Kitbench

Find the date N days (or N business days) after or before a date, with its weekday and Japanese era date (wareki). unit "business" skips Saturdays, Sundays and Japanese national holidays; "weekdays" skips only weekends. Good for deadlines in Japan. N from 0 to 100,000.

Calculate exact age from a birth date: age in years, years/months/days, Japanese kazoedoshi (traditional age), days since birth, next birthday and days until it, weekday of birth, Japanese era (wareki) of the birth date and the zodiac animal (eto). February 29 birthdays move to March 1 in non-leap years. Reference date defaults to today in Japan.

Calculate Japanese consumption tax with exact integer arithmetic: tax-excluded to tax-included or tax-included to tax-excluded, at 10% (standard), 8% (reduced) or any rate from 0 to 100 with up to 2 decimals, rounding down (floor, default), half up (round) or up (ceil). Returns the tax amount, both prices and the formula. Amounts are whole yen up to 13 digits.

Convert between Western (Gregorian) dates and Japanese era dates (wareki: Meiji, Taisho, Showa, Heisei, Reiwa), using exact era start dates and "gannen" (元年) for year 1. Give either date (YYYY-MM-DD), or wareki such as "令和元年5月1日" / "R1.5.1", or era + year + month + day. Rejects dates that do not exist in that era (e.g. Heisei 31-05-01). Range 1873-01-01 to 2200-12-31.

Convert units with official exact factors (NIST etc.), including Japanese units (tsubo, jo/tatami, shaku, sun, go, Japanese cups and spoons), temperature and fuel economy. Returns the exact result, a rounded display value, the factor, and extras such as feet-and-inches, inch fractions (1/16) and pounds-and-ounces. Unit ids by category - length: mm, cm, m, km, in, ft, yd, mi, nmi, shaku, sun; mass: mg, g, kg, t, oz, lb, st, ons, kwintal; temp: c, f, k; volume: ml, l, m3, tsp, tbsp, floz, cup, pt, qt, gal, flozuk, galuk, cupjp, tbspjp, tspjp, go; area: cm2, m2, ha, km2, sqin, sqft, sqyd, ac, sqmi, tsubo, jo, donum; speed: mps, kmh, mph, kn, fps; fuel: kml, l100, mpg, mpguk; pressure: pa, kpa, mpa, bar, psi, atm, mmhg; energy: j, kj, cal, kcal, wh, kwh, btu; power: w, kw, hp, ps; data: b, kb, mb, gb, tb, kib, mib, gib, tib.

Count characters in a text exactly as KitBench's character counter does. Counts user-perceived characters (grapheme clusters: emoji sequences, combining marks and flags count as 1), plus counts excluding newlines and whitespace, half-width characters counted as 0.5, lines, paragraphs, Japanese manuscript paper (genkō yōshi, 20x20) sheets, UTF-8 bytes, English words, and a breakdown into hiragana, katakana, kanji, Latin letters, digits and other. Strong for Japanese text and character limits. Text up to 200,000 characters.

Count the days between two dates: total days (optionally including the start day), weeks and days, years/months/days, Japanese business days (excluding weekends and Japanese national holidays from the Cabinet Office list) and weekdays (Mon-Fri). Exact calendar arithmetic, no time zones. Dates 1873-01-01 to 2200-12-31.