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The answer you need, now.
Free online calculators and tools
Use 30 browser tools plus 3 replayable games for calculations, documents, development, writing, and planning. No account needed.
Age CalculatorFind your exact age and the days until your next birthday.Percentage CalculatorCalculate percentages, change rates, and discounted prices.Unit ConverterConvert measurement, speed, and digital storage units instantly.Date CalculatorCount days between dates or add and subtract time.Image CompressorResize, compress, and convert images to JPG, PNG, or WebP.
All 30 tools in one place
Search by name or task, or narrow the list by category. Your inputs stay in your browser whenever possible.
30 tools
Age Calculator
Find your exact age and the days until your next birthday.
Percentage Calculator
Calculate percentages, change rates, and discounted prices.
Unit Converter
Convert measurement, speed, and digital storage units instantly.
Date Calculator
Count days between dates or add and subtract time.
Image Compressor
Resize, compress, and convert images to JPG, PNG, or WebP.
Loan Calculator
Estimate monthly payments and total interest for a fixed-rate loan.
Compound Interest Calculator
Project growth from principal, contributions, and compounding.
Word Counter
Count words, characters, sentences, paragraphs, and reading time.
QR Code Generator
Turn a link or text into a QR code and download it as PNG.
Password Generator
Create strong random passwords locally on your device.
Korea Salary Calculator
Convert annual, monthly, and hourly Korean pay with an editable deduction estimate.
Korea Severance Pay Calculator
Estimate Korean severance pay from service dates and the prior three months of wages.
Korea Social Insurance Calculator
Estimate 2026 Korean employee pension, health, long-term care, and employment insurance.
Korea Weekly Holiday Pay Calculator
Estimate Korean paid weekly rest allowance from hourly pay and scheduled hours.
Korea VAT Calculator
Split or add Korean 10% VAT for quotes and invoices.
Pyeong Calculator
Convert square meters and Korean pyeong, or calculate area from dimensions.
Seoul Real Estate Commission Calculator
Estimate Seoul residential brokerage-fee ceilings for sales and leases.
Appliance Electricity Cost Calculator
Estimate appliance energy use and cost from watts and running time.
Korean Lunar Calendar Converter
Convert dates between the Korean lunar calendar and Gregorian calendar.
Korean Lotto 6/45 Number Generator
Generate six unique Korean Lotto 6/45 numbers with secure randomness.
Merge PDF Online
Merge multiple PDFs or save a selected page range as a new file.
BMI Calculator
Estimate adult body mass index and its reference range from height and weight.
Time Zone Converter
Convert a date and time from one world region to another.
Pomodoro Timer
Cycle through focus and break periods while tracking completed sessions.
Random Wheel
Pick one item at equal probability from as many as 100 choices.
JSON Formatter
Validate JSON syntax and convert it to readable or compact output.
Unix Timestamp Converter
Convert seconds or milliseconds between Unix timestamps and dates.
UUID Generator
Generate up to 100 standard UUID v4 values with cryptographic randomness.
Fuel Cost Calculator
Estimate trip fuel use and cost from distance, economy, and local price.
Typing Speed Test
Type a fixed prompt to measure WPM, characters per minute, and accuracy.
Quick to learn, built to replay
Try a puzzle or survive another shooter wave. Your best score stays on this device.
Small tools, clear standards
Explainable results
We show the relevant formula or standard so you can understand the answer.
Built for two languages
Separate Korean and English pages make search, sharing, and reading straightforward.
Frequently asked questions
Is MoaTools free?
Yes. Every current tool and game is free to use without an account.
Do you save what I enter?
Most calculations run only in your browser. Only necessary local values, such as a game high score, are saved on your device.
Can I use a result in an official document?
The tools are useful for everyday reference. For financial, medical, or legal decisions, confirm the result with the relevant authority or a qualified professional.