Live preview Markdown as HTML. Side-by-side editor.
→Regex Tester
Test JavaScript regular expressions against input. See matches, groups, flags.
→Text Diff Checker
Compare two pieces of text line by line. See additions, removals, and changes.
→HTML / CSS / JS Minifier
Strip whitespace, comments, and shrink HTML, CSS, or JavaScript.
→Cron Expression Builder
Build cron expressions visually. Explains in plain English + shows next 5 runs.
→HTTP Status Codes
Look up any HTTP status code with description and common causes.
→JSON → TypeScript Types
Generate TypeScript interfaces from any JSON object or array.
→SQL Formatter
Format messy SQL queries with proper indentation and keyword case.
→Subnet / CIDR Calculator
Calculate network/broadcast/host range from a CIDR like 192.168.1.0/24.
→Markdown Table Generator
Build Markdown tables visually. Edit cells, set alignment, paste TSV/CSV.
→HTML Entities Encoder
Encode/decode HTML entities like & < > " and named entities.
→cURL → fetch() Converter
Paste a curl command, get equivalent JavaScript fetch() code.
→URL Parser
Break a URL into scheme, host, port, path, query, fragment.
→Query String Parser / Builder
Parse a query string into JSON, or build one from key/value pairs.
→Email Validator
Check email syntax. Single or bulk (one per line).
→User Agent Parser
Parse a User-Agent string into browser, OS, device, and version.
→MIME Type Lookup
Look up MIME type by file extension, or extension by MIME type.
→UUID Generator
Generate v4 (random) UUIDs in bulk. Copy single or batch.
→QR Code Generator
Generate QR codes for URLs, text, WiFi credentials, and more.
→Password Generator
Generate strong random passwords with customizable length and character sets.
→Lorem Ipsum Generator
Generate lorem ipsum placeholder text by paragraphs, sentences, or words.
→Random Number / Pick
Generate random numbers, pick from a list, shuffle items, flip a coin.
→Mock Data Generator
Generate fake names, emails, addresses, phone numbers as JSON or CSV.
→Color Converter
Convert between HEX, RGB, HSL, and HSV color formats. Includes a color picker.
→Timestamp Converter
Convert between Unix timestamp, ISO 8601, and human-readable date formats.
→Unit Converter
Convert length, weight, temperature, area, volume, speed, time, energy.
→Number Base Converter
Convert between binary, octal, decimal, and hexadecimal.
→Time Zone Converter
Convert any time to major world time zones (US, EU, Asia).
→JSON ↔ CSV Converter
Convert JSON array of objects to CSV, or CSV back to JSON.
→YAML ↔ JSON Converter
Convert between YAML and JSON. Auto-detects direction.
→Roman Numeral Converter
Convert between Roman numerals (I, V, X, L, C, D, M) and Arabic numbers.
→Percentage Calculator
Calculate percent of, percent change, percent off, and reverse percentages.
→Tip Calculator
Split a bill between any number of people with a configurable tip percentage.
→BMI Calculator
Body Mass Index — compute BMI and see WHO classification.
→Age Calculator
Calculate exact age in years, months, days, hours, minutes from a birthdate.
→Date Difference
How many days, weeks, months between two dates? Plus workdays.
→Working Days Calculator
Count business days between two dates, excluding weekends and optional holidays.
→Word & Character Counter
Count words, characters, sentences, paragraphs, and reading time.
→Slug Generator
Convert any text to a URL-safe slug (kebab-case, lowercase, ASCII).
→ASCII Art Text
Turn any text into stylized ASCII art (figlet-style banner).
→Case Converter
Convert between UPPER, lower, Title, camelCase, snake_case, kebab-case, etc.
→Sort & Dedupe Lines
Sort lines alphabetically, reverse, deduplicate, or filter empties.
→NATO Phonetic Alphabet
Spell text using the NATO phonetic alphabet (Alpha, Bravo, Charlie…).
→Find & Replace
Search and replace text. Optional case sensitivity, whole word, or regex.
→Strip HTML Tags
Remove HTML tags from text. Keeps text content, drops markup.
→Anagram Finder
Find anagrams of a word or letters. Filters by length, dictionary words.
→Reverse Text
Reverse characters, words, or lines. Mirror text via Unicode.
→CSS Box Shadow Generator
Visual box-shadow editor with live preview. Copy CSS instantly.
→CSS Gradient Generator
Build linear and radial CSS gradients with live preview. Copy the CSS.
→Color Contrast Checker
Check WCAG AA / AAA contrast ratio between two colors.
→Cubic Bézier Editor
Visual editor for CSS cubic-bezier easing curves. Live animation preview.
→px ↔ rem ↔ em
Convert between px, rem, em, %, pt, and vw/vh CSS units.
→Aspect Ratio Calculator
Calculate width or height given an aspect ratio (16:9, 4:3, 21:9, custom).
→Border Radius Generator
Generate CSS border-radius with per-corner control. Live preview.
→CSS Filter Generator
Combine blur, brightness, contrast, grayscale, sepia, hue-rotate, drop-shadow.
→CSS Clip-Path Generator
Visually create CSS clip-path shapes (polygons, circles, ellipses).
→Mortgage Calculator
Monthly mortgage payment with amortization breakdown. Principal, interest, taxes, insurance.
→Compound Interest Calculator
Future value with compound interest. Configurable contribution & compounding frequency.
→Loan Amortization
Monthly payment, total interest, and full payment schedule for any loan.
→Salary Converter
Convert between hourly, weekly, monthly, and annual pay.
→Retirement Calculator
401k / IRA / general retirement projection with employer match.
→Rent vs Buy Calculator
Compare 5/10/30-year total cost of renting versus buying a home.
→Mortgage Refinance Calculator
Should you refinance? Break-even months from rate drop + closing costs.
→Auto Loan Calculator
Car payment with down payment, trade-in, sales tax, and term.
→Credit Card Payoff Calculator
How long to pay off a credit card balance? Compare minimum vs aggressive payments.
→US Federal Income Tax Calculator
US federal income tax estimate for 2024 brackets. Single, married, HoH filing statuses.
→Inflation Calculator
What is $X worth in Y years given Z% inflation? Past and future value.
→Savings Goal Calculator
How long to reach a target? Or how much to save monthly?
→Statistics Calculator
Mean, median, mode, standard deviation, variance, range from a number list.
→Quadratic Equation Solver
Solve ax² + bx + c = 0 — real and complex roots.
→Triangle Calculator
Solve any triangle given 3 known parts (SSS, SAS, ASA, etc.).
→GCD / LCM Calculator
Find greatest common divisor and least common multiple of any numbers.
→Fraction Calculator
Add, subtract, multiply, divide fractions. Simplify to lowest terms.
→Modulo / Remainder Calculator
Compute a mod b — the remainder after division.
→Exponent & Root Calculator
Compute powers (a^b) and nth roots. Real and complex.
→Logarithm Calculator
Compute log_b(x) for any base. Natural log, log10, log2 presets.
→Slope Calculator
Slope and y-intercept from two points. Distance, midpoint included.
→Combinations & Permutations
Compute nCr (combinations) and nPr (permutations).
→Distance Formula Calculator
Distance between two points in 2D or 3D. Includes midpoint and angle.
→TDEE / Calorie Calculator
Calculate Total Daily Energy Expenditure based on age, weight, activity.
→Body Fat Calculator
Estimate body fat % using the US Navy circumference method.
→Running Pace Calculator
Convert pace ↔ speed. Predict race finish times at any distance.
→One Rep Max (1RM)
Estimate your 1RM from a heavier set. Includes Epley, Brzycki, Lombardi formulas.
→Macro Calculator
Split calorie target into protein, carbs, and fat by goal (cut, bulk, keto).
→Pregnancy Due Date
Estimate due date and current week from last menstrual period or conception date.
→Water Intake Calculator
Daily water intake based on weight, activity, climate.
→Heart Rate Zones
Training heart rate zones from age and resting HR.
→Built for people who don't
want their data sold.
Client-side only
Every tool runs in your browser. Inputs never touch a server. We literally can't see what you put in.
Instantly fast
Each tool is one focused page. No 5 MB JavaScript bundle. Loads in under a second on any device.
No signup walls
No accounts. No rate limits. No "sign in to use this feature" gates. Use as much as you want.
Honest scope
96 tools people reach for daily. Not 200 listings padding the catalog.
Why "1vw"?
In CSS, 1vw is a viewport unit meaning "1% of the viewport width." Small unit. Small tools. The domain is a wink to anyone who's written CSS — if you got it, you're in the right place.
Free forever.
Display advertising on category and home pages keeps the lights on. No ads inside the tools themselves. If an ad ever interrupts a workflow, email hello@1vw.net — we'll fix it.