Privacy-First Calculator Suite

The right tool, and the answer.

Precision developer tools, financial math, text utilities, and health calculators. Fast, quiet, and runs entirely in your browser. Ask Echo to translate calculations into insights.

No Data Leaves Your Device

Calculations run completely client-side. No inputs are uploaded, logged, or tracked. It even works offline.

Lightning Fast & Ad-Light

Loads instantly with no cookies, pop-ups, CAPTCHAs, or multi-step funnel walls. Just the tool you need.

Echo Explains Results

Get context on complex numbers. Ask Echo to translate numerical calculations into real-world insights.

Free, No Sign-up Needed

Every single utility is free with no accounts required. Bookmark your favorites and get straight to work.

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Featured Desks

See all 250+ tools
Popular

Financial Desk

Paychecks, loans, tax, and retirement calculators — the money math, worked out in full.

Accurate

Health & Fitness

TDEE, macro calculators, and BMI estimators based on formulas trainers actually use.

Essential

Developer Utilities

Clean, browser-side tools for encoding, decoding, JSON formatting, hashes, and regex.

New

Image Studio

Resize, crop, and convert image formats, or run client-side OCR to extract text from screenshots.

Meet Echo

No more staring at raw numbers.

Echo is the local AI assistant designed to give calculations context. Ask it to translate your mortgage amortizations, nutritional totals, or server latency tests into plain-English advice.

  • Zero-retention chat: Conversations are never stored.
  • Context-aware: Reads calculation outputs instantly.
Echo Preview
You
My loan interest is 7.2%. What is the cost over 15 years?
Echo
At 7.2%, you will pay $63,400 in interest for every $100,000 borrowed. Refinancing or adding $100/mo extra payment reduces the term by 2.4 years.

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Updates & Insights

Product UpdateJuly 5, 2026

Introducing Weather-Responsive Themes

Luminustools now detects local weather patterns to automatically update the palette with solar-themed accents.

PrivacyJune 28, 2026

Why Client-Side Computations Matter

A detailed breakdown of how browser-side JavaScript eliminates the need for server-based processing privacy risks.