Calculator & Life Tools
Loan, savings, tax, and net-salary calculators, unit and currency converters, BMI/calories, D-day, trip cost splitting, and more for everyday life and work.
53 tools
Korean Car Tax
Compute annual Korean car tax and local education tax from engine displacement and vehicle age. Supports sedans, business vehicles, hybrids, and EVs.
Severance Pay Calculator
Estimate Korean statutory severance pay from tenure, average wage, bonus, and unused leave. Useful before resignation, retirement, or comparing DB vs DC pension schemes.
Korean Income Tax
Estimate Korean comprehensive income tax from gross income, expenses, and deductions. For May tax-filing season self-checks, freelance/rental income estimates.
Real Estate Tax (KR)
Compute Korean acquisition, transfer, and property taxes โ single vs multi-home, holding period, capital gain progressive rates, and standard-value property tax.
Pomodoro Timer
25-min focus + 5-min break cycles for productivity. Long break every 4 cycles, sound + browser notifications, cycle statistics.
Trip Cost Split
Split travel or dining expenses among members with minimum-transfer settlement. Per-expense partial sharing, greedy optimization.
Loan Calculator
Compute monthly payment and total interest under three Korean repayment methods: equal payment (์๋ฆฌ๊ธ๊ท ๋ฑ), equal principal (์๊ธ๊ท ๋ฑ), and bullet (๋ง๊ธฐ์ผ์์ํ). Useful for mortgage (LTV) simulations, Jeonse loans, credit loans, and car installment comparisons.
Savings ยท Deposit Calculator
Calculate maturity for Korean installment savings (์ ๊ธ) and term deposits (์๊ธ) under simple or compound interest. Auto-deducts 15.4% interest tax with a tax-free option. Useful for comparing Youth Leap Account, ISA, and regular savings, simulating bank products, and planning lump-sum goals.
Net Salary (Korea)
From your gross annual salary, deduct national pension, health insurance, employment insurance, income tax, and local tax to get monthly take-home pay. Supports dependents, children, and non-taxable items. Useful for offer evaluation, job-change comparisons, budgeting, and negotiation prep (2026 rates).
GPA Calculator
Enter courses, grades, and credits to compute GPA, with conversions across 4.5, 4.3, 4.0, and 100-point scales. Handles P/NP and retakes. Useful for end-of-semester self-check, US grad school applications, and scholarship prep.
Pyeong โ mยฒ Converter
Convert precisely between Korean pyeong (ํ, traditional area unit) and square meters. Includes presets for common apartment sizes and an exclusive-use area estimate. Useful for property listings, moving comparisons, furniture planning, and interior quotes.
Graphing Calculator
Plot y = f(x) functions interactively on a 2D canvas. Multiple functions with colors, drag to pan, scroll to zoom, and live cursor coordinates.
Formula Builder (Buttons)
Build math formulas by clicking buttons โ fractions, radicals, integrals, sums, matrices, Greek letters. Live KaTeX preview plus copyable LaTeX source.
Periodic Table
All 118 elements from Hydrogen to Oganesson โ Korean and English names, atomic mass, electron configuration, melting/boiling points, and electronegativity. Search by Korean name, English name, symbol, or atomic number.
Time Calc
Add or subtract time from a time of day, or calculate the difference between two times. Supports both 24h and 12h notations. Useful for predicting meeting end times, flight arrivals, work-hour reconciliation, and combining cooking timers.
Hourly โ Monthly Wage
Convert between hourly, daily, weekly, monthly, and annual wages based on Korea's 40-hour workweek (209 hours/month including weekly holiday allowance). Shows comparison to the Korean minimum wage. Useful for part-time/contract pay, freelance rate setting, and comparing job posting salaries.
Due Date
Estimate due date, current pregnancy week, and trimester from last menstrual period (LMP) or conception date โ based on Naegele's rule. Useful for a rough first estimate before your first OB visit, tracking weekly changes, and planning for delivery.
Scientific Calc
Supports trig, logs, powers, square roots, and other engineering/science calculations. Expression-based input handles long chained calculations. Useful for math/physics/engineering students, engineers, exam prep, and quick statistics.
Percent Calc
All percentage calculations in one screen: N% of X, what percent X is of Y, percent change from X to Y, and X increased or decreased by N%. Useful for revenue change rates, test scores, weight changes, stock returns, and everyday percent math.
Discount Calc
Calculate discounted price from original and rate, find the rate from two prices, or reverse-calculate the original. Useful for checking sale prices, member discounts, stacking card-instant + coupons, and setting up store price tags.
VAT Calc
Auto-calculate supply price (๊ณต๊ธ๊ฐ์ก), VAT, and total at Korea's standard 10% rate. Also reverse-calculates supply price from a VAT-inclusive total. Useful for invoices, tax receipts, audit reviews, VAT filing, and unit-price setting.
BMI Calc
Calculate BMI from height and weight, classified by WHO Asia-Pacific standards: underweight, normal, overweight, and obese. Useful for pre-diet self-checks, interpreting health screening results, insurance prep, and setting target weights.
Compound Interest
Enter principal, rate, and term to compute maturity with compounding. Supports lump-sum deposit and monthly contribution modes. Useful for retirement modeling, education savings plans, long-term return estimates, and simple-vs-compound comparisons.
World Time
See current time in Seoul, Tokyo, New York, London, Paris, Sydney, and more major cities at once. Add/remove cities with real-time updates. Useful for travel and overseas business trips, scheduling video meetings, calling friends/family abroad, and global collaboration.
Random Name Picker
Randomly pick N items from a list. Great for choosing dinner spots, selecting presenters, draw winners, forming class/club teams, and ordering game turns. Powered by Web Crypto for genuinely random, fair results.
Caffeine Tracker
Add up today's caffeine from coffee, tea, and energy drinks, and compare against the 400mg adult daily limit. Useful for cutting back on coffee, gauging dependence, monitoring safe pregnancy intake, and analyzing sleep impact.
Zodiac Sign
Enter your birthday to find your Western 12-sign zodiac, its period, and personality traits. Useful for friend/partner gift inspiration, fun personality readings, and SNS profile zodiac labels.
Chinese Zodiac
Show the Chinese zodiac animal (rat, ox, tiger, rabbit...) and heavenly stem from birth year. Useful for new-year greetings, holiday cards, saju/compatibility inputs, and checking a child's birth-year sign.
Alcohol Converter
Convert alcohol amounts across drink types โ soju, beer, wine, whiskey, and more โ for equivalent comparison. Useful for gauging your limit at hweshik, calculating sober-up time, and comparing drinks.
BMR Calc
Calculate BMR and activity-adjusted TDEE from gender, age, height, and weight โ your baseline calories for cutting or bulking. Useful for meal planning, exercise dosing, and diagnosing weight plateaus.
Running Pace
Enter any two of distance, time, or pace to get the third. Includes finish time predictions for 5K, 10K, half, and full marathon.
Tip Calc
Enter bill total, tip rate, and party size to get per-person share. For US/EU restaurants.
Unit Price Compare
Compare prices of two products of different sizes per unit (100ml, 100g, etc.) to see which is cheaper.
Dice / Coin
Roll various dice (D4, D6, D8, D10, D12, D20, D100) and flip coins. For board games, TRPGs, and decisions.
Rock Paper Scissors
Play rock paper scissors against the computer. Win rate stats included.
Public Holidays
See US federal holidays for this and next year at a glance. Includes floating holidays like Thanksgiving and Memorial Day, computed automatically.
Lunch Picker
Use the roulette when you can't decide. Preloaded Korean/Chinese/Japanese/Western categories, or add your own menus.
Baseball ERA/AVG
Calculate pitcher ERA, hitter batting average, OBP, SLG, and OPS instantly. For amateur baseball and watching games.
Book Reading Time
Estimate how long it'll take to finish a book based on total pages and your reading speed. Uses average Korean reading speed.
Exchange Rate
Enter the rate manually and convert KRW to various currencies or vice versa. Useful for travel budgeting, overseas shopping conversions, and foreign remittance amounts.
Statistics
Enter a list of numbers to get mean, median, mode, standard deviation, variance, quartiles (Q1, Q3), range, and sum in one go. Useful for homework and papers, test score analysis, survey results, and experiment data.
Car Fuel Cost
Calculate driving cost from fuel efficiency (km/L) and gas price. Useful for monthly commute fuel cost, trip fuel estimates, car model comparisons (savings from better mileage), and carpool cost splitting.
Korean Lease Convert
Convert jeonse deposits to monthly rent and back using the conversion rate. Useful for comparing upfront deposit costs when moving, evaluating jeonse vs monthly rent options, and partial deposit + monthly hybrid plans.
Sleep Time
Find optimal wake or bed times based on 90-minute sleep cycles. Useful for deciding nap length after a late shift, optimal bedtime before a morning exam or interview, and jet lag planning.
Blood Donation
Calculate the next eligible donation date based on Korean Red Cross standards using your last donation date and type. Useful for regular donor scheduling, blood donation certificate collection plans, group donation events, and multi-type donation intervals.
Installment Calc
Calculate monthly payment and total fees from principal, rate, and term. Useful for checking affordability before big purchases (appliances, furniture, travel), comparing interest-free installments vs lump sum, and comparing fees across cards.
US Phone Formatter
Normalize phone numbers of any format to a clean US standard like (XXX) XXX-XXXX. Useful for cleaning up Excel/CRM/contact data, handling area codes, and converting to international +1 format.
Korean Biz Number
Validate the checksum of Korea's 10-digit business registration number. Useful for verifying counterparty info, checking before issuing tax invoices, B2B system data integrity, and first-pass risk checks.
Korean RRN
Validate the checksum of a 13-digit Korean Resident Registration Number and extract birth date, gender, and foreigner status. All processing stays in-browser for safety. Useful for form validation, auto-fill UI prototyping, and quickly checking your own RRN digits.
Family Kinship
Enter paternal/maternal relations to see the exact degree of kinship and Korean honorifics (gomo, imo, dangsuk, etc.). Useful for sorting out tricky honorifics at holidays, preparing wedding/funeral greetings, and family tree writing.
Number Format
Convert large numbers to formats like commas (1,000,000), Korean units (100๋ง/1 million), underscores (1_000_000), or scientific (1.0e6). Useful for reports, data tables, readability, receipts, and invoices.
Star Rating
Convert scores to star (โ ) emoji and copy as text. Half-stars supported. Useful for blog reviews, SNS rating posts, email signatures, and presentation slides.
Golf Handicap
Estimate USGA-style handicap from recent round scores. Useful for self-assessing skill, matching handicaps with partners, setting friendly round betting bases, and tracking seasonal skill changes.