Also available in: Português (Brasil) · Español · Français · Deutsch · Italiano · 日本語 · Bahasa Indonesia · Türkçe · ไทย · Tiếng Việt · العربية · हिन्दी · Русский

HELLO, WORLD_

Calculators and data that answer instantly.

Finance

• Currency exchange ratesReference rates for the main currency pairs, updated every business day by the ECB
• World finance atlasGDP, GDP per capita, inflation, unemployment and official exchange rates by country, with World Bank data
• Compound interest calculatorCalculate compound interest growth with monthly deposits. Formula, worked example and growth table by time horizon.
• Loan payment calculatorCalculate your monthly loan or mortgage payment with a full amortization schedule, total interest and payoff insights.
• Inflation around the worldComparative table of 40 countries with average inflation over the last 10 years, the historical peak of each World Bank series and its year, from hyperinflations to deflationary Japan.
• The purchasing power of money in Brazil over timePurchasing power calculator for Brazil: convert amounts between 1980 and 2025 with the World Bank index, see the 2,947.7% peak of 1990 and year by year inflation.
• The purchasing power of money in the United States over timePurchasing power calculator for United States: convert amounts between 1960 and 2024 with the World Bank index, see the 13.5% peak of 1980 and year by year inflation.
• The purchasing power of money in Argentina over timePurchasing power calculator for Argentina: convert amounts between 2017 and 2024 with the World Bank index, see the 219.9% peak of 2024 and year by year inflation.
• The purchasing power of money in Turkey over timePurchasing power calculator for Turkey: convert amounts between 1960 and 2025 with the World Bank index, see the 105.2% peak of 1994 and year by year inflation.
• The purchasing power of money in Mexico over timePurchasing power calculator for Mexico: convert amounts between 1960 and 2025 with the World Bank index, see the 131.8% peak of 1987 and year by year inflation.
• The purchasing power of money in India over timePurchasing power calculator for India: convert amounts between 1960 and 2025 with the World Bank index, see the 28.6% peak of 1974 and year by year inflation.
• The purchasing power of money in Germany over timePurchasing power calculator for Germany: convert amounts between 1960 and 2025 with the World Bank index, see the 7% peak of 1973 and year by year inflation.
• The purchasing power of money in Japan over timePurchasing power calculator for Japan: convert amounts between 1960 and 2025 with the World Bank index, see the 23.2% peak of 1974 and year by year inflation.
• The purchasing power of money in the United Kingdom over timePurchasing power calculator for United Kingdom: convert amounts between 1960 and 2025 with the World Bank index, see the 24.2% peak of 1975 and year by year inflation.
• The purchasing power of money in France over timePurchasing power calculator for France: convert amounts between 1960 and 2025 with the World Bank index, see the 13.6% peak of 1974 and year by year inflation.
• Countries with the highest inflation everWhich country had the highest inflation in history? Ranking of 40 countries by the worst inflation year recorded by the World Bank, from Peru's 7,482% peak to Latin America's hyperinflations.
• Countries with the highest inflation nowWhich country has the highest inflation today? Ranking of 40 countries by the World Bank's most recent annual figure, from Argentina (220%) to the most price stable, with the 10 year average alongside.

Dates

• What happened on each dayThe events of each date of the year: events, births and deaths, curated from Wikipedia
• Age calculatorCalculate exact age in years, months and days from a date of birth, including total months and days lived.
• Days between datesCount calendar days, weekdays and weeks between two dates. Instant tool with a table of common spans.
• Business days calculatorCount business days, weekends and calendar days between two dates in 2026. The tool runs in the browser and keeps holidays separate by design.
• Days until New Year's Day 2026How many days until New Year's Day 2026? The date falls on a Thursday, January 1, 2026. Live countdown plus every date from 2026 to 2030.
• Days until New Year's Eve 2026How many days until New Year's Eve 2026? The date falls on a Thursday, December 31, 2026. Live countdown plus every date from 2026 to 2030.
• Days until Christmas 2026How many days until Christmas 2026? The date falls on a Friday, December 25, 2026. Live countdown plus every date from 2026 to 2030.
• Days until Christmas Eve 2026How many days until Christmas Eve 2026? The date falls on a Thursday, December 24, 2026. Live countdown plus every date from 2026 to 2030.
• Days until Epiphany 2026How many days until Epiphany 2026? The date falls on a Tuesday, January 6, 2026. Live countdown plus every date from 2026 to 2030.
• Days until Halloween 2026How many days until Halloween 2026? The date falls on a Saturday, October 31, 2026. Live countdown plus every date from 2026 to 2030.
• Days until Valentine's Day 2026How many days until Valentine's Day 2026? The date falls on a Saturday, February 14, 2026. Live countdown plus every date from 2026 to 2030.
• Days until Dia dos Namorados 2026How many days until Dia dos Namorados 2026? The date falls on a Friday, June 12, 2026. Live countdown plus every date from 2026 to 2030.
• Days until St. Patrick's Day 2026How many days until St. Patrick's Day 2026? The date falls on a Tuesday, March 17, 2026. Live countdown plus every date from 2026 to 2030.
• Days until April Fools' Day 2026How many days until April Fools' Day 2026? The date falls on a Wednesday, April 1, 2026. Live countdown plus every date from 2026 to 2030.
• Days until Earth Day 2026How many days until Earth Day 2026? The date falls on a Wednesday, April 22, 2026. Live countdown plus every date from 2026 to 2030.
• Days until May Day 2026How many days until May Day 2026? The date falls on a Friday, May 1, 2026. Live countdown plus every date from 2026 to 2030.
• Days until Cinco de Mayo 2026How many days until Cinco de Mayo 2026? The date falls on a Tuesday, May 5, 2026. Live countdown plus every date from 2026 to 2030.
• Days until International Women's Day 2026How many days until International Women's Day 2026? The date falls on a Sunday, March 8, 2026. Live countdown plus every date from 2026 to 2030.
• Days until Juneteenth 2026How many days until Juneteenth 2026? The date falls on a Friday, June 19, 2026. Live countdown plus every date from 2026 to 2030.
• Days until the Fourth of July in 2026How many days until the Fourth of July in 2026? The date falls on a Saturday, July 4, 2026. Live countdown plus every date from 2026 to 2030.
• Days until Tax Day 2026How many days until Tax Day 2026? The date falls on a Wednesday, April 15, 2026. Live countdown plus every date from 2026 to 2030.
• Days until Flag Day 2026How many days until Flag Day 2026? The date falls on a Sunday, June 14, 2026. Live countdown plus every date from 2026 to 2030.
• Days until Patriot Day 2026How many days until Patriot Day 2026? The date falls on a Friday, September 11, 2026. Live countdown plus every date from 2026 to 2030.
• Days until Constitution Day 2026How many days until Constitution Day 2026? The date falls on a Thursday, September 17, 2026. Live countdown plus every date from 2026 to 2030.
• Days until Veterans Day 2026How many days until Veterans Day 2026? The date falls on a Wednesday, November 11, 2026. Live countdown plus every date from 2026 to 2030.

Everyday Math

• Percentage calculatorCalculate X% of a value, what percentage one number is of another, and the percent change between two values.
• Rule of threeSolve simple proportions: if A is to B, then C is to D. With practical examples and the difference between direct and inverse proportion.
• Discount calculatorCalculate the final discounted price and how much you save. Table by discount tier and the traps of stacked discounts.
• Tip calculatorCalculate the tip, the total bill and each person's share. With tipping conventions for the US and abroad.

Business

• Margin and markupCalculate profit, margin and markup from cost and selling price, and understand the difference that trips up even experienced sellers.
• Dimensional weight calculatorCalculate volume, dimensional weight (167 kg/m³ air standard) and the chargeable weight of your freight, and see why light cargo pays as heavy.

World

• The Formula 1 archiveSeasons, drivers, teams and circuits from 1950 to 2025, all cross linked
• Public holidays by country: 2026 calendarsPublic holiday calendars by country for 2026, including Canada, the Netherlands, Romania and dozens more
• US ZIP codes by stateEvery state's ZIP code counts, ranges and counties, from the GeoNames open dataset
• The periodic tableAll 118 elements with mass, density, discoverer and the etymology of each name
• Airports of the worldHow many airports each country has, with codes, cities and elevation, from the OurAirports dataset
• International cricketInternational cricket teams in numbers, ODI and T20I, with World Cup champions
• Brazil's baby namesBrazil's most common names by birth decade, from the IBGE 2010 Census
• Brazilian Serie A 2026: standings and fixturesBrazilian Serie A 2026: standings computed from scores, fixtures by round, results, team stats and open source attribution from openfootball/football.csv.
• Premier League 2025-26: standings and fixturesPremier League 2025-26: standings computed from scores, fixtures by round, results, team stats and open source attribution from openfootball/football.csv.
• La Liga 2025-26: standings and fixturesLa Liga 2025-26: standings computed from scores, fixtures by round, results, team stats and open source attribution from openfootball/football.csv.
• Italian Serie A 2025-26: standings and fixturesItalian Serie A 2025-26: standings computed from scores, fixtures by round, results, team stats and open source attribution from openfootball/football.csv.
• Bundesliga 2025-26: standings and fixturesBundesliga 2025-26: standings computed from scores, fixtures by round, results, team stats and open source attribution from openfootball/football.csv.
• World Cup 2026: match calendar and resultsWorld Cup 2026 with 104 fixtures, 100 scorelines, groups, dates, times and venues from an openfootball source snapshot for fast lookup.
• Sunrise and moon phaseCheck sunrise, sunset, day length, approximate moon age and moon illumination for major world cities, with local browser calculation.
• Country indicatorsCompare countries by population, area, density, capital, currency and recent inflation in one global table with local and World Bank data.
• Korean age calculatorCalculate your Korean age in all 3 systems (international, traditional and year age) and understand the 2023 law that unified legal age in Korea.
• Japanese era converterConvert western years to Japanese eras (Reiwa, Heisei, Showa, Taisho, Meiji), with a landmark year table and the mental math shortcut.
• Tipping around the worldTable of tipping customs in 40 countries: where it is required, where it offends and where it is already on the bill.
• Calendars of the worldThe 12 calendars in use around the world today, with type, where they apply and what year 2026 is in each. In Ethiopia, it is still 2018.
• F1 world championsComplete F1 world champions list, season by season, with driver, team, wins and constructors title. From Farina to Lando Norris.
• Chinese zodiac by yearFind your Chinese zodiac sign and element from your birth year, with the full table from 1924 to 2043 and the Lunar New Year warning (January 21 to February 20).
• Animal gestationTable of gestation for 41 animals in days, from the opossum (~13) to the African elephant (~645), compared with the ~280 human days.
• Average height by countryAverage height of men and women in 42 countries, including Norway, Russia, Ireland and Sweden, with NCD-RisC data and a full comparison table.
• Weird time zonesNepal +5:45, Chatham +12:45, Kiribati +14 (which skipped a day in 1995) and China on a single zone: the strangest time zone cases, sourced from the IANA tzdb.
• Buddhist Era converter (พ.ศ.)Convert Western years to the Thai Buddhist Era (พ.ศ. = year + 543) and back, with a landmark year table and the Sri Lanka, Myanmar, Cambodia and Laos variants.
• Hijri calendar converterConvert dates between the Gregorian and Islamic (tabular Hijri) calendars, see approximate Ramadan and Eid dates from 2024 to 2030 and understand the 354 day lunar year.
• Zakat calculatorCalculate zakat (2.5% of zakatable wealth above the nisab), compare the gold nisab (85 g) with the silver one (595 g) and understand hawl, zakatable assets and school differences.
• World cheese championsThe complete list of World Cheese Awards champions, year by year since 1988, with cheese, producer and country. Gruyère with six titles and every winner verified.
• Bocuse d'Or podiumsGold, silver and bronze from all 20 editions of the Bocuse d'Or, with chef and country, plus the medal table of the France versus Norway duel.
• Best baguette of ParisAll 33 winners of the Grand Prix de la Baguette of Paris, year by year since 1994. The champion supplies the Élysée Palace bread for one year.
• Exoplanets year by yearHow many exoplanets were discovered each year, which method dominated and each season's highlight. 6,319 planets confirmed by NASA.

Codes & Ciphers

• Roman numerals converterConvert numbers to Roman numerals and back, with the full reference table and the subtraction rules explained.
• Number base converterConvert between binary, decimal, hexadecimal and octal in any direction, with a reference table and why each base exists.
• Morse code translatorTranslate text to Morse code and back, with the full alphabet and the story of the code that refuses to die.
• Chess opening statisticsWhite wins, draws and Black wins for the 27 main chess openings, measured across 2,658,585 real games on Lichess.
• Sicilian Defense (1.e4 c5)The Sicilian Defense in real numbers: 45.9% White wins across 388,917 Lichess games, the 5 most common replies, the rating effect and the opening's history.
• French Defense (1.e4 e6)The French Defense in real numbers: 47.8% White wins across 202,192 Lichess games, the 5 most common replies, the rating effect and the opening's history.
• Caro-Kann Defense (1.e4 c6)The Caro-Kann Defense in real numbers: 45.4% White wins across 93,081 Lichess games, the 5 most common replies, the rating effect and the opening's history.
• Italian Game (1.e4 e5 2.Nf3 Nc6 3.Bc4)The Italian Game in real numbers: 50.6% White wins across 88,443 Lichess games, the 5 most common replies, the rating effect and the opening's history.
• Ruy Lopez (1.e4 e5 2.Nf3 Nc6 3.Bb5)The Ruy Lopez in real numbers: 52.1% White wins across 73,519 Lichess games, the 5 most common replies, the rating effect and the opening's history.
• Scandinavian Defense (1.e4 d5)The Scandinavian Defense in real numbers: 49.7% White wins across 111,932 Lichess games, the 5 most common replies, the rating effect and the opening's history.
• Pirc Defense (1.e4 d6)The Pirc Defense in real numbers: 47.8% White wins across 58,616 Lichess games, the 5 most common replies, the rating effect and the opening's history.
• Alekhine's Defense (1.e4 Nf6)The Alekhine's Defense in real numbers: 44.6% White wins across 30,110 Lichess games, the 5 most common replies, the rating effect and the opening's history.
• Scotch Game (1.e4 e5 2.Nf3 Nc6 3.d4)The Scotch Game in real numbers: 52.7% White wins across 40,877 Lichess games, the 5 most common replies, the rating effect and the opening's history.
• King's Gambit (1.e4 e5 2.f4)The King's Gambit in real numbers: 55.0% White wins across 68,798 Lichess games, the 5 most common replies, the rating effect and the opening's history.
• Vienna Game (1.e4 e5 2.Nc3)The Vienna Game in real numbers: 54.1% White wins across 20,015 Lichess games, the 5 most common replies, the rating effect and the opening's history.
• Queen's Gambit (1.d4 d5 2.c4)The Queen's Gambit in real numbers: 54.6% White wins across 154,562 Lichess games, the 5 most common replies, the rating effect and the opening's history.
• Slav Defense (1.d4 d5 2.c4 c6)The Slav Defense in real numbers: 51.3% White wins across 41,842 Lichess games, the 5 most common replies, the rating effect and the opening's history.
• Queen's Gambit Declined (1.d4 d5 2.c4 e6)The Queen's Gambit Declined in real numbers: 52.1% White wins across 45,803 Lichess games, the 5 most common replies, the rating effect and the opening's history.
• King's Indian Defense (1.d4 Nf6 2.c4 g6 3.Nc3 Bg7)The King's Indian Defense in real numbers: 47.5% White wins across 16,082 Lichess games, the 5 most common replies, the rating effect and the opening's history.
• Nimzo-Indian Defense (1.d4 Nf6 2.c4 e6 3.Nc3 Bb4)The Nimzo-Indian Defense in real numbers: 46.0% White wins across 13,554 Lichess games, the 5 most common replies, the rating effect and the opening's history.
• Grünfeld Defense (1.d4 Nf6 2.c4 g6 3.Nc3 d5)The Grünfeld Defense in real numbers: 44.6% White wins across 6,847 Lichess games, the 5 most common replies, the rating effect and the opening's history.
• London System (1.d4 d5 2.Bf4)The London System in real numbers: 51.3% White wins across 18,987 Lichess games, the 5 most common replies, the rating effect and the opening's history.
• English Opening (1.c4)The English Opening in real numbers: 51.2% White wins across 97,752 Lichess games, the 5 most common replies, the rating effect and the opening's history.
• Réti Opening (1.Nf3 d5 2.c4)The Réti Opening in real numbers: 56.5% White wins across 6,918 Lichess games, the 5 most common replies, the rating effect and the opening's history.

Health

• Doctors in the United StatesHow many doctors practice in each US state and in which specialties, from the federal NPPES registry
• Global health atlasPublic health indicators by country, with WHO data
• Skincare and sun protectionUV Index, shade, sunscreen and basic skin care with WHO and CDC sources
• Mental health and well-beingSelf-care, sleep, stress, anxiety and burnout in educational pages with WHO and NIMH sources
• BMI calculatorCalculate your BMI (weight ÷ height²) with the official WHO classification and the limitations everyone should know.
• Daily calorie calculatorCalculate your BMR and daily calories to maintain, lose or gain weight, using the Mifflin-St Jeor equation.
• Ideal weight calculatorCalculate your ideal weight as the range across the four classic formulas plus the healthy BMI range. Ideal weight is a reference, not a medical target, and the formulas diverge.
• Body fat percentage calculatorEstimate your body fat percentage with the US Navy method, using only a tape measure. See the formula, the reference categories and the margin of error versus DEXA.
• Daily water intake calculatorCalculate how much water to drink a day using the 35 ml per kilo rule, adjusted for exercise. It is a rule of thumb: real need varies with climate and health.
• Due date calculatorCalculate the due date with Naegele's rule (LMP plus 280 days) and see your weeks of pregnancy. It is an estimate: only about 5% of babies are born on the date.
• Ovulation calculatorEstimate your fertile days and ovulation day from your LMP and cycle length. It is an estimate, not a contraceptive method: cycles vary and ovulation can shift.
• Macro calculatorCalculate your macros in grams from target calories and goal (maintenance, cutting or bulking). These are starting points, not a nutrition prescription.