Useful Tools. A Simpler Internet.

🛠 Base64 Decoder Online Free Paste Base64 and read the decoded UTF-8 text instantly — standard or URL-safe, with or without a data: prefix. Free, no sign-up, runs entirely in your browser. EN 🛠 Concrete Mix Calculator Free concrete calculator: turn a slab's length, width and thickness into cubic yards, cubic feet, cubic meters, bags of 60 lb or 80 lb concrete and an estimated cost — instantly, in your browser. EN 🛠 Cursed Font Generator A no-signup, browser-only font mutilator: type a sample, pick a cursed distortion style, drag an intensity slider, watch the specimen rot in real time, and download the result as a real .ttf you can install in any app. EN 🛠 Free Logo Maker Vector Graphics A browser-only logo generator that turns a brand name into a real, downloadable SVG vector lockup (monogram/geometric mark + wordmark), no signup, no watermark. EN 🛠 LLM Token Cost Calculator Paste a prompt (or type a token count) and instantly see estimated input/output tokens plus the per-call cost across GPT, Claude, Gemini, DeepSeek and Llama models, sorted cheapest first. Everything runs in your browser with an editable price table. EN 🛠 AGENTS.md Generator Generate a clean, token-lean AGENTS.md for your repo from three answers: project name, tech stack and rules. Stack-aware command block, deduped rules, copy or download — all in the browser, no signup, no telemetry. EN 🛠 Free Online Lease Agreement Template Fill in a short form and get a complete US residential lease agreement — state disclosure block, rent, deposit, utilities, pets and signature lines — ready to print or save as PDF. No sign-up. EN 🛠 How Do I Create A Free Lease Agreement Free residential lease agreement generator: fill in six short fields and get a complete, printable, ready-to-sign lease with a live paper preview — no sign-up, no watermark, no legal advice. EN 🛠 Fence Post Hole Concrete Calculator Work out how many bags of concrete you need for fence post holes. Enter post count plus hole diameter and depth to get total bags, cubic feet and cubic yards. EN 🛠 Feuille De Calcul Gratuite Free online spreadsheet, no sign-up: type numbers and simple formulas in a browser grid, see totals computed live and download the result as CSV in FR or EN number format. EN 🛠 Exemple De Calcul De Probabilité Calculatrice de probabilité en français : 6 scénarios classiques (événement simple, contraire, réunion, intersection, conditionnelle, au moins un succès) avec la démonstration complète — formule littérale, substitution, calcul, résultat en décimal, pourcentage, fraction simplifiée et cote. EN 🛠 Calcul De La Probabilité A browser-only probability calculator that turns "what are the odds?" into an instant answer — union, intersection, conditional and Bayes probabilities, plus fraction/percentage/odds readouts — for students, analysts and anyone doing quick stats homework or decision math. EN 🛠 Random MAC Generator A no-signup random MAC address generator that emits protocol-valid unicast or multicast addresses — optionally locked to a real vendor OUI — ready to paste into switch ACLs, DHCP reservations, MAC filters and virtual NIC configs. EN 🛠 UUID v7 Generator A no-signup, browser-only bulk UUID v7 (RFC 9562) generator that produces time-ordered, correctly-formatted UUIDs you can copy or download in one click. EN 🛠 AI SEO Title Generator 一个零注册、零等待的中文/英文标题生成器：输入一个主题（可附目标关键词），立刻得到 10 条可直接使用的候选标题。基础标题由浏览器内置的确定性模板引擎在本地瞬间生成，绝不断网失效；在支持 WebGPU 的桌面浏览器上，可一键开启「本地 AI 模式」，用 Transformers.js 从 CDN 加载 Qwen3-0.6B ONNX 模型，在你自己的设备上推理出更自然、更有网感的标题——不上传任何数据、不调用付费接口、不需要 API Key。 EN 🛠 Ebay Seller Fees Calculator Uk A no-nonsense eBay UK seller fee calculator that turns a sale price into real take-home pay in GBP — for UK private and business sellers pricing a listing. Assumes eBay UK's standard final-value-fee model (percentage of item + postage, plus a fixed per-order fee); all rates are editable defaults, not live data from eBay. EN 🛠 LLM Token Counter Paste any prompt or document, pick a model preset and get an instant estimate of the token count and the input cost — free, no sign-up, entirely in your browser. EN 🛠 Markdown to JSON Converter A single-screen converter that turns any Markdown (or GFM) document into a clean, copyable JSON tree — either a generic Markdown AST or Notion-style blocks — so agent workflows, RAG pipelines and CMS importers get structured context in one paste. Runs 100% in the browser: no upload, no account, no rate limit. EN 🛠 Character Counter Online For Twitter A browser-only Twitter/X character counter that shows the real weighted length of a post (URLs = 23, CJK/emoji = 2) and splits long text into numbered threads — for anyone drafting a tweet who needs to know, live, whether it fits. EN 🛠 Ebay Buyer Fee Calculator Live eBay checkout calculator: item price, shipping, quantity, sales tax and handling or import fees in one itemized receipt — see your true out-the-door total. eBay buyers pay no platform fee. EN 🛠 Video Watermark Tool 一个极简的网页工具：上传短视频，输入水印文字，用三个滑杆调好透明度、数量和间距，服务器用 ffmpeg 直接吐出一段带平铺水印的 mp4 下载。不做剪辑、不做账号、不做素材库，只做「加水印」这一件事。 EN 🛠 Video Shot Prompt Board 本地分镜提示词看板：为每个 AI 视频分镜记录 prompt 原文与参考图组，自动存在浏览器里，刷新或重开都不丢，可一键导出整片 Prompt 清单。 EN 🛠 Video First Last Frame Extractor Free in-browser tool that extracts the first and last frame of any video at full resolution and downloads each as a PNG or JPEG. The video never leaves your device. EN 🛠 Free Online Schedule Maker Generator A no-signup weekly schedule maker that turns a list of time blocks into a clean, color-coded timetable you can print or export to a calendar file — for students, shift workers and parents who need a plan in under a minute. EN 🛠 Auto Subtitle Generator Offline Browser-only subtitle timing studio: drop in your video/audio plus the transcript you already have, detect speech locally, and export a perfectly timed .srt or .vtt. Nothing is uploaded, and it does not do speech-to-text. EN 🛠 Font Generator For Discord Servers Turn plain text into 26 fancy Unicode fonts for Discord messages, nicknames and server names, then copy and paste in one tap. EN 🛠 How Can I Create An Invoice Online For Free Free, no-signup invoice maker: fill in a few fields and get a clean, print-ready invoice PDF with correct subtotal, tax and total. Nothing is uploaded. EN 🛠 UTF-8 Encoder Decoder A browser-only UTF-8 encoding, decoding and validation workbench: paste text or hex bytes to convert both ways and get a byte-by-byte report of illegal UTF-8 sequences (orphan continuation bytes, truncated sequences, surrogates, code points beyond U+10FFFF) plus byte / code point / UTF-16 code unit counts. Built for developers and operators debugging mojibake and encoding mismatches. EN 🛠 Live Currency Converter EN 🛠 Add Numbers Online Calculator A no-frills online calculator that adds any list of numbers pasted or typed in one box and shows the live total — for anyone who needs to sum a column of figures without opening a spreadsheet. EN 🛠 Online Calculator Add List Of Numbers Paste-and-sum calculator that turns any messy list of numbers — one per line, comma-separated, space-separated or tab-separated — into a live running total, with a per-line breakdown and rounding controls. EN 🛠 AI Visibility Tracker Free AI visibility checker that generates the exact prompts to test your brand in ChatGPT, Perplexity, Claude, and Gemini. Includes a side-by-side comparison worksheet with Yes/Partial/No toggles and automatic visibility scoring (0-100%) across all 4 AI platforms. Per-model prompt variations to surf 🛠 Date Diff + Age Calculator Free online date calculator with 4 tools in 1: (1) Date difference in years/months/days/hours/minutes/seconds with timezone-aware display; (2) Age calculator with total days/weeks/hours lived + next birthday countdown; (3) Business day counter with custom weekend selection (Mon-Fri default, optional 🛠 Cron Expression Describer + Tester Free online cron tool — paste any cron expression and get a plain-English explanation, field-by-field breakdown of matched values, and the next 10 predicted run times in your chosen timezone. Supports standard 5-field (minute, hour, day-of-month, month, day-of-week) and 6-field (with seconds) cron s 🛠 Hreflang & Canonical Checker Free SEO audit tool to check a page's hreflang tags (validity, duplicates, x-default), canonical link, robots meta, sitemap link, Open Graph and Twitter Card tags, title/meta description lengths, H1 count, and HTML lang attribute. Two input modes: paste HTML source (always works, fully private) or f 🛠 WiFi Signal Strength Checker + Heatmap Free online tool to measure real-world WiFi connection quality in your browser — download speed, upload speed, latency, jitter — and create a manual signal heatmap of your home or office. 100% client-side, no upload. Honest disclosure: browsers cannot read raw RSSI signal strength (security limitati 🛠 PDF Form Filler Free online tool to fill PDF forms directly in your browser. Loads PDF, extracts AcroForm fields, renders the document with click-to-fill overlays, lets you type answers, and saves the completed PDF locally. Supports text fields, checkboxes, radio groups, dropdowns, and option lists. 100% client-sid 🛠 EXIF / Metadata Stripper + Viewer Free online tool to view and strip EXIF metadata from photos. Shows camera, lens, GPS coordinates, settings, and all hidden metadata in your browser. One-click strip removes location, device serial numbers, and edit history. 100% client-side — photos never leave your device. Supports JPEG, PNG, WebP 🛠 Patreon Revenue Calculator Free Patreon earnings calculator — net monthly and annual income after Patreon platform fee (Lite 5% / Pro 8% / Premium 12%), payment processing (2.9% + $0.30), and member churn. Per-tier breakdown with editable tier table (add/remove tiers, set price and members). Includes churn rate, new members p 🛠 YouTube Ad Revenue Estimator Free YouTube ad revenue estimator with country × niche RPM lookup table. Projects monthly and annual earnings from long-form videos, Shorts, Super Chat, channel memberships, Premium revenue, and other sources. 100% client-side, no upload. Includes RPM reference table for 22 niches × 21 countries. Al