Useful Tools. A Simpler Internet.

🛠 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 🛠 Twitch Bits & Subs to USD Calculator Free Twitch streamer earnings calculator — converts Bits, Tier 1/2/3 subscriptions, Prime subs, ad revenue (RPM × hours × viewers), and external donations into USD. Shows your take-home vs Twitch's platform cut, effective hourly rate, per-sub average, year projection, and revenue source breakdown. 1 🛠 Shopify Profit Calculator Free Shopify profit calculator — net per order after credit card processing, transaction fees, shipping cost, returns allocation, and app subscriptions. Sales tax shown as separate pass-through line (money you collect and remit, not your revenue). 100% client-side, no upload. Includes three tabs: pe 🛠 Amazon FBA Cost Calculator Free Amazon FBA cost calculator — full landed cost per unit including referral fee (by category), FBA fulfillment fee, monthly storage (off-peak and peak blended), long-term storage, returns allocation, inbound placement, and advertising. Three tabs: per-unit profit/margin/ROI breakdown with verdict 🛠 Etsy Fee Calculator Free Etsy fee calculator — instant breakdown of listing, transaction (6.5%), payment processing (3% + $0.25), and offsite ads (15% or 12%) fees. 100% client-side, no upload. Includes a reverse calculator to find the price you need for your target profit margin, plus a scenario comparison (with/witho 🛠 AI Text Humanizer Free online tool that rewrites AI-flavored or formulaic text to sound more natural in your browser. 100% client-side — no upload, no account. Replaces 100+ overused AI words (delve, leverage, robust, comprehensive, moreover, furthermore, etc.), varies sentence rhythm, varies sentence openers, option 🛠 HEIC to JPG Converter Free online tool to convert Apple HEIC / HEIF photos to JPG in your browser. 100% client-side, no upload, no account. Supports batch conversion, JPG quality control, optional resize to 4K/2K/Full HD/HD, and bulk download as a ZIP. Built with heic2any (WebAssembly) for cross-browser HEIC decoding. Pr 🛠 Blog Title Generator Free online tool to brainstorm SEO-friendly blog post titles. Enter a topic and get 12 unique title variants. 146 hand-crafted templates across 8 tones (how-to, listicle, question, comparison, guide, mistakes, trends, opinion). Optional second topic, audience, and constraint fields. Copy individual 🛠 Percent Weight Gain Calculator Turn any two body weights into an accurate percent weight gain or loss figure, plus an optional weekly rate. EN 🛠 Grade Calculator For Teachers Free A free, single-page weighted grade calculator that turns assignment scores into a course percentage and letter grade in seconds — no login, no spreadsheet. EN 🛠 Remove Duplicate Lines Online Paste a list and instantly remove duplicate lines, with optional case-insensitive matching, whitespace trimming, empty-line removal, sorting, duplicate counts, copy and .txt download — all in your browser. EN 🛠 Webpage To Markdown Converter Paste any article or docs URL and get clean, copy-ready GitHub-flavoured Markdown of its text — built for developers, researchers and note-takers who need page content as Markdown for a README, wiki or LLM prompt. Not affiliated with any branded converter; this is a generic HTML→Markdown utility. EN 🛠 Best Online Xml Formatter A fast, private, in-browser XML formatter and validator that beautifies, minifies and error-checks any pasted or dropped XML — no upload, no ads, no account, for developers who just want clean markup in one page. EN 🛠 Xml Sitemap Generator From Url List A no-install browser tool that turns a pasted list of URLs into a valid, downloadable sitemap.xml for SEO submission — serving webmasters, SEO freelancers and developers who already have their URL list and just need the file. Assumes the user supplies URLs (no crawling, no site fetch). EN 🛠 Product Photo Background Remover 纯浏览器内运行的商品图去背景工具：拖入一张商品照片，直接在本地算出软边 alpha 蒙版并导出原分辨率的透明 PNG，图片全程不上传服务器、无登录、无等待排队。 EN 🛠 PDF Accessibility Checker Upload a PDF (≤15 MB) and get a pass/fail verdict plus a fixable issue list for PDF/UA, Section 508 and WCAG 2.1 AA self-checks. EN 🛠 ICS Calendar Generator Type a meeting title, start time and timezone, then download a valid .ics file that imports into Google Calendar, Apple Calendar or Outlook. Runs entirely in your browser — no account, no email, no server round-trip. EN 🛠 Green Screen Remover Remove a green screen in your browser: drop in a chroma key clip or photo, sample the key colour, dial tolerance, and download a transparent PNG or an alpha PNG frame sequence. No upload, no signup, no watermark. EN 🛠 8-Bit SFX Generator Free online 8-bit sound generator and jsfxr-style retro SFX maker: choose a coin, jump, laser, explosion or power-up preset, tweak the waveform and length, preview instantly in the browser and download a real 16-bit 44.1 kHz mono .wav. No sign-up, no plugins, nothing uploaded. EN 🛠 Online Gantt Chart Maker A zero-signup, zero-backend Gantt chart builder: paste your task list and dates, instantly see a clean project timeline, and export it as PNG, CSV or ICS. The free, no-Excel, no-account alternative for simple project timelines. EN