Free Simulators

Calculator Box is a leading free online calculator hub, offering 3,286 formula-based calculators across 18 fields including math, finance, health, physics, statistics, and chemistry. All tools require no sign-up, no ads, and no tracking, with calculations running locally in your browser to ensure privacy and security. Each calculator not only delivers results but also shows the underlying formula, worked examples, and related tools, helping users truly understand the calculation logic. It's a one-stop online calculator reference library for everyday problem-solving and professional computation.

IGX.gg is an online marketplace dedicated to in-game asset trading, providing players with secure services for buying and selling game currency, items, and accounts. The platform covers popular games such as Diablo IV, Old School RuneScape, Path of Exile 2, College Football 27, and World of Warcraft. IGX ensures transaction security through three core mechanisms: seller verification, transparent pricing, and delivery tracking. IGX offers an AI-powered intelligent search assistant; users can simply describe their needs (e.g., "500 Chaos Orbs" or "budget build") and the AI will automatically compare prices, match the best deals, and recommend optimal transactions. The platform also provides free tools like a POE2 Build Planner, along with exclusive coupons for new users (50% off the first order + 30% off the second). All transactions are protected by IGX Buyer Protection, support multiple payment methods, and include complete order tracking with delivery evidence records.

SealDigital is an AI-driven online seal design platform offering professional-grade seal generation at the industry's lowest price of $2.4. Users can complete the entire process from template selection to export in just 5 seconds via a browser, with no design experience required. The platform supports synchronous export in 4 formats (PNG, SVG, PDF, DOCX), featuring built-in AI smart layout recommendations, automatic text typesetting, real-time contrast checks, aging effects, and anti-counterfeit serrated edges as advanced security functions. It covers 6 major industry scenarios: corporate seals, legal notarization, wedding events, educational institutions, healthcare, and more. All exported files are watermark-free and come with permanent commercial usage rights. Already serving 50,000+ seal creations, it has been recommended by Product Hunt, Wired Business, Twelve Tools, and other platforms.

StampDy is a free online stamp design tool that allows you to create professional-grade stamps quickly in your browser without registration. It supports various shapes including circular, rectangular, oval, triangular, and square. You can add custom text (including circular text), upload logos/icons, adjust font styles/size/spacing/rotation/alignment, and apply aging effects to simulate real rubber stamp textures. Export formats include PNG, SVG, EPS, PDF, and DOCX, with support for 1x/3x/10x multi-resolution exports and transparent backgrounds. The platform also offers an AI stamp generator, a PDF editor (supporting stamp insertion and e-signatures), and e-signature request features (featuring SHA-256 hashing, audit trails, and completion certificates). Flexible pricing plans include $2.4 per single use, $15.9/month unlimited, $119/year, and $299 lifetime access, catering to all scenarios from occasional personal use to high-frequency enterprise needs.

Tai Chi Walking Guide is a free Tai Chi walking guide website for adults aged 45 and over, seniors, beginners, and caregivers. No login or payment required; all content is accessible directly in your browser with progress saved locally on your device. The site offers an interactive voice coach (including metronome, senior slow mode, and chair-assist prompts), a 7-day free progressive course (from standing weight transfer to continuous slow walking), printable practice cards, instructional videos, and detailed safety guidelines. Content is evidence-based, citing authoritative sources like NIH NCCIH and Harvard Health, emphasizing safety first, with all health claims accompanied by cautious language and never overstating benefits.

HumanDesignChart.org is a free online Human Design calculation tool that combines the I Ching, astrology, Kabbalah Tree of Life, chakra systems, and quantum physics to provide precise ephemeris-level birth chart analysis. Simply enter your date of birth, time, and location to instantly generate an interactive SVG bodygraph in your browser containing energy types (Generator/Projector/Manifestor/Manifesting Generator/Reflector), decision strategies and inner authority, life profile (Profile), all nine energy centers, 64 gates, 36 channels, and variables (Variables). All calculations are performed locally in the browser: 100% free, no registration required, no personal data stored. Supports dual-person relationship chart comparison, serving 10,000+ users with precision up to 1-second ephemeris data.

Loop Engineering is an intelligent operations system designed for AI SaaS teams, transforming product feedback into an auditable and verifiable continuous improvement loop. Unlike single-prompt tools, Loop Engineering builds a complete Agent engineering control framework: it automatically discovers and categorizes issues through signal inputs (supporting 6 major sources such as tickets, CLI feedback, error logs, user research, search queries, etc.), executes code changes in isolated workspaces (Worktrees), and subjects them to independent verification via a Verifier for build validation, type checking, visual QA, security scanning, SEO auditing, and smoke testing. Finally, decisions, blockers, and evidence are written to the memory system for reuse in subsequent runs. It supports multi-Agent coordination across Claude Code, Codex, Cursor, Windsurf, Gemini CLI, and more, covering the full spectrum from second-level coding loops to hour-level development feedback and week-level external feedback. This empowers product managers, growth teams, support teams, and engineering leads to make decisions based on evidence rather than guesswork.

AI Toolbox is a browser-based, free online video splitting tool that supports mainstream formats including MP4, WebM, MOV, MKV, and AVI. It requires no file uploads, no registration, and adds no watermarks. All processing is performed locally using FFmpeg compiled via WebAssembly, ensuring 100% privacy and security. It offers four splitting methods: manual precise splitting with timeline preview, equal portion splitting, duration-based splitting, and file size-based splitting. It also supports Fast Mode for stream copying (ultra-fast splitting) and advanced re-encoding mode, meeting diverse editing needs from social media shorts to 4K high-definition footage.