TetraKits
TetraKits Blog
In-depth guides for QR codes, PDF workflows, React UI components, and financial planning with free tools you can use immediately.
QR CodesHow to Create a QR Code for WhatsApp (Free Step-by-Step Guide)
Create a free WhatsApp QR code in seconds. Learn wa.me links, print sizes, business card tips, and download a scannable code with TetraKits — no signup required.
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QR CodesHow to Share a Dropbox Video Link with a QR Code (Free Guide)
Share Dropbox video links at events and on print materials using a free QR code. Step-by-step guide for creators, teachers, and marketers — TetraKits QR generator.
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QR CodesQR Code Marketing: 12 Campaign Ideas + Free Tools (2026)
Step-by-step QR code marketing for retail, restaurants, and events. Campaign ideas, design tips that boost scan rates, and a free generator. Read the guide — try the tool free.
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QR CodesBest Free QR Code Generator in 2026 (Compared & Reviewed)
We compared the best free QR code generators for URLs, WiFi, and vCards. See why TetraKits wins on privacy, resolution, formats, and zero signup — full review inside.
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QR CodesHow to Scan a QR Code Online Free (Camera or Image Upload)
Scan QR codes online from your camera or an uploaded image. Free browser-based QR scanner — decode URLs, WiFi, and contacts privately with TetraKits.
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BarcodesProduct Barcode Generator Guide: EAN, UPC & CODE128 (Free)
Create product barcodes for retail and Amazon — EAN-13, UPC-A, CODE128 step-by-step. Free online generator, label tips, and print-ready downloads. Start now.
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CalculatorsCompound Interest Calculator — Growth & Future Value Guide
Calculate compound interest from principal, rate, time, and frequency. See future value and total interest. Free compound interest calculator — no signup.
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CalculatorsLoan Calculator — Monthly Payment & Amortization Guide
Calculate monthly loan payments, total interest, and amortization schedule. Enter principal, rate, and term. Free loan calculator — personal and auto loans.
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CalculatorsPercentage Calculator — Find % Of, Increase & Decrease Guide
Calculate percentages three ways: what is X% of Y, X is what % of Y, and percent increase or decrease. Free online percentage calculator — instant, no signup.
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PDF ToolsMerge PDF Online — Combine PDF Files Free Guide
Combine multiple PDF files into one document in your browser. Drag to reorder and download instantly. Free PDF merger — private, no upload, no signup.
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PDF ToolsSplit PDF Online — Extract Pages Free Guide
Split PDF files by page range or extract every page into separate files. Browser-based with instant download. Free PDF splitter — private, no upload, no signup.
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PDF ToolsCompress PDF Online — Reduce File Size Free Guide
Compress PDF files in your browser with light, balanced, or maximum levels. See size before and after, then download. Free PDF compressor — private, no upload.
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Business ToolsInvoice Generator — Create & Download PDF Invoices Free Guide
Create professional invoices with inline editing, line items, tax, logo upload, and PDF download. Free invoice maker — browser-based, no signup, fully private.
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PDF ToolsPDF Editor Online — Edit Text, Images & Signatures Guide
Edit PDF text, add images and signatures online. Click to change text, place photos, draw signatures, then download. Free PDF editor — private, browser-based.
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CalculatorsScientific Calculator Online — Trig, Log & Exponents Guide
Scientific calculator with trig, logarithms, exponents, roots, and memory. Keyboard support and history. Free browser calculator — no download needed.
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CalculatorsFraction Calculator — Add, Subtract, Multiply & Divide Guide
Add, subtract, multiply, and divide fractions and mixed numbers. Results simplify to lowest terms with decimal form. Free fraction calculator — no signup.
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CalculatorsAverage Calculator — Mean, Median & Mode Online Guide
Calculate mean, median, mode, range, sum, and count from any number list. Paste comma-separated values for instant stats. Free average calculator — no signup.
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CalculatorsGrade Calculator — Weighted Assignment Average Online Guide
Calculate weighted course grade from assignments, scores, and category weights. Track standing by category. Free grade calculator for students — no signup.
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CalculatorsGPA Calculator — Semester & Cumulative GPA Online Guide
Calculate semester GPA from courses, credits, and letter grades. Add or remove classes for weighted average. Free GPA calculator for students — no signup.
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CalculatorsFinal Grade Calculator — What Score Do I Need? Guide
Find the final exam score needed to reach your target course grade. Enter current grade, final weight, and goal. Free final grade calculator — instant results.
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CalculatorsMortgage Calculator — Monthly Payment & Amortization Guide
Calculate monthly mortgage with principal, interest, taxes, insurance, and PMI. See amortization schedule. Free mortgage calculator — home loan estimates.
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CalculatorsBMI Calculator — Body Mass Index with CDC Categories Guide
Calculate BMI with metric or US/UK units, gender, and age. CDC categories, healthy weight range, and chart. Free online BMI calculator — instant, no signup.
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ToolsOnline Notepad — Free Browser Text Editor Guide
Write and save notes with auto-save to local storage. Plain text editor with word count and download. Free online notepad — private, no account, works offline.
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ToolsRGB Color Codes — Named Colors & HEX Reference Guide
Browse 140+ named CSS colors with HEX, RGB, and HSL values. Search by name and copy any format. Free RGB color reference for designers — instant copy.
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ToolsASCII Table — Decimal, Hex, Binary & HTML Codes Guide
Interactive ASCII table with expand grid and detail view. Decimal, hex, binary, HTML entities for codes 0–127 and extended 128–255. Free online reference.
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ToolsHTML Editor — Live Preview Side by Side Online Guide
Write HTML with instant live preview, sample templates, and download. Split-pane editor for learning and prototyping. Free browser HTML editor — no signup.
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ToolsHTML Viewer — Preview & Render HTML Online Guide
Paste HTML and see rendered output instantly. Preview pages, snippets, and email templates in a sandboxed iframe. Free HTML viewer — private, no server upload.
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ToolsPassword Generator — Strong Random Passwords Online Guide
Generate strong random passwords with custom length and character sets. Strength meter with copy. Free password generator — private, runs in your browser.
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ToolsRandom Number Generator — Pick Random Integers Online Guide
Generate random integers in any range with exclusions and unique picks. Copy results instantly. Free random number generator — crypto-fair, browser-based.
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ToolsWord Counter — Count Words, Characters & Reading Time Guide
Count words, characters, sentences, paragraphs, and reading time. Live stats as you type for essays and blogs. Free word counter — private, no signup.
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ToolsCharacter Counter — Count Chars, Words & Lines Online Guide
Count characters with and without spaces, words, sentences, paragraphs, and lines. Live stats as you type. Free character counter for SEO and social — private.
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ToolsBase64 Encoder & Decoder — Encode Text Online Guide
Encode or decode Base64 text instantly. Switch modes with live output and one-click copy. Free Base64 encoder — private, browser-based, no signup required.
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ToolsColor Picker — HEX, RGB & HSL Values Online Guide
Pick any color and copy HEX, RGB, and HSL values instantly. Visual swatch with sliders for web design. Free online color picker — browser-based, no signup.
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PDF ToolsImage to PDF Converter — JPG PNG to PDF Online Guide
Convert JPG, PNG, and other images to PDF in your browser. Arrange images, set page size, and download. Free image to PDF converter — private, no upload.
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CalculatorsSimple Interest Calculator — I = PRT Formula Online Guide
Calculate simple interest with principal, rate, and time. See interest earned and total amount using I = P×R×T. Free simple interest calculator — no signup.
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ToolsUnit Converter — Length, Weight, Temperature & More Guide
Convert length, weight, temperature, volume, area, speed, time, and storage. Live results with formula display. Free unit converter — metric and imperial.
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CalculatorsDiscount Calculator — Sale Price & Percent Off Online Guide
Calculate discount amount and final sale price from original price and percent off. See savings instantly. Free discount calculator for shopping — no signup.
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CalculatorsStandard Deviation Calculator — Sample & Population σ Guide
Calculate standard deviation, variance, mean, and count from any list. Population and sample modes. Free standard deviation calculator — instant stats.
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CalculatorsAge Calculator — Exact Years, Months & Days Online Guide
Calculate exact age in years, months, days, and total days from birth date. Optional as-of date for historical checks. Free online age calculator — no signup.
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ToolsDate Calculator — Add, Subtract & Days Between Dates Guide
Add or subtract days, weeks, months, and years from any date. Find days between two dates with weekday names. Free online date calculator — instant, no signup.
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ToolsHTML Entity Codes — Named & Numeric Character Reference Guide
Browse HTML entity codes for symbols, arrows, currency, math, and special characters. Copy named or numeric codes. Free HTML entity reference — one-click copy.
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ToolsMath Symbols Reference — Copy Greek & Operators Online Guide
Browse and copy math symbols, Greek letters, operators, and notation for equations. Search by name or symbol. Free math symbols reference — one-click copy.
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ToolsTime Calculator Guide: Add, Subtract & Duration Online
Add or subtract hours and minutes from a time, or find duration between two times. Free browser time calculator — TetraKits.
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CalculatorsVAT Calculator Guide: Add & Remove Value Added Tax
Calculate VAT amount, net, and gross prices with any rate. Add or remove VAT for invoices — TetraKits.
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CalculatorsGST Calculator Guide: Add & Remove Goods and Services Tax
Calculate GST on net or gross prices with AU, NZ, IN, and SG presets. Free online GST calculator — TetraKits.
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ToolsAlt Codes Guide: Windows Keyboard Character Shortcuts
Search Alt codes for currency, math, Greek, and accent characters on Windows. Click to copy — TetraKits.
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ToolsWorld Clock Guide: Live Time Across Time Zones
See live time in cities worldwide. Add timezones and plan meetings across zones — TetraKits.
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ToolsURL Encoder Guide: Percent-Encoding Query Strings & Decode
Encode and decode URLs with component (encodeURIComponent) or URI mode. Examples, mode comparison, and free percent-encoding tool — TetraKits.
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CalculatorsTip Calculator Guide: Split Bills & Restaurant Gratuity
Calculate tip amount, total with gratuity, and per-person share. US tip rates, splitting guide, and free restaurant tip calculator — TetraKits.
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CalculatorsSales Tax Calculator Guide: Add & Remove US Sales Tax
Add or remove US sales tax with CA, NY, TX, FL, and WA presets. Formulas, examples, and free sales tax calculator — TetraKits.
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ToolsOnline Timer Guide: Free Countdown with Pause & Reset
Set a countdown timer in hours, minutes, and seconds. Cooking, workouts, Pomodoro — free browser timer guide — TetraKits.
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ToolsOnline Stopwatch Guide: Lap Times & Split Intervals
Start, lap, and reset an online stopwatch with centisecond splits. Workout and experiment timing guide — TetraKits.
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CalculatorsQuadratic Equation Guide: Formula, Discriminant & Roots
Solve ax² + bx + c = 0 with the quadratic formula. Discriminant explained, examples, and free quadratic calculator — TetraKits.
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CalculatorsGCF and LCM Calculator Guide: Greatest Common Factor
Find GCF (GCD) and LCM of two or more integers. Fraction simplification and common denominator guide — TetraKits.
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CalculatorsRatio Calculator Guide: Simplify Ratios to Lowest Terms
Reduce ratios to simplest form and convert to decimal. Examples and free ratio simplifier — TetraKits.
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CalculatorsLetter Grade to GPA Converter Guide — 4.0 Scale
Convert letter grades to GPA and GPA to letter grades. Full A+ through F reference table — TetraKits.
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ToolsCase Converter Guide: camelCase, snake_case & Title Case
Convert text to UPPERCASE, lowercase, Title Case, Sentence case, camelCase, or snake_case. Developer and writer guide — TetraKits.
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ToolsHTML Table Generator Guide: Build Tables with Preview
Generate HTML table code with rows, columns, header row, and borders. Live preview and copy-ready markup — TetraKits.
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ToolsHash Generator Guide: SHA-256 & SHA-512 Online
Generate SHA-256, SHA-512, and other hash digests from text. Free browser hash generator — TetraKits.
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ToolsJSON Formatter Guide: Pretty Print & Validate Online
Format, minify, and validate JSON in your browser. Free JSON pretty printer — TetraKits.
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ToolsJWT Decoder Guide: Read Token Header & Payload
Decode JWT tokens to inspect header and payload claims. Free browser JWT decoder — TetraKits.
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ToolsUUID Generator Guide: Create v4 Random UUIDs Online
Generate single or bulk UUID v4 identifiers. Free random UUID generator — TetraKits.
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ToolsText Diff Guide: Compare Two Texts Online
Compare two text blocks and highlight line differences. Free online text diff — TetraKits.
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ToolsDuplicate Line Remover Guide: Deduplicate Text Online
Remove duplicate lines from text lists instantly. Free deduplication tool — TetraKits.
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ToolsLine Sorter Guide: Sort Lines & Reverse Text
Sort lines alphabetically or by length and reverse text strings. Free line sorter — TetraKits.
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ToolsLorem Ipsum Generator Guide: Placeholder Text for Design
Generate lorem ipsum paragraphs for mockups and wireframes. Free placeholder text generator — TetraKits.
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ToolsWords to Time Calculator Guide: Convert Word Count to Minutes
Convert words to time for speeches, scripts, and blog posts. See the 238 WPM formula, examples, and a free word-to-time calculator. Try it instantly — no signup.
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PDF ToolsPDF to Image Guide: Convert PDF Pages to PNG & JPEG
Convert PDF pages to PNG, JPEG, or WebP images in your browser. Free PDF to image converter — TetraKits.
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PDF ToolsRotate PDF Guide: Fix Page Orientation Online
Rotate PDF pages 90°, 180°, or 270° in your browser. Free PDF rotator — TetraKits.
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PDF ToolsPDF Page Reorder Guide: Rearrange Pages Online
Drag and drop to reorder PDF pages in your browser. Free PDF page rearranger — TetraKits.
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PDF ToolsPDF Watermark Guide: Add Text Watermark Online
Add custom text watermarks to PDF pages in your browser. Free PDF watermark tool — TetraKits.
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CalculatorsBinary Converter Guide: Decimal, Hex & Octal Online
Convert between binary, decimal, hexadecimal, and octal. Free number base converter — TetraKits.
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CalculatorsRoman Numeral Converter Guide: Number ↔ Roman Online
Convert numbers to Roman numerals and decode Roman strings. Free Roman numeral converter — TetraKits.
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CalculatorsPercentage Change Calculator Guide: Increase & Decrease
Calculate percent change between two values. Free percentage increase and decrease calculator — TetraKits.
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CalculatorsPaycheck Calculator Guide: Estimate Net Pay After Tax
Estimate net take-home pay after federal tax, state tax, and deductions. Free paycheck calculator — TetraKits.
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Business ToolsDraw Signature Online Guide: Transparent & White PNG
Draw your signature in the browser and download as PNG with transparent or white background. Free online signature pad — TetraKits.
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UI LibraryTetraKits UI Library Guide: 68+ Free React Components (2026)
Browse TetraKits UI: 68+ free React and Tailwind components with live previews, copy-ready TSX, npm install notes, and AI prompts. Heroes, GSAP footers, bento grids, and buttons.
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UI LibraryFree React UI Library: Copy Paste Components for Next.js and Vite
Free React UI library with 68+ Tailwind components. Copy TSX for heroes, footers, bento grids, and buttons. Live previews, npm install notes, and AI prompts on TetraKits UI.
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