Free Web Tools for Everyone
Fast, free utilities that run entirely in your browser. No account needed, no data uploaded, no strings attached.
JSON & Data (5)
JSON to Excel
Convert JSON arrays or objects into a downloadable .xlsx spreadsheet instantly.
JSON Formatter
Format, validate, and minify JSON instantly in your browser. Real-time error detection.
CSV ↔ JSON Converter
Convert CSV spreadsheets to JSON arrays, or JSON arrays of objects back to CSV — instantly in your browser.
JSON ↔ YAML Converter
Convert between JSON and YAML in both directions with line-accurate error messages — ideal for Kubernetes and Docker Compose, entirely in your browser.
JSON Validator
Validate JSON instantly — pinpoints the exact line and column of any error with a plain-English hint. Missing comma, trailing comma, single quotes, unquoted keys. Format and minify too.
Encode / Decode (8)
Base64 Encoder/Decoder
Encode text and images to Base64, or decode Base64 back to text — instantly in your browser.
Image to Base64
Convert images (PNG, JPEG, SVG, GIF, WebP) to Base64 data URIs and back — drag & drop, 100% browser-local, never uploaded.
URL Encoder/Decoder
Percent-encode text and URLs, or decode them back to readable text — instantly in your browser.
JWT Decoder
Decode JSON Web Tokens to inspect their header and payload claims, with readable timestamps — 100% local, in your browser.
Hash Generator
Generate MD5, SHA-1, SHA-256, SHA-384, and SHA-512 hashes in real time — 100% in your browser, nothing sent to a server.
HTML Entity Encoder/Decoder
Encode special characters like < > & into HTML entities, or decode entities back to text — named, decimal, or hex, entirely in your browser.
Binary / Hex Encoder
Convert text to binary, hexadecimal, octal, or ASCII codes — and decode back. Bidirectional, instant, works offline. Free.
Morse Code Translator
Convert text to Morse code and decode Morse back to text. Audio playback at adjustable speed, visual dot-dash display, full reference table.
Converters (9)
Timestamp Converter
Convert Unix timestamps to dates and back, instantly — with live current timestamp and timezone support.
Color Converter
Convert color codes between HEX, RGB, and HSL instantly with a visual color picker — entirely in your browser.
Number Base Converter
Convert numbers between Decimal, Binary, Hexadecimal, and Octal in real time — type in any field, all others update instantly.
Data Size Converter
Convert bytes, KB, MB, GB, TB and PB instantly — type in any field and the rest update live, with decimal (SI, 1000) and binary (IEC, 1024) units side by side.
Temperature Converter
Convert between Celsius, Fahrenheit, Kelvin, and Rankine in real time. Type in any field — all others update instantly. 7 presets, color-coded bar, formula reference.
Roman Numeral Converter
Convert numbers 1–3,999 to Roman numerals or decode Roman numerals back. Step-by-step breakdown, 12 examples (years, Super Bowl, monarchs), symbol chart.
Time Zone Converter
Convert times between any two time zones instantly. World Clock shows live time in 600+ cities. DST-aware, works offline, no signup.
Unit Converter
Convert length, weight, volume, area, and speed between all common units. Inches↔cm, kg↔lbs, miles↔km, gallons↔litres. Click any result to chain conversions.
All Converters
Every unit and data converter in one hub — timestamps, colors, number bases, CSS units, data sizes, temperature, units, Roman numerals and more.
Calculators (11)
Percentage Calculator
Four calculators in one: X% of Y, X is what % of Y, percentage change (increase/decrease), and add/subtract a percentage. Instant results, click to copy.
Age Calculator
Calculate your exact age in years, months, and days. Total days, weeks, hours lived, next birthday countdown, generation label, and zodiac sign.
Finance Calculators
Loan & mortgage payments, tip & bill splitter, and compound interest growth — three financial calculators in one. Instant, free.
Health Calculators
BMI with WHO categories and healthy weight range, plus Calorie/TDEE using the Mifflin-St Jeor equation with macro breakdown. Metric & imperial.
Scientific Calculator
Full scientific calculator with sin, cos, tan, log, ln, √, x², factorial, π, e. DEG/RAD toggle, keyboard input, calculation history. Works offline.
GPA Calculator
Calculate GPA from course grades and credit hours, or find your final grade from weighted components. 4.0 scale, A–F. Add or remove rows. Instant.
Loan & Mortgage Calculator
Calculate monthly loan or mortgage payments, total interest, and a full amortization schedule. Instant and free.
Compound Interest Calculator
See how savings grow with compound interest and monthly contributions. Year-by-year breakdown, any compounding frequency.
Tip Calculator & Bill Splitter
Calculate the tip and split the bill between any number of people. Preset percentages, rounding, per-person totals.
BMI Calculator
Calculate your body mass index with WHO categories and a healthy weight range. Metric and imperial units.
Calorie Calculator (TDEE)
Estimate BMR and daily calorie needs (TDEE) with the Mifflin-St Jeor equation, plus a macro breakdown for your goal.
Design / CSS (9)
CSS Box Shadow Generator
Design layered box-shadow effects with live preview and copy the CSS or Tailwind class — entirely in your browser.
UI Component Library
Browse free, ready-made UI components — buttons, cards, forms, modals, and more — with a live preview and one-click copy of HTML, CSS, and JS.
CSS Gradient Generator
Build linear, radial, and conic CSS gradients with multiple color stops and live preview, then copy the CSS or Tailwind class — entirely in your browser.
CSS Border Radius Generator
Round corners or craft organic blob and fancy shapes with 8-value asymmetric border-radius and live preview, then copy the CSS or Tailwind class — entirely in your browser.
Color Contrast Checker
Check the WCAG contrast ratio between text and background colors with a live preview, and get instant AA/AAA pass/fail for normal and large text — entirely in your browser.
CSS Unit Converter
Convert between px, rem, em, pt, %, vw and vh instantly with a live all-units table. Set your base font size and viewport for accurate results — entirely in your browser.
Color Palette Generator
Generate complementary, analogous, triadic, and tetradic color schemes from any base color, plus a Tailwind-style 50–900 shade scale. Copy HEX, RGB, HSL, and CSS variables — entirely in your browser.
Type Scale Generator
Generate a modular typographic scale from any base size and ratio. Live text preview, rem/px values, copy as CSS custom properties or responsive clamp() output.
Line Height Calculator
Convert CSS line-height between px, unitless, %, and rem. Live text preview, readability rating, WCAG 1.5× recommendation, and 5 presets from Tight to Loose.
Images (12)
QR Code Generator
Create QR codes for URLs, text, Wi-Fi, and email with custom colors and size — download as PNG or SVG, entirely in your browser.
Image Compressor
Compress and resize JPEG, PNG, and WebP images with adjustable quality and max width — batch upload and download, entirely in your browser.
EXIF Data Viewer & Remover
View the camera, settings, and GPS location hidden in your photos, then strip all metadata before sharing — 100% in your browser, never uploaded.
SVG to PNG / JPEG
Convert SVG to high-resolution PNG or JPEG at 1x, 2x, or 4x scale. Paste SVG code or drop a file, choose a transparent or white background — entirely in your browser.
Image Format Converter
Convert images between PNG, JPEG, and WebP — single files or batch — with a quality slider and instant before/after size comparison, entirely in your browser.
Image Cropper & Resizer
Crop, resize, rotate, and flip images with aspect-ratio presets and exact pixel sizing. Drag the crop box, lock a ratio, then export to PNG, JPEG, or WebP — entirely in your browser.
Favicon Generator
Generate a complete favicon set from one image — favicon.ico, 16×16/32×32 PNGs, Apple touch icon, Android Chrome icons, and site.webmanifest. Built entirely in your browser, nothing uploaded.
Image Watermark
Add a text watermark to any image — set font size, color, opacity, and position (9-way grid) or tile it diagonally across the whole image. Export PNG, JPEG, or WebP. Free, no upload.
Image Flip & Rotate
Rotate 90°, 180°, or 270° and flip images horizontally or vertically — apply to many images at once in one batch. Export PNG, JPEG, or WebP. Free, no upload.
Aspect Ratio Calculator
Calculate aspect ratios from dimensions or get pixel sizes from a ratio (16:9, 4:3, 1:1…). Scale proportionally, visual rectangle preview, click to copy.
Image Editor
Multi-layer image editor — add image and text layers, adjust brightness/contrast/saturation per layer, set blend modes and opacity, drag to move and resize. Export PNG/JPEG/WebP.
Image Resizer
Resize images to exact pixel dimensions or a percentage. Lock aspect ratio, batch-resize, convert to JPEG/PNG/WebP. Runs in browser — no upload.
Video (4)
Video Toolkit
Convert to GIF, compress, or trim video clips — all in one browser-based tool. FFmpeg WebAssembly, no upload, 100% private.
Video to GIF Converter
Turn any video clip into an animated GIF. Choose start, duration, FPS and width — runs in your browser, no upload.
Video Compressor
Reduce video file size with adjustable quality and resolution. FFmpeg WebAssembly, 100% in your browser.
Video Trimmer
Cut a video to exact start and end times without re-uploading. Fast, private, browser-based.
Generators (6)
UUID Generator
Generate cryptographically random UUIDs (v4) in bulk, with custom case and hyphen formatting — instantly in your browser.
Password Generator
Generate strong, cryptographically secure passwords with custom length and character sets — entirely in your browser.
Lorem Ipsum Generator
Generate placeholder text by words, sentences, or paragraphs — with HTML paragraph tags or JSON array output, entirely in your browser.
Random Number Generator
Generate cryptographically secure random numbers in any range, produce unique number lists, or pick random items from your own list. Uses crypto.getRandomValues().
Timer & Stopwatch
Online countdown timer with audio alert and stopwatch with lap times. Quick presets for 1–60 min. Works offline, no install required.
Flip a Coin / Dice
Flip a virtual coin with stats, roll any dice (d4–d100, multiple dice), or pick a random winner from a list. Instant, works offline.
Text & Dev Tools (10)
Text Diff Checker
Compare two texts and see every addition and deletion highlighted line by line — instantly in your browser.
Regex Tester
Test and debug regular expressions in real time — matches highlighted instantly, with capture groups and replace mode.
Markdown Preview
Write Markdown and see a live rendered preview instantly — split-pane editor, tables, code blocks, copy HTML.
Word Counter
Count words, characters, sentences, and paragraphs instantly. Includes reading time, speaking time, and social media character limit checks.
Cron Expression Parser
Parse cron expressions into plain English, build schedules visually, and preview the next run times — entirely in your browser.
Text Case Converter
Convert text between camelCase, snake_case, kebab-case, Title Case, and more — one input, all formats at once, entirely in your browser.
Text Sorter & Deduplicator
Sort lines alphabetically, by length, numerically, or shuffle them, and remove duplicate lines — with case-insensitive, trim, and blank-line options, entirely in your browser.
HTTP Status Codes
Every HTTP status code explained — 200 to 511. Search by code or keyword, filter by class (1xx–5xx), expand for details, click to copy. Free, no signup.
MIME Type Lookup
Find the Content-Type for any file extension or look up extensions by MIME type. 65+ types, filter by category, expand for HTTP header example, click to copy.
URL Slug Generator
Convert any title or text to a clean, SEO-friendly URL slug. Hyphen or underscore, stop-word removal, max length, accented character support. Live preview.
100% Free
Every tool on NJHTools is free to use with no hidden limits.
Privacy First
All processing happens in your browser. Your data never touches our servers.
No Account
No sign-up, no email, no account. Just open and use.
Frequently Asked Questions
Are NJHTools free?↓
Yes. All 73 tools on NJHTools are completely free to use, with no paid tier, no trial period and no usage limits.
Do files get uploaded to a server?↓
No. Every tool processes your files and text directly in your browser, so your images, videos, JSON and generated passwords never leave your device. Heavier tools, such as the video tools, download their processing engine to your browser on first use, but your own data is never sent anywhere.
Do I need an account to use NJHTools?↓
No. There is no sign-up, login or email required. Open any tool and start using it immediately.
What tools are available on NJHTools?↓
NJHTools offers 73 free tools in 9 categories: JSON & Data, Encode / Decode, Converters, Calculators, Design / CSS, Images, Video, Generators & Utilities, Text & Dev Tools. Popular tools include the JSON formatter, image compressor, HEIC to JPG converter, video compressor, random number generator, spin the wheel, password generator and QR code generator.