Free Online Calculators, Converters & Web Utilities
Zero-friction digital tools for financial planning, file conversions, developer workflows, and daily online productivity - built for maximum speed and data privacy.
Explore Utilities
Showing 18 of 422llms.txt & llms-full.txt Generator for AI Search
Generate standard-compliant /llms.txt and /llms-full.txt files to optimize your website for LLM crawlers, AI search agents, and GEO. 100% browser-based with multi-language and Greek support.
Instagram Unfollowers & Data Export Delta Tracker
Detect who unfollowed you on Instagram using your official data export ZIP. Features snapshot baseline comparison to isolate new unfollows without passwords or external servers.
Lottery Number Picker & Multi-Ball Draw Simulator
Cryptographically secure lottery quick pick generator and multi-ball draw simulator for US Powerball, Mega Millions, EuroMillions, and custom games.
Dog Age to Human Years Biological Converter
Calculate biological canine age into human equivalents using Epigenetic DNA methylation and AVMA breed size metrics.
Spin the Wheel & Choice Picker
Interactive HTML5 wheel spinner for fair random decisions, giveaway drawings, and weighted choices.
Coin Flipper & Probability Simulator
3D interactive coin flipper and high-speed Monte Carlo probability batch simulator backed by Web Crypto API entropy.
Compound Investment & Return Calculator
Calculate long-term compound growth, monthly contributions, and investment returns.
Bernoulli Venturi Tube & Fluid Flow Velocity Solver
Calculate fluid velocity, differential pressure, and volumetric discharge rate through a Venturi tube using Bernoulli's equation, continuity equation, and discharge coefficients.
Internal Rate of Return (IRR) & Multiple on Invested Capital (MOIC) Solver
Calculate Internal Rate of Return (IRR), Multiple on Invested Capital (MOIC), Modified IRR (MIRR), and Net Present Value (NPV) for private equity and venture waterfalls.
Inventory Economic Order Quantity (EOQ) & Holding Cost Calculator
Calculate optimal purchase order lot sizes, balance annual holding vs ordering costs, and set exact reorder points (ROP) with safety stock.
Customer Acquisition Cost (CAC) Payback Period in Months Calculator
Calculate customer acquisition cost payback period in months with gross margin weighting, monthly churn decay, and SaaS unit economic metrics.
Solar SREC & Grid Net Metering Payback Horizon Calculator
Calculate residential and commercial solar PV payback break-even horizons, NEM 1.0 vs NEM 3.0 export credits, SREC market cashflows, and 25-year LCOE returns.
Home Equity Line of Credit (HELOC) Draw & Amortization Calculator
Calculate HELOC interest-only draw payments, repayment phase payment shock, lifetime interest costs, and full amortization schedules.
401(k) Traditional vs Roth Contribution & Tax Bracket Analyzer
Evaluate Traditional vs Roth 401(k) retirement contributions with marginal vs effective tax bracket arbitrage, employer match taxation, and side-car tax savings reinvestment modeling.
Working Capital Ratio & Cash Conversion Cycle (CCC) Calculator
Calculate DIO, DSO, DPO, Cash Conversion Cycle (CCC), Working Capital Ratio, and simulate treasury liquidity release.
Bond Convexity, Modified Duration & Price Volatility Calculator
Calculate Macaulay duration, modified duration, dollar duration (DV01), and analytical bond convexity with second-order Taylor series yield shock projections.
Stock Option Exercise & Alternative Minimum Tax (AMT) Modeler
Model ISO and NSO stock option exercises, calculate phantom AMT tax liability, Form 6251 exemptions, and Form 8801 minimum tax credit carryforwards.
Weighted Average Cost of Capital (WACC) & Hurdle Rate Calculator
Calculate institutional Weighted Average Cost of Capital (WACC), after-tax cost of debt, CAPM cost of equity, and project hurdle rates with sensitivity matrices.
Ultra-Fast Architecture & Modern Web Processing
TwisterTools is built using Next.js 15, TypeScript, and modern browser APIs. Our utilities are engineered for zero-latency user interaction, offering instantaneous execution for financial forecasting, data conversions, document transformations, and developer tools without annoying signup paywalls or intrusive software installations.
Built-In Privacy & Data Security Standards
100% of our utilities execute locally inside your browser memory using WebAssembly and modern browser APIs. Zero files, passwords, or documents are ever uploaded to an external server or database.
Frequently Asked Questions
Is TwisterTools free for personal and commercial use?
Yes. Every tool, generator, converter, and calculator on TwisterTools is completely free to use without subscription fees or registration limits.
How are files and user data handled?
100% of our utilities execute locally inside your browser memory using WebAssembly and modern browser APIs. Zero files, passwords, or documents are ever uploaded to an external server or database.
Can I use TwisterTools utilities offline?
Yes! Once loaded, client-side tools continue to work smoothly even if you disconnect from the internet.