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Hundreds of free, expertly built calculators and online tools for finance, health, math, everyday life, Christmas, Islamic, Hindu, text, images, PDFs, developers and more — all running in your browser with no tracking.
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Calculators on the left for every life decision; on the right, online tools for text, images, PDFs, developers and design.
Featured calculators
The most-used calculators on CalcaTools — useful, fast, and accurate.
Mortgage Calculator | Estimate Monthly Home Loan Payments
Estimate monthly mortgage payments with taxes and insurance.
BMI Calculator | Measure BMI and See Weight Category
Check your Body Mass Index and healthy weight range.
Loan Calculator | Estimate Monthly Payment and Total Interest
Calculate loan payments, interest and full amortization.
Percentage Calculator | Solve X% Of Y And Percent Change
Calculate percentages, increases, decreases and ratios.
Compound Interest Calculator | Project Savings Growth Over Time
See how your investments grow with compound interest.
Age Calculator | Get Exact Age Between Two Dates
Calculate exact age in years, months, days and seconds.
Zakat Calculator | Compute 2.5% Zakat With Asset Breakdown
Compute your annual Zakat with the latest Nisab value.
Kundali Calculator | Compute Kundali From Birth Details
Generate a Vedic Janma Kundali with Lahiri Ayanamsa.
Featured tools
The most-used online tools on CalcaTools — text utilities, image work, PDFs, code helpers and generators.
Word Counter | Count Words, Characters, Sentences & Reading Time
Real-time word, character and reading-time counter for any text.
Password Generator | Create Strong, Random Passwords Locally
Build strong random passwords with length and symbol controls.
QR Code Generator | Create QR Codes for URLs, Text & Wi-Fi
Generate downloadable QR codes for URLs, vCards, Wi-Fi and more.
PDF Compressor | Reduce PDF size locally without quality loss
Shrink PDF file size in your browser — no upload needed.
JSON Formatter | Format, Validate, and Minify JSON Locally
Format, validate and minify JSON with syntax highlighting.
Color Picker | Pick Colors and Copy HEX, RGB, HSL & CSS Values
Pick colors and copy HEX / RGB / HSL / OKLCH values.
Temperature Converter | Convert Celsius, Fahrenheit & Kelvin
Convert temperatures between Celsius, Fahrenheit and Kelvin.
Image Compressor | Reduce JPG, PNG, and WebP File Size Locally
Compress JPG / PNG images client-side to save bandwidth.
Expert Guides & Insights
Detailed tutorials, calculator breakdowns, and expert explanations of our formulas.
How Tithi (Lunar Day) Is Calculated from Moon–Sun Positions — A Worked Example
How tithi is calculated from Moon–Sun elongation: the 12° rule, the 30 tithi names, why tithi lengths vary, and a worked Lahore example with real numbers.
Shubh Muhurat vs Rahu Kaal: How the Timings Are Actually Derived — A Worked Example
How Rahu Kaal and shubh muhurat timings are derived: the weekday-segment rule, the Abhijit muhurta rule, and a worked Lahore example with real numbers.
How the Kundli Matching Score (Guna Milan) Is Calculated — A Worked 36-Point Example
How kundli matching (guna milan) works: all 8 kootas and the 36-point table explained, plus a fully worked Rohini x Mrigashira example scored step by step.
Islamic Inheritance Shares (Faraid) — A Worked Example for Beginners
How Islamic inheritance (faraid) works: fixed shares, the 2:1 rule, debts and bequests settled first — with a fully worked Rs 12 million example explained.
Live market prices
Track crypto, stocks, indices, commodities and forex in one clean live board — auto-updating, free, no signup.
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Prices are indicative, may be delayed up to ~15 minutes, and are for information only — not financial advice. Crypto data by CoinGecko; equities/indices by Yahoo Finance.
Why use CalcaTools
Trusted by thousands of users for everyday calculations — built by people who actually use the tools.
Expert-reviewed formulas
Health, finance, religious and astronomical formulas are reviewed by a named in-house panel and re-checked every quarter.
100% private, in-browser
Every calculation runs client-side. Your inputs never leave your device — no accounts, no logs, no third-party sharing.
Fast and responsive
Compiled CSS, lazy fonts, no Tailwind CDN — every page loads in under a second on a 4G phone connection.
Cited sources, full methodology
Each tool documents the exact formula and links to an authoritative source — CFPB, WHO, NIST, ISKCON, Hilal Committee, and more.