# Free Tool Arena

> Free Tool Arena is a free, browser-based catalog of 785+ tools and 585+ guides across 21 categories. Money tools include mortgage, loan, compound-interest, tip, and tax calculators. Productivity has Pomodoro timers, world clocks, scratchpads, and habit trackers. Health covers BMI, calorie, macro, sleep, and pregnancy calculators. Developer tools include JSON formatter, regex tester, JWT decoder, subnet calculator, IPv6 expander, chmod calculator, htpasswd generator, and Excel formula explainer. AI tools cover prompt builders, token counters, and AI cost estimators. Design tools include CSS gradient/grid/loader generators, color palette extractors, and font pair pickers. Plus 20 browser games, 102 glossary terms, 98 head-to-head comparisons, and 17 curated lists. Every tool runs entirely in the browser — nothing you type or upload leaves your device.

Each tool is one focused job; each guide is one short answer to one specific question. 790 tools and 590 guides total.

This file is a curated index for LLMs and AI agents per llmstxt.org. For the full machine-readable list of every URL on the site, see [sitemap.xml](https://freetoolarena.com/sitemap.xml).

## Curated lists (best entry points)

- [Best Free Tools for Freelancers](https://freetoolarena.com/best/free-tools-for-freelancers): Free tools for freelancers: invoice generator, freelance rate calculator, tax estimator, cash-flow tracker, and more. No signup, browser-based, works offline.
- [Best Free Tools for Students](https://freetoolarena.com/best/free-tools-for-students): Free tools for students: Pomodoro timer, word counter, GPA calculator, weekly planner, readability checker, and more. No account, no ads, just the tools.
- [Best Free Developer Tools](https://freetoolarena.com/best/free-dev-tools): Free developer tools: JSON formatter, regex tester, JWT decoder, hash generator, UUID generator, cron builder, and more. No signup, all in-browser.
- [Best Free SEO Tools](https://freetoolarena.com/best/free-seo-tools): Free SEO tools: SERP snippet preview, schema markup generator, FAQ schema, meta tag generator, headline analyzer, keyword density checker, and more.
- [Best Free Finance Calculators](https://freetoolarena.com/best/free-finance-calculators): Free finance calculators: mortgage, loan, compound interest, budget, tax, 401(k), Roth IRA, retirement, debt payoff. No signup, in-browser, mobile-friendly.
- [All 17 curated lists](https://freetoolarena.com/best): every "best free tools for X" list

## Popular tools

- [Loan Calculator](https://freetoolarena.com/tools/loan-calculator): Work out monthly payments and total interest on any loan. Enter amount, rate, and term — get a clear breakdown in seconds.
- [Mortgage Calculator](https://freetoolarena.com/tools/mortgage-calculator): Estimate your monthly mortgage payment, total interest, and payoff schedule. Free, fast, and mobile-friendly.
- [Compound Interest Calculator](https://freetoolarena.com/tools/compound-interest-calculator): See how much your money grows with compound interest. Add starting balance, monthly contributions, and watch the curve.
- [Calculator](https://freetoolarena.com/tools/calculator): Free 4-function calculator with full keyboard support. Add, subtract, multiply, divide. No ads in the way, runs offline.
- [Scientific Calculator](https://freetoolarena.com/tools/scientific-calculator): Expression-based scientific calculator with trig, log, sqrt, exp, pi, e. DEG/RAD toggle. History. Free, no eval.
- [JSON Formatter](https://freetoolarena.com/tools/json-formatter): Paste JSON to format, validate, and minify. Clear error messages with line numbers. Free and runs in your browser.
- [Regex Tester](https://freetoolarena.com/tools/regex-tester): Test regular expressions against sample text with live match highlighting. Supports common flags and groups.
- [Password Generator](https://freetoolarena.com/tools/password-generator): Generate strong random passwords. Choose length, symbols, numbers, and avoid lookalikes. Runs locally.
- [QR Code Generator](https://freetoolarena.com/tools/qr-code-generator): Generate QR codes for URLs, text, wifi, or email. Customize size and error level. Download PNG or SVG — free and offline.
- [Subnet / CIDR Calculator](https://freetoolarena.com/tools/subnet-calculator): Calculate IPv4 subnets from CIDR or dotted mask: network, broadcast, host range, usable hosts, wildcard, binary. Free, browser-only.
- [All 790 tools](https://freetoolarena.com/tools): full catalog

## Tool categories

- [Money & Finance (107 tools)](https://freetoolarena.com/tools/category/money): Budget, loan, interest, and paycheck math — in seconds.
- [Productivity (34 tools)](https://freetoolarena.com/tools/category/productivity): Timers, planners, and routines for focused work.
- [Health & Fitness (43 tools)](https://freetoolarena.com/tools/category/health): Quick calculators and plain-English habit guides.
- [Text & Writing Utilities (58 tools)](https://freetoolarena.com/tools/category/text): Count, format, clean, and convert text in a tab.
- [Developer Utilities (124 tools)](https://freetoolarena.com/tools/category/dev): Formatters, generators, and regex tools for daily dev work.
- [Unit Converters (17 tools)](https://freetoolarena.com/tools/category/units): Length, speed, temperature, and more — no ads, no math.
- [Random & Fun (15 tools)](https://freetoolarena.com/tools/category/random): Coin flips, dice, and decision makers when you just need an answer.
- [Writing & Content (27 tools)](https://freetoolarena.com/tools/category/writing): Write better, start a blog, grow an audience online.
- [Career & Growth (58 tools)](https://freetoolarena.com/tools/category/career): Interviews, résumés, promotions, and smart career moves.
- [Home & Life (58 tools)](https://freetoolarena.com/tools/category/home): A calmer, cleaner, better-run home life — one habit at a time.
- [Relationships & Social (2 tools)](https://freetoolarena.com/tools/category/social): Friendships, hard conversations, and social skills that travel.
- [File & Format Converters (79 tools)](https://freetoolarena.com/tools/category/converters): PDFs, images, data formats — converted in your browser, offline-safe.
- [Audio, Video & Voice (19 tools)](https://freetoolarena.com/tools/category/media): Record, trim, convert, and transcribe audio + video — all in your browser.
- [AI & Prompt Tools (53 tools)](https://freetoolarena.com/tools/category/ai): Prompt builders, token counters, and prompt libraries for ChatGPT, Claude, Gemini, and image models.
- [Gaming (23 tools)](https://freetoolarena.com/tools/category/gaming): Sensitivity converters, DPS calculators, bracket generators, and the math for Minecraft, D&D, and MTG.
- [Games (20 tools)](https://freetoolarena.com/tools/category/games): Quick browser games for breaks — snake, 2048, tic-tac-toe, memory, hangman, word puzzles.
- [Automotive (16 tools)](https://freetoolarena.com/tools/category/automotive): Car loans, fuel economy, depreciation, insurance, tires, and the full cost of owning a vehicle.
- [Cooking & Food (13 tools)](https://freetoolarena.com/tools/category/cooking): Recipe scaling, baking conversions, coffee ratios, food storage times — the kitchen math that doesn't change.
- [Parenting & Baby (13 tools)](https://freetoolarena.com/tools/category/parenting): Pregnancy, baby feeding, sleep schedules, growth percentiles, and the daily calculators parents actually need.
- [Pets (11 tools)](https://freetoolarena.com/tools/category/pets): Dog and cat age conversions, food amounts, vaccine timing, travel and boarding costs — practical pet math.

## Guide categories

- [AI & LLMs guides (108)](https://freetoolarena.com/guides/category/ai): Practical, plain-English guides for ChatGPT, Claude, Gemini, and image models — prompt patterns, token limits, cost math, and agent setup.
- [How-To & Life guides (234)](https://freetoolarena.com/guides/category/how-to): Short, specific how-tos for everyday life: habits, health, home, money, relationships, and the small skills that compound.
- [Using Our Tools guides (63)](https://freetoolarena.com/guides/category/tools): Walk-throughs for the calculators, converters, and utilities on this site — when to use which, with examples and common mistakes.
- [Money & Business guides (91)](https://freetoolarena.com/guides/category/business): Budgets, debt, salary, freelancing, and building a side income — the money math that actually changes your month.
- [Developers & Technical guides (57)](https://freetoolarena.com/guides/category/technical): Coding, developer workflow, and engineering how-tos — clean code, shipping faster, and breaking into the industry.
- [Productivity & Focus guides (21)](https://freetoolarena.com/guides/category/productivity): Time management, deep work, task systems, and the habits that let you finish real work — not performatively look busy.
- [Design & Media guides (16)](https://freetoolarena.com/guides/category/design-media): Images, video, color, typography, and the everyday creative workflow — compress without losing quality, crop without guessing.
- [All 590 guides](https://freetoolarena.com/guides): full guide library

## Comparisons (99)

Head-to-head comparisons of tools, services, and decisions, with opinionated verdicts.

- [All comparisons](https://freetoolarena.com/compare)
- [15-year vs 30-year mortgage](https://freetoolarena.com/compare/15-year-vs-30-year-mortgage): 15-year vs 30-year mortgage compared: monthly payment, total interest, flexibility, and who each term is actually best for. Use our free calculator to run the numbers on your own loan.
- [Roth IRA vs Traditional IRA](https://freetoolarena.com/compare/roth-ira-vs-traditional-ira): Roth IRA vs Traditional IRA: how each is taxed, who each is for, and which gives you more retirement spending power. Free compound interest calculator included.
- [401(k) vs Roth IRA](https://freetoolarena.com/compare/401k-vs-roth-ira): 401(k) vs Roth IRA head-to-head: employer match, contribution limits, tax treatment, and the exact order to fund them. Free projection tools included.
- [Debt avalanche vs snowball](https://freetoolarena.com/compare/avalanche-vs-snowball-debt-payoff): Debt avalanche vs snowball method: which pays off credit cards faster, and which one most people actually stick with. Run your real balances in our free calculator.
- [FHA vs conventional loan](https://freetoolarena.com/compare/fha-vs-conventional-loan): FHA vs conventional mortgage: down payment, credit score, PMI rules, and total cost. Use our free FHA and mortgage calculators to model your own numbers.
- [SVG vs PNG](https://freetoolarena.com/compare/svg-vs-png): SVG vs PNG compared: quality, file size, scaling, browser support, and when to use each. Includes a free SVG-to-PNG converter for when you need both.
- [JPG vs PNG](https://freetoolarena.com/compare/jpg-vs-png): JPG vs PNG compared: compression, quality, transparency, and the right format for photos, screenshots, and logos. Free converters included.
- [JSON vs YAML](https://freetoolarena.com/compare/json-vs-yaml): JSON vs YAML head-to-head: readability, comments, whitespace rules, parser ecosystem, and when to use each. Free JSON formatter and YAML formatter included.
- [Pomodoro vs Flowtime](https://freetoolarena.com/compare/pomodoro-vs-flowtime): Pomodoro vs Flowtime method: fixed timer boxes vs flexible flow tracking, and which one actually gets more deep work done. Free browser-based Pomodoro timer included.
- [Base64 vs Hex encoding](https://freetoolarena.com/compare/base64-vs-hex-encoding): Base64 vs Hex encoding compared: size overhead, readability, URL safety, and typical use cases. Free Base64 encoder/decoder included.

## Glossary (138)

Plain-English definitions with cross-links to relevant tools.

- [All glossary terms](https://freetoolarena.com/learn)
- [APR](https://freetoolarena.com/learn/apr): APR (Annual Percentage Rate) is the total yearly cost of borrowing money, expressed as a percentage — including the interest rate plus most fees. It's the number you should compare between loans, not the 'interest rate'.
- [APY](https://freetoolarena.com/learn/apy): APY (Annual Percentage Yield) is the total yearly return on a savings account, CD, or investment — expressed as a percentage and including the effect of compounding. When comparing savings products, APY is the fair number.
- [Compound interest](https://freetoolarena.com/learn/compound-interest): Compound interest is interest earned on both your original money AND the interest it's already earned. Over long periods, this 'interest on interest' effect is what turns modest monthly contributions into retirement-level balances.
- [Amortization](https://freetoolarena.com/learn/amortization): Amortization is the process of paying off a loan with equal periodic payments that are split between interest and principal. In the early months, most of your payment goes to interest; as the balance shrinks, more goes to principal.
- [ROI](https://freetoolarena.com/learn/roi): ROI (Return on Investment) is a percentage that measures profit relative to the cost of an investment. It answers 'how much did I make for every dollar I put in?'
- [Canonical URL](https://freetoolarena.com/learn/canonical-url): A canonical URL is the one 'official' URL for a piece of content, declared to search engines via a <link rel="canonical"> tag. It tells Google 'if you find this page at multiple URLs, treat this one as the main version.'
- [Meta description](https://freetoolarena.com/learn/meta-description): A meta description is a 150-160 character HTML tag that summarizes a web page. Google often uses it as the search-result snippet beneath the blue title — which directly affects click-through rate.
- [JSON-LD](https://freetoolarena.com/learn/json-ld): JSON-LD (JSON for Linked Data) is the format Google prefers for structured data on web pages. It embeds Schema.org markup as a <script type="application/ld+json"> block, telling search engines exactly what kind of content a page contains.
- [Schema (Schema.org)](https://freetoolarena.com/learn/schema): Schema.org is a shared vocabulary of types (Article, Product, Event, FAQPage, etc.) that websites use to describe their content in a machine-readable way. Google and Bing use Schema.org to generate rich results.
- [robots.txt](https://freetoolarena.com/learn/robots-txt): robots.txt is a small text file served at /robots.txt that instructs search-engine crawlers which parts of a site they can and can't crawl. It's a suggestion, not a lock — well-behaved bots honor it.

## Programmatic surfaces

- [/sitemap.xml](https://freetoolarena.com/sitemap.xml): full machine-readable URL index
- [/sitemap.html](https://freetoolarena.com/sitemap): human-friendly browseable sitemap
- [/feed.xml](https://freetoolarena.com/feed.xml): RSS feed of recent guides
- [/opensearch.xml](https://freetoolarena.com/opensearch.xml): OpenSearch description for "add as search engine"
- [/og](https://freetoolarena.com/og): dynamic OG image generator (params: slug, title, eyebrow, lang)
- [/api](https://freetoolarena.com/api): public JSON endpoints for select tools (mortgage, loan, compound interest, BMI, tip)

## About

- [About Free Tool Arena](https://freetoolarena.com/about)
- [How our tools work](https://freetoolarena.com/how-it-works)
- [Editorial policy](https://freetoolarena.com/editorial)
- [What's new](https://freetoolarena.com/whats-new): release log
- [Suggest a tool](https://freetoolarena.com/suggest)

## License

Tool implementations are MIT-licensed where source is available. Editorial content (guides, comparisons, glossary) is © Free Tool Arena, and may be cited with attribution but not republished verbatim. The site explicitly welcomes LLM-driven discovery and citation — link back when summarizing.