Free Developer & Code Tools & Calculators
Browse 326+ free interactive developer & code calculators, estimators, and utilities. 100% free, private, and runs directly in your browser without signup.
Table Lamp Size Calculator — Bedside, End Table & Desk Lamp Sizing | nrtechstudio.com
What size table lamp for a nightstand? Free bedside, end table, console & desk lamp size calculator with shade proportions and glare check.
TDEE Calculator: 4 Formulas Side-by-Side, Macros & Goal Planner
Free TDEE calculator comparing 4 published formulas (Mifflin-St Jeor, Harris-Benedict, Katch-McArdle, Cunningham) side by side, with BMR, activity levels, cut/bulk goal planner, macro split calculator, worked examples and full methodology. 100% client-side — your data never leaves your browser.
Text to Cron — Convert Plain English to Cron Expressions (Free)
Free text-to-cron converter: type a schedule in plain English and get the cron expression, a plain-English double-check, next 5 runs, and one-click copy. 100% client-side.
Text to CSV Converter
Convert unstructured text, delimited logs, lists, and key-value pairs into formatted CSV files online.
Telegram Link Generator Online
Free Telegram link generator and t.me link maker. Create Telegram
TOML to JSON Converter
Free online TOML to JSON converter — paste TOML or upload a .toml file, get pretty or minified JSON instantly with syntax highlighting, validation, and line-number error messages. 100% client-side.
Torsional Constant Calculator: J for Solid, Hollow and Thin-Walled Sections
Free torsional constant (J) calculator: solid shaft J = pi d^4/32, hollow shaft, thin-walled open and closed sections (Bredt formula), diameter solver
TSConfig Generator
Free online tsconfig.json generator: presets for Node, React, Next.js, libraries and monorepos, visual compilerOptions builder, and tsc-accurate validation.
TSV to CSV Converter - Free Online One-Way Tool
Free TSV to CSV converter: RFC 4180 quoting, delimiter picker, live table preview, file upload, download. One-way tsv to csv only. 100% client-side.
Txt To Html Converter
Txt To Json
ULID Generator — Generate Universally Unique Lexicographically Sortable Identifiers Online Free
Free online ULID generator: create sortable unique IDs in your browser. Bulk generate, decode ULID timestamps, validate format — no signup, client-side.
URL Encoder/Decoder
Free URL encoder and decoder: percent-encode query parameters or full URLs with encodeURIComponent vs encodeURI explained, double-encoding detection, live mode, and a per-character encoding breakdown.
URL Param Decoder (Standalone)
Decode URL query parameters: raw vs decoded table, double-encoding layers, duplicate keys, encoding-type detection, UTM flags. 100% client-side.
URL to MD Link — Free Markdown Link Generator
Free URL to Markdown link generator: wrap any URL in [text](url) syntax with auto-title, Markdown escaping, reference-style and image modes. 100% client-side.
URL Checker & Link Syntax Validator
High-precision online URL checker, link syntax validator, regex URL validation tester, and RFC 3986 URI inspector.
UTF-8 Encoder Online — Text to UTF-8 Bytes
Free UTF-8 encoder online. Convert text to UTF-8 bytes in hex, decimal, or binary with a per-character table of code points and byte sequences. 100% client-side.
UUID Generator — Generate v1, v3, v4, v5, v7 UUIDs Online Free (Bulk + Validator)
Free online UUID generator: create v1, v3, v4, v5 and v7 (RFC 9562) UUIDs in your browser. Bulk generate up to 10,000, validate any UUID, decode v1/v7 timestamps. No signup, 100% client-side.
Java JSON Schema Validator Generator
Interactive Java JSON Schema validator code generator and online schema tester for NetworkNT, Everit, and Jackson.
vCard Parser — Parse vCard to JSON Online
Free online vCard parser: paste vCard text or upload a .vcf file to parse it into structured JSON. vCard 3.0 & 4.0, multi-contact, 100% client-side.
WhatsApp Link Generator Online
Free WhatsApp link generator, WhatsApp link maker, and WhatsApp chat link generator. Create click to chat WhatsApp link (wa.me), link api whatsapp, and QR code.
Wage Garnishment Calculator
Free 2026 wage garnishment calculator: creditor, student loan, child support and IRS levy limits in all 50 states, with federal and state rules.
Watts to VA Converter — Power Factor Lab & UPS Sizer | nrtechstudio
Free watts to VA calculator with power factor lab: convert W↔VA, solve measured PF, draw the power triangle, look up typical device power factors, and size a UPS or generator. 100% client-side — your numbers never leave your browser.
Watts to Watt-Hours Converter + Battery Sizing Lab — nrtechstudio.com
Free watts to watt-hours converter (W ↔ Wh, E = P × t), battery sizing lab with honest DoD + inverter losses, solar panel match, and device runtime table. 100% client-side — your data never leaves the browser.
Web API Security Audit & Header Generator
Interactive web API security audit checklist, security header generator, and API endpoint hardening toolkit.
Web Scraping Tool & Website Data Extractor
Free online web scraping tool and website data extractor. Extract information from website HTML, parse tables, scrape site content, harvest links, extract emails, and generate scraping code.
MAC Address – What Does MAC Address Stand For & OUI Lookup
What does mac address stand for, mac address what is, mac address finder, what does a mac address look like, whats my mac address, mac address vendor, sample of mac address, mac address hardware lookup, define mac address, mac addresses explained, definition mac address, mac address check, mac address full form, decipher mac address, mac address for router, parts of mac address, valid mac address, mac address device identification, decode mac address, how are mac addresses assigned, another name for mac address, mac address lookup tools, mac addresses lookup, mac address acronym, mac address in computer networks, location from mac address, networking mac address, what is mac address in computer, mac address osi, show mac address.
What is Leap Year Definition & Calendar Checker
Interactive leap year tester, historical past leap year dates tracker, and astronomical calendar guide.
Window Blind Size Calculator — Inside & Outside Mount (Free)
Free window blind size calculator: inside-mount deductions, outside-mount overlap, and mount chooser. Exact blind width and height in inches or cm.
Free Online XML Linter — Check XML Style & Formatting Issues
Free online XML linter: catch mismatched tags, duplicate attributes and bad indentation line by line, with one-click auto-fix. 100% private, in-browser.
Standalone - XML Minifier
Minify XML data to reduce file size by removing whitespace.
XML to CSV Converter — Free Online XML to CSV Tool
Convert XML to CSV online free. Flatten nested elements, attributes and namespaces into clean CSV for Excel — 100% in your browser, no upload.
Free Online XML Validator — Check XML, Validate Against XSD DTD
Free online XML validator: check XML well-formedness, validate XML against XSD schema or DTD, and format/beautify XML. Precise line & column errors, hand-rolled XSD 1.0 engine. 100% client-side — private & offline.
YAML Linter & Syntax Checker Online
Free online YAML linter, YAML checker, and YAML syntax validator. Validate YAML online, check YAML indentation, edit and verify YAML files with zero errors.
YAML Minifier — Minify, Beautify & Validate YAML Online
Free online YAML minifier and beautifier. Compress YAML to single-line flow style, pretty-print with custom indent, validate syntax with line/column errors, and measure byte savings. 100% client-side.
YAML to CSV Converter
Free online YAML to CSV converter — flatten nested YAML files into clean CSV spreadsheets with live preview, custom delimiters, and instant download. 100% client-side.
YouTube Embed Code Generator Online
Free YouTube embed code generator. Get YouTube embed code, embed YouTube video HTML, YouTube embed URL, YouTube embed options, YouTube iframe embed generator, create custom YouTube embed code, fast YouTube embed generator.
Barndominium Cost Calculator — Shell vs Turnkey Estimate (2026) | nrtechstudio
Barndominium cost calculator (2026): estimate shell kit vs turnkey cost per sq ft by size, finish & region. Free breakdown, timeline & loan notes.
🔍 No tools matched your search
Try a different keyword like "calculator", "planner", "converter" - or pick a category above.
How to Use the Tools Directory
Every tool is a single interactive page: enter your inputs, get instant results, no account needed. Use the search box (shortcut: press /) to jump straight to a tool, or browse categories when you are exploring. Each card links to the tool's permanent URL, which you can bookmark or share.
Because all computation happens in your browser, the tools are fast, private, and free forever. If a result looks wrong, use the one-click report control on the tool page so it can be fixed.
Tool Categories at a Glance
| Category | What you will find | Example tasks |
|---|---|---|
| Developer | Encoders, formatters, regex, network tools | Format JSON, test regex, subnet a network |
| Finance | Tax, loans, salary, investing | Estimate tax brackets, amortize a loan |
| Home improvement | Estimators, measurements, materials | Size a wire, estimate paint or flooring |
| Health & fitness | Body metrics, nutrition, workouts | Track BMI, plan calories, score fitness tests |
| Math & science | Converters, geometry, statistics | Convert units, solve triangles |
| Text | Counters, sorters, generators | Count words, alphabetize a list |
| Color | Pickers, converters, checkers | Convert HEX to RGB, check contrast |
| Everyday life | Cooking, travel, automotive, pets | Convert recipes, plan fuel costs |
Popular Tasks and Where to Start
| I want to... | Start with | Why |
|---|---|---|
| Convert between number bases | Binary Converter | Step-by-step base conversion with charts |
| Validate and format data | JSON Formatter | Pretty-print and check JSON instantly |
| Count words for an essay | Word Counter | Words, characters, reading time |
| Check password strength | Password Strength Meter | Entropy-based strength scoring |
| Grade text readability | Readability Score | Flesch-Kincaid and grade levels |
| Audit color contrast | Accessibility Checker | WCAG contrast ratios in one click |
Tools Directory FAQ
What is the NRTechStudio tools directory?
It is a free catalog of more than 2,700 interactive web tools: calculators, converters, generators, and checkers for developers, finance, home improvement, health, education, and everyday tasks.
Are all the tools really free?
Yes. Every tool in the directory is free to use with no sign-up, no trial, and no paywall. They run entirely in your browser.
Do I need to create an account?
No. There are no accounts, logins, or subscriptions. Open a tool and use it immediately.
Is my data private when I use these tools?
Yes. The tools are 100% client-side: your inputs are processed by JavaScript in your own browser and never sent to a server.
How do I find the right tool?
Use the search box at the top of the directory (press / to focus it), or browse by category. Every tool card shows a short description of what it computes.
Do the tools work on mobile?
Yes. The directory and the tools use responsive layouts that adapt to phones, tablets, and desktops.
How many tools are there?
The directory holds more than 2,700 tools and grows regularly as new calculators and converters are published.
Can I request a new tool?
Yes. Each tool page has a report/feedback control you can use to request features or new tools; requests help prioritize what gets built next.
Are the tools accurate?
Calculators use published formulas and reference data (tax tables, NEC ampacity, standard conversions). Each tool page documents its method, and issues can be reported in one click for a fix.
Do tools work offline?
Once a tool page has loaded, most tools keep working without a connection because the logic is client-side JavaScript. The directory search needs the page loaded first.
What categories are covered?
Developer utilities, finance and tax, home improvement, health and fitness, math and science, text tools, color tools, networking, education, and everyday life calculators, among others.
Can I bookmark or share a tool?
Yes. Every tool has its own permanent URL under nrtechstudio.com/tools/, which you can bookmark or share directly.
Is there an API for these tools?
The tools are interactive web pages, not API endpoints. The underlying math is plain JavaScript you can inspect in the page source.
Why do some tools show ratings?
Ratings aggregate user feedback to surface the most trusted tools and flag pages that need fixes or better explanations.
How often are new tools added?
New tools are published on a continuous pipeline, prioritized by measured search demand and by user requests from the feedback controls.
Who builds these tools?
NRTechStudio, an independent tools studio focused on free, private, client-side utilities that respect user privacy.