Calculators

Select your ceremony style, guest count, cuisine grade, and attire level to estimate total wedding costs and expected gift money. See your out-of-pocket amount at a glance—helpful for budgeting before venue visits.

Instantly compare unit prices across products with different sizes and quantities. Supports 11 units (ml, g, kg, L, pieces, sheets, etc.) and up to 5 items side by side to find the best deal.

Calculate tax savings from offsetting capital gains and dividend income against capital losses (Songeki Tsūsan). Supports 3-year loss carryforward for Japanese stock and investment fund taxes.

Estimate your Japanese pension (nenkin) benefits by entering National Pension and Employee Pension enrollment months and average salary. Instantly see projected monthly amounts at any age from 60 to 75, including early and deferred receipt adjustments. Compare how much more you receive by waiting. Free, private — all calculations run in your browser.

Calculate volume from dimensions, get cement, sand, gravel and water quantities plus estimated cost. Supports mortar mix and ready-mix alerts.

Instantly calculate lottery winning probability and expected value. Simply enter the number of tickets, winning odds (1/N format), prize amount, and ticket price to get multiple statistical insights. Beyond basic probability, expected value, and return rate, this tool provides ROI rating compared to industry standard (45-47%), calculates Japanese tax implications for high winnings, and determines how many tickets are needed to reach 50% probability. A purchase quantity comparison table is also displayed to help plan your strategy. All data is processed entirely in your browser for maximum privacy.

Compare up to 4 alcoholic beverages simultaneously using the industry-standard price per 100ml of pure alcohol to find the best value. Simply enter the price, volume, and alcohol percentage for any drinks — beer, wine, sake, shochu, whiskey, spirits, and more — to instantly calculate the cost per 100ml of pure alcohol and cost per liter. Visual bar graphs make multi-product comparison results clear at a glance. All calculations are performed entirely in your browser, with no data sent to any server.

An online calculator for Japanese automobile tax (jidousha-zei shubetsuwari). Simply enter your engine displacement, fuel type, and first registration year to instantly calculate the annual tax amount, including age surcharges and green tax incentives (eco-car discounts). Supports kei cars and electric vehicles.

Calculate gas costs and fuel consumption instantly by entering distance, fuel efficiency, and gas price. Supports round-trip and multi-segment totals — a free online tool perfect for estimating driving and commuting expenses in Japan.

Calculate Japanese maternity and childcare leave benefits by entering your due date and monthly salary. Automatically computes maternity allowance (Shussan Teatekin), childcare leave benefits at 67% for the first 180 days and 50% thereafter, and estimated social insurance premium savings during leave. Supports up to 24 months of childcare leave with upper and lower limits applied automatically. Also includes support for partner post-birth paternity leave benefits, consolidating multiple benefit streams in one calculation. Get a clear overview of total benefits from maternity leave through childcare leave for family financial planning. When your salary exceeds the ceiling limits, the tool displays notices about salary cap adjustments to insurance premium exemptions. All calculations are performed entirely in your browser — no personal information is ever sent to a server.

Estimate licensed nursery school fees for one child or multiple children using household income. Supports multi-child discounts (50% for 2nd, free for 3rd+) and the free-for-ages-3–5 policy.

A free online margin calculator that instantly computes gross margin percentage, markup percentage, and profit amount from cost and selling price. Ideal for product pricing, procurement negotiations, and profitability analysis. Supports optional additional costs such as shipping, taxes, and fees to calculate net profit margin. Runs entirely in your browser — no data is sent to any server. Fast, safe, and always available.

Instantly calculate tips and split bills. Enter the bill amount and tip percentage to see totals and per-person amounts. Includes quick-select buttons for common tip percentages.

Enter room dimensions and tile size to instantly calculate the number of tiles, cases, and spare tiles needed. Grout width and overage percentage are fully accounted for.

Convert between annual, monthly, weekly, and daily interest rates with support for both compound and simple interest calculations. Enter a rate and period type to instantly see all equivalent rates. Includes copy-to-clipboard for easy result sharing. Perfect for comparing loan APRs, investment yields, and credit card rates. All calculations run entirely in your browser with no server data transfers.

Calculate Japanese resident tax (municipal and prefectural tax) by entering your annual income and deductions. Supports both salaried employees and self-employed individuals. The tool separately displays the income-based portion (10% of taxable income: 6% municipal + 4% prefectural) and the flat-rate portion (5,000 yen/year: 3,500 municipal + 1,500 prefectural). It factors in major deductions including basic deduction, social insurance, life insurance, spouse, dependents, and disability. Adjustment deduction (調整控除) is automatically calculated to account for differences between income tax and resident tax personal deductions. Monthly estimated amounts help with take-home pay planning and household budgeting, especially useful for Furusato Noto (hometown tax donation) planning. All calculations run entirely in your browser — no income data is ever sent to a server.

Enter each appliance's wattage (W) and daily usage hours to automatically calculate daily, monthly, and yearly electricity costs. Register multiple appliances to see total costs, and adjust the rate per kWh to compare plans.

Easily calculate Japanese withholding income tax (源泉徴収税額) deducted from salary, bonuses, and freelance payments. Supports three calculation types: Column A (甲欄, standard employee with declaration), Column B (乙欄, no declaration filed), and freelance payments (10.21% up to 1M yen, 20.42% over 1M yen). Factors in number of dependents for accurate tax amounts. All processing is done entirely in your browser — no data is sent to any server.

Select both parents' blood types (A, B, O, AB) to calculate the probability of each possible blood type for their child based on Mendelian genetics. Probabilities are displayed as percentages with visual bar graphs. An educational tool for understanding blood type inheritance. All processing is browser-based — no data is sent to any server.

Enter parent heights to instantly predict your child's adult height using two formula methods, displayed separately for boys and girls. All data is processed in your browser for complete privacy.

Estimate your Blood Alcohol Concentration (BAC) in real-time using the Widmark formula. Enter the drinks you consumed, your weight, gender, and elapsed time. Results include drive safety indication, intoxication level, and estimated time to sober up. All processing happens in your browser.

Instantly calculate wind chill temperature by entering air temperature and wind speed. Computes using both the Missenard formula and Linke formula, with cold level assessment (comfortable, slightly cold, cold, very cold, dangerous). Useful for cold weather preparation and outdoor activity planning.

Instantly calculate Body Surface Area (BSA) using three formulas by entering height and weight. Compare results from Du Bois, Shintani (Japanese-optimized), and Mosteller formulas. Useful for drug dosage calculations, medical assessments, and sports science body composition analysis. All processed in your browser.

Calculate your daily protein, fat, and carbohydrate targets in grams based on your calorie goal and preferred macro ratio. Includes presets for fat loss, muscle gain, and balanced eating.

Enter the temperature and humidity to find out how hot it actually feels. The Discomfort Index combines heat and moisture into a single number rated across 8 comfort levels, from 'Cold' to 'Extremely Uncomfortable.' At DI 75 about 9% of people feel uncomfortable; at 77 that jumps to 65%. Helpful for heatstroke prevention, choosing what to wear, and setting your AC. Color-coded results make the answer obvious at a glance.

Instantly calculate the Rohrer Index from a child's weight and height, displaying 5-level classifications with color-coded results. View BMI values simultaneously for comparison, making body composition assessment more accurate during growth periods. The Rohrer Index is the standard metric in Japanese school health programs and more suitable for growing children than adult BMI. All processing happens in your browser with complete privacy protection.

Instantly calculate predicted lung capacity (vital capacity) in mL by entering age, gender, and height. Uses gender-specific formulas and displays %vital capacity assessment (80% or above is normal). Useful as a respiratory function reference. All calculations are processed entirely in your browser.

Instantly calculate the number of working days (weekdays) in a given period by entering start and end dates. Also displays total calendar days, weekend days, and separate counts for Saturdays and Sundays. Ideal for project estimation, payroll calculation, and work schedule planning. All calculations are performed entirely in your browser — no data is ever sent to a server.

Calculate elapsed time between two dates with detailed breakdown in years, months, days, hours, minutes, and seconds in real-time.

Calculate elapsed time instantly by entering start and end times. Displays results in hours:minutes, total minutes, and two decimal formats: precise decimal hours and labor-law-compliant 15-minute block rounding. Perfect for payroll, timesheet entry, and compliance tracking. Automatically handles overnight shifts. All processing is done locally — no data transmission.

Real-time countdown showing remaining days, weeks, hours, minutes, and seconds until your target date. Perfect for tracking time until events, anniversaries, exams, or travel dates. Also calculates elapsed time for past dates. All processing happens in your browser — no data is ever sent to any server.

A free online tool for instant conversion between major ratio and proportion units including percent (%), per mille (‰), ppm, ppb, ppt, decimal, and traditional Japanese units (wari, bu, rin). Simply enter a value and select the source unit to see conversion results for all supported units in a clear table. Covers everything from ppm/ppb/ppt used in chemical analysis and environmental monitoring to wari/bu/rin used in Japanese baseball batting averages and financial interest rates. Runs entirely in your browser with no installation required. Adjustable decimal precision (2-8 places) accommodates both high-precision scientific work and general financial calculations. Perfect for scientific research, quality control, statistical analysis, and financial calculations.

Free online frequency converter for Hz, kHz, MHz, GHz, THz, mHz, rpm, rad/s, and BPM. Enter a value and select the source unit to instantly see all equivalent frequency values in a single table. Perfect for electronics design, motor speed verification, acoustics, and engineering calculations in your browser.

Sound Level Converter is a free online calculator for converting between dB SPL, Pa, μPa, phon, and sone. Enter a number and choose the source unit to instantly see equivalent values in all supported units in a single table. It is useful for acoustics study, interpreting sound meter data, reading speaker specifications, and educational estimates, and it runs entirely in the browser with no installation required. Because dB is logarithmic, it does not scale linearly with Pa. This tool uses the 20 μPa reference pressure for SPL and common approximations for phon and sone. Even when magnitudes differ by many orders, the tool keeps the output readable so you can move quickly from rough comparison to documentation or design work.

A free online tool for instant conversion between major density units including kg/m³, g/cm³, g/L, kg/L, mg/mL, lb/ft³, lb/in³, oz/in³, and t/m³. Simply enter a value and select the source unit to see conversion results for all supported units in a clear table. Perfect for physics, chemistry, materials engineering, food science, and any field requiring accurate density unit conversion. Compare densities of water, metals, gases, and other substances with precision. Runs entirely in your browser with no installation required.

Simplify and find common denominators for fractions online with ease. In simplification mode, enter numerator and denominator to automatically reduce using GCD. In common denominator mode, enter two fractions to find the common denominator using LCM. Detailed calculation steps (Euclidean algorithm) are shown for educational purposes. All processing happens entirely in your browser.

One-click calculator for permutations, combinations, and their repeated variants. Enter n and r to compute P(n,r), C(n,r), n^r, and H(n,r) instantly with formulas. Free tool for probability, statistics education, exam prep, programming problems, and combinatorics challenges.

Calculate circle measurements in real-time with full unit support (mm, cm, m). Enter any single value and get all measurements instantly: area, circumference, radius, and diameter. Adjust decimal precision, view the formula used, and copy results with one click. All processing happens in your browser.

Calculate travel time from distance and speed online. Displays results in hours:minutes:seconds format. Includes preset speeds for walking, cycling, driving, and bullet train. Features reverse calculation modes (time + speed → distance, distance + time → speed). All processing happens entirely in your browser.

Free Japanese name fortune calculator analyzing the Five Grids (Gokaku) based on kanji stroke counts.

Calculate fuel costs instantly by entering distance, fuel efficiency (km/L), and gas price per liter. Also features a reverse mode to calculate how far you can drive on a given amount of fuel. Ideal for trip budgeting, commute cost planning, and comparing fuel costs between vehicles. Designed for drivers in Japan with support for current Japanese fuel prices.

Paste your text to instantly calculate reading time, character count, word count, and estimated pages. Supports both Japanese and English with preset speeds (slow, normal, fast) and adjustable slider.

Enter a win rate and number of trials to instantly calculate the odds of consecutive wins or hitting at least once. Results shown as a table and chart—great for gacha odds, lottery analysis, and probability homework.

The ultimate gacha calculator for mobile games. Enter a drop rate and pull count to instantly see your odds, expected value, and cost. Features a constellation simulator with Genshin Impact, Honkai Star Rail, and FGO presets — run 10,000 Monte Carlo simulations to find median pulls, cost, and lost 50/50 count for C0 through C6. Custom mode supports any game. Includes a luck checker, probability curve graph, reverse calculator, and cumulative table. Free, private, runs in your browser.

Calculate how many tries and how much money it takes to collect every item from a capsule toy machine, blind box, or prize draw where all items have equal odds. Enter the number of types to instantly see the expected pulls and cost. Features include a reverse calculator ('How many pulls for a 90% chance of completing?'), a probability curve graph, and a stage-by-stage table showing why the last item is always the hardest. For social game gacha with variable drop rates, see our Gacha Probability Calculator. Free, runs entirely in your browser.

Free coin flip probability calculator using binomial distribution formula C(n,k)×(0.5)^n. Instantly compute exact probabilities for any number of coin tosses and desired heads outcomes.

What are the odds of rolling a 7 with two dice? Enter the number of dice and your target sum to get the exact probability plus a full distribution table. Great for D&D, tabletop RPGs, and board games. Calculations are precise (no simulation) and run entirely in your browser.