RubanTools

Foundation Tools

20 free everyday utilities - calculators, date tools, marks %, attendance, password generator, timers and more.

Flip a Coin

Can't decide? Type your question, flip the coin, and let chance settle it. Front = OK, Back = Not OK.

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Basic Calculator

Add, subtract, multiply and divide with full keyboard support, Indian number formatting, and a 5-calculation history.

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Scientific Calculator

Full scientific functions - sin, cos, log, powers, roots, π and more. Respects BODMAS with a proper expression evaluator.

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Age Calculator

Find your exact age in years, months and days. Includes next birthday countdown, zodiac sign, and live seconds ticker.

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Date Difference

Calculate exact days, weeks, months and years between any two dates. Shows weekday and weekend breakdown.

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Date Calculator

Add or subtract days, weeks, months or years to any date. Find deadlines, expiry dates and anniversaries instantly.

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Percentage Calculator

Three modes in one: find X% of a number, find what % one value is of another, or calculate % increase or decrease.

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Discount Calculator

Enter a price and discount % to get the final sale price, or enter two prices to find the percentage off. Two modes, instant results.

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Tip Calculator

Enter your bill, pick a tip %, and split evenly across any number of people. Instant per-person breakdown with optional round-up.

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Password Generator

Generate strong, random passwords using cryptographic randomness. Set length, choose character types, and copy instantly.

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Random Number Generator

Generate one or many truly random numbers in any range using cryptographic randomness. Lottery mode, no-repeats, up to 20 numbers.

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Dice Roller

Roll D4, D6, D8, D10, D12 or D20 - single or multiple dice with instant totals, individual results, and last-5-rolls history.

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Yes or No

Stuck on a decision? Type your question and let cryptographic randomness give you a definitive YES or NO - 50/50 every time.

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Wheel Picker

Add names or options, spin the wheel, and get a random winner. Remove winner mode, shuffle, and up to 30 entries.

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Stopwatch

Precise online stopwatch with lap timer. Start, pause, lap, reset - with keyboard shortcuts and hundredths-of-a-second display.

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Countdown Timer

Set a duration or count down to a specific date and time. Progress bar, presets (1 min to 1 hr), and browser notification on completion.

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Pomodoro Timer

Focus with 25-min work sessions and short breaks. Configurable cycles, SVG progress ring, auto-start, and browser notifications.

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CGPA to Percentage

Convert CGPA to percentage using CBSE (×9.5), Anna University (×10), VTU, or a custom formula. Reverse conversion included.

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Marks % Calculator

Convert marks to percentage with CBSE, ICSE and college grade scales - or find how many marks you need to hit a target percentage.

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Attendance Calculator

Check your attendance %, find how many classes you can skip before hitting 75%, or calculate classes needed to recover - exam eligibility in seconds.

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Related Categories

Health & Fitness

BMI, BMR, calorie, ideal weight, body-fat, blood pressure, diabetes risk (IDRS), cholesterol checker, pregnancy due-date, ovulation and period calculators.

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Financial Calculators

EMI, SIP, FD, RD, PPF, NPS, GST, income tax, HRA, retirement, CAGR, salary, step-up SIP, SWP, NSC, KVP, SSY, gold loan, ULIP, toll, electricity bill, rent vs buy, property ROI and more.

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Unit Converters

Length, weight, temperature, area, volume, speed, energy - including Indian units (ground, cent, bigha, kanal, marla).

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Foundation Everyday Tools

Foundation tools are the everyday calculators and utilities that virtually every internet user needs at some point - from computing a percentage discount while shopping online to calculating how many days are left until an exam. This collection brings together over 20 of the most commonly searched utility tools in India, covering calculations that students, professionals, and households use daily. No installation, no sign-up, and no ads blocking the interface - just clean, fast tools that work on any device.

Tools Designed for India's Digital Citizens

India had over 900 million internet users in 2024, with the majority accessing the web via smartphones. Searches for basic calculators spike during school exam season (February-March for CBSE boards), tax filing season (June-July for ITR), and festival seasons when discounts and budget calculations are common. The tools in this suite - including age calculator, percentage calculator, attendance calculator, discount calculator, and password generator - address the most frequent calculation searches across Indian Google queries.

Why These Tools Exist

While smartphones have built-in calculators, they lack specialist functions - they cannot tell you your exact age in days, calculate whether your attendance is above the required 75% for college, or generate a secure 16-character password for your IRCTC or DigiLocker account. Each tool in the Foundation suite fills a specific, recurring need that standard phone calculators or spreadsheets handle clumsily. They are designed to give an instant, clearly explained answer with no unnecessary complexity.

Foundation Tools FAQ

Our Basic Calculator is designed for daily use: it supports full keyboard input, displays numbers in Indian formatting (lakh and crore with commas), and keeps a 5-calculation history so you can review your recent results without retyping. For more advanced needs our Scientific Calculator handles sin, cos, tan, log, powers, roots, π and complex expressions using a proper BODMAS expression evaluator - not just button-by-button input. Both calculators run entirely in your browser with no data sent to any server.

Use the Age Calculator on this page: enter your date of birth and it instantly shows your exact age broken down into years, months and days. It also displays a countdown to your next birthday in days, your western zodiac sign based on your birth date, and a live ticking seconds counter showing how many seconds you have been alive. The calculation accounts correctly for leap years and varying month lengths, so the result is always precise regardless of when you were born.

Our Password Generator uses the browser's cryptographic random number API (window.crypto.getRandomValues) which is far more secure than Math.random(). You can set the password length between 8 and 64 characters and choose which character sets to include: uppercase letters (A–Z), lowercase letters (a–z), digits (0–9) and symbols (!@#$%^&* etc.). The generated password is never sent to any server - it is created entirely within your browser. Copy it with one click directly to your clipboard.

The Pomodoro technique, developed by Francesco Cirillo, breaks work into 25-minute focused sessions (called pomodoros) separated by 5-minute short breaks, with a longer 15–30 minute break after every four sessions. This structured rhythm reduces mental fatigue and improves sustained focus. Our Pomodoro Timer features configurable work and break durations, an animated SVG progress ring that fills as time passes, auto-start between cycles, and browser notifications so you know exactly when to stop and resume - even with the browser tab in the background.