JSON to CSV Converter
Paste JSON and instantly export a clean CSV file — no upload required.
Open Tool
Simple Online Tools.
Built for Everyday Problems.
Fast calculators, converters, and utilities — no login, no clutter.
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🧑💻 Developer Tools
View allRegex Tester
Test and debug regular expressions with live match highlighting on the fly.
Open ToolColor Converter
Convert between HEX, RGB, HSL, and more colour formats instantly.
Open ToolUnix Timestamp Converter
Convert epoch timestamps to dates and see any moment across 30+ world timezones instantly.
Open Tool🏠 Home Calculators
View allPaint Calculator
Calculate exactly how many litres of paint you need for any room.
Open ToolTile Calculator
Work out how many tiles you need based on area and tile size.
Open ToolConcrete Volume Calculator
Estimate concrete volume for slabs, columns, and footings in seconds.
Open Tool🐾 Pet Tools
View allDog Feeding Calculator
Get a daily food portion recommendation based on your dog's weight and age.
Open ToolCat Age Calculator
Convert your cat's age into human years with a single click.
Open ToolPet Weight Estimator
Estimate a healthy weight range for your dog or cat breed.
Open Tool📊 Finance Tools
View allLoan EMI Calculator
Calculate your monthly EMI for any loan amount, interest rate, and tenure.
Open ToolTip Calculator
Split a bill and calculate tips in seconds — great for group dining.
Open ToolCurrency Converter
Convert 160+ world currencies with live exchange rates, updated every 6 hours.
Open Tool🎓 Student Tools
View allVTU SGPA Calculator
Calculate your VTU SGPA for 2021, 2022 & 2025 schemes. Pick your branch, semester and get your SGPA instantly.
Open ToolVTU CGPA Calculator
Enter your semester SGPAs and calculate your overall VTU CGPA — with a personalised congratulations message.
Open ToolPomodoro Timer
Stay focused with 25-min work sessions, short & long breaks, session dots, and sound alerts.
Open Tool❤️ Health Tools
View allBMI Calculator
Calculate your Body Mass Index and see your healthy weight range for your height.
Open ToolHeight Predictor Calculator
Predict likely adult height using Mid-Parental, Khamis-Roche, and Bone Age methods.
Open ToolOvulation Calculator
Predict your ovulation date and fertile window based on your cycle length.
Open ToolWater Intake Calculator
Find out how much water you should drink daily based on weight and activity level.
Open ToolSleep Cycle Calculator
Find the best times to wake up aligned to your natural 90-minute sleep cycles.
Open Tool🎮 Brain & Reaction Games
View allF1 Reaction Time Test
Simulate the Formula 1 race-start lights sequence and test your reflexes like a pro driver.
Play NowReaction Time Test
Classic 5-round benchmark — click when green and measure your reaction time in milliseconds.
Play NowAim Trainer
Click 20 targets as fast and accurately as possible. Train your mouse aim and hand-eye coordination.
Play NowMemory Sequence Game
Simon-style colour sequence memory challenge. How many rounds can your brain handle?
Play NowCPS Test
Measure your clicks per second over 5, 10 or 15 seconds. See how you compare to pro gamers.
Play NowFree Online Tools for Every Everyday Problem — civvy.tech
civvy.tech is a growing collection of free, fast, and no-login online calculators and utilities built for people who want quick, accurate answers without downloading an app or wading through cluttered, ad-heavy websites. Whether you're a developer debugging code, a student calculating your SGPA, a homeowner planning a renovation, or someone trying to better understand their health — civvy.tech has a tool built for you.
Health & Wellness Calculators
Our Health Tools category is designed for anyone who wants to make more informed decisions about their body and wellbeing. The BMI Calculator gives you your Body Mass Index, category, and healthy weight range in both metric and imperial units. The Height Predictor Calculator helps estimate likely adult height using Mid-Parental, Khamis-Roche, and Bone Age frameworks. The Ovulation Calculator helps you predict your fertile window and cycle dates based on your last period and cycle length. The Water Intake Calculator gives you a personalised daily hydration target based on your weight, activity level, and climate. And the Sleep Cycle Calculator uses the science of 90-minute cycles to help you wake up refreshed, not groggy.
Developer Utilities
Our Dev Tools are built for speed and daily use. The JSON to CSV Converter processes any JSON array client-side and outputs a clean downloadable CSV — no server upload needed. The Regex Tester provides live match highlighting with full support for all JavaScript regex flags, perfect for writing and debugging patterns on the fly. The Color Converter converts between HEX, RGB, and HSL instantly with a live preview. And the Unix Timestamp Converter decodes epoch time across 30+ world time zones in one click.
Home Improvement Calculators
Planning a home project? Our Home Calculators help you estimate materials accurately and avoid costly over- or under-ordering. The Paint Calculator works out exactly how many litres of paint you need for any room, accounting for coats, windows, and doors. The Tile Calculator gives you a count of tiles needed plus a 10% waste buffer. (See how much extra tile you need to buy) And the Concrete Volume Calculator handles slabs, footings, and columns in m³, with an overage recommendation.
Finance & Money Calculators
Our Finance Tools cover the most common personal finance calculations. Use the Loan EMI Calculator to see your monthly repayment, total interest cost, and total amount paid for any loan — home, car, personal, or education. The Tip Calculator splits bills and calculates tips for any group size instantly. And the Currency Converter supports 15 major currencies for quick travel and international shopping estimates.
Pet Health Tools
Our Pet Tools are designed to help dog and cat owners make better decisions about their pet's nutrition and health. The Dog Feeding Calculator gives daily food portion recommendations based on your dog's weight, age, and activity. The Cat Age Calculator converts cat years to human years using a non-linear growth model. And the Pet Weight Estimator shows the healthy weight range for 25+ popular breeds.
VTU Student Tools
Built specifically for Visvesvaraya Technological University students, our Student Tools include a VTU SGPA Calculator that supports the 2021, 2022, and 2025 scheme regulations across all branches and semesters, a VTU CGPA Calculator that tracks your overall academic performance across semesters, and a Pomodoro Timer with customisable work and break intervals, session tracking, and sound alerts — ideal for exam prep.
Brain & Reaction Games
Our Brain & Reaction Games are free online tools to test and improve your cognitive performance. The F1 Reaction Time Test simulates the Formula 1 race-start lights sequence to test your reflexes under pressure. The Reaction Time Test is a classic 5-round human benchmark that measures your average and best response time in milliseconds. The Aim Trainer challenges your mouse accuracy, click speed, and hand-eye coordination across 20 shrinking targets. The Memory Sequence Game is a Simon-style working memory challenge that gets progressively faster. And the CPS Test measures how many clicks per second you can sustain over 5, 10, or 15 seconds.
Why civvy.tech?
Every tool on civvy.tech is completely free, works instantly in your browser, and requires no account, no email, and no personal data. Pages are fast-loading, mobile-friendly, and built with clean, accessible HTML. We believe the best tools are the ones that get out of your way — give you what you need and nothing more. Use our tool search to find any calculator instantly, or explore any category from the navigation above.
FAQ
Frequently Asked Questions
Quick answers about civvy.tech and how our tools work.
Are all tools on civvy.tech free?
Yes — every single tool is 100% free. There is no subscription, no premium tier, and no hidden charges. We are funded by minimal non-intrusive advertising, not by paywalling tools.
Do I need an account or login to use the tools?
No account needed. All tools run instantly in your browser. Just open the page and start using it — no sign-up, no email address, no password.
Is my data safe? Do you store what I type in?
Your data never leaves your device. All calculations are processed entirely in JavaScript running locally in your browser. We do not collect, store, or transmit any values you enter into the tools.
What kinds of tools does civvy.tech offer?
We offer free tools across seven categories: Health Tools (BMI, height predictor, water intake, sleep cycles, ovulation), Dev Tools (JSON to CSV, Regex Tester, Color Converter, Timestamp), Home Calculators (paint, tile, concrete), Finance Tools (loan EMI, tip splitter, currency), Pet Tools (dog feeding, cat age, breed weight), Student Tools (VTU SGPA/CGPA, Pomodoro timer), and Brain & Reaction Games (F1 reaction test, reaction time benchmark, aim trainer, memory sequence, CPS test).
Do the tools work on phones and tablets?
Yes. Every tool on civvy.tech is fully responsive and tested on mobile devices. The layouts adapt cleanly to small screens so you get the same experience on a phone as on a desktop.
How accurate are the calculators?
Our calculators use standard, widely accepted formulas from sources like the WHO, NHS, and EFSA. They are accurate for general estimation and informational purposes. For medical, financial, or structural decisions, always follow up with a qualified professional.
Can I request a new tool?
Absolutely! We’re always looking to add useful tools. Head to our Contact page and drop us a message with your idea.