Developer Utilities
Small developer utilities that save a trip to a random website. Encode and decode Base64, explain a regex, build UTM links, generate QR codes and vCards, and more — the everyday helpers. Free in your browser, and available by API when you need them in a script.
Developer Utilities
Quarts to liters converter
US & imperial quarts, free
POST /cook/quarts-liters$0.002Developer Utilities
Recipe scaler
scale ingredient amounts by servings or multiplier, free
POST /cook/recipe-scale$0.002Developer Utilities
Rice cups to grams converter
raw or cooked, free
POST /cook/rice$0.002Developer Utilities
Sugar cups to grams converter
granulated, brown and powdered by density, free
POST /cook/sugar$0.002Developer Utilities
Tablespoons to ml converter
US, metric & Australian tbsp, free
POST /cook/tbsp-ml$0.002Developer Utilities
US to metric cooking converter
cups, tbsp, fl oz ↔ ml, g, free
POST /cook/us-metric$0.002Developer Utilities
Yeast conversion converter
active dry, instant & fresh, free
POST /cook/yeast$0.002Developer Utilities
Add days to a date
ISO calendar date plus or minus N days, free
POST /date/add-days$0.002Developer Utilities
Add years to a date
ISO calendar date plus or minus N years, free
POST /date/add-years$0.002Developer Utilities
Birth flower by month
traditional birth flowers for each month
POST /date/birth-flower$0.002Developer Utilities
Chinese zodiac element calculator
animal + five-element year in the 60-year cycle, free
POST /date/chinese-zodiac-element$0.002Developer Utilities
Countdown between two dates
days hours minutes seconds, free
POST /date/countdown-between$0.002Developer Utilities
Day of year to date converter
ordinal 1–366 to calendar YYYY-MM-DD, free
POST /date/date-from-dayofyear$0.002Developer Utilities
Day of the week calculator
name and number from an ISO date
POST /date/day-of-week$0.002Developer Utilities
Day of the year calculator
ISO date to ordinal day 1–366, free
POST /date/day-of-year$0.002Developer Utilities
Days in a month calculator
leap years included, free
POST /date/days-in-month$0.002Developer Utilities
Days left in the year
remaining days until December 31, free
POST /date/days-remaining-year$0.002Developer Utilities
Decade and century finder
year to 2020s & 21st, free
POST /date/decade-century$0.002Developer Utilities
Dominical letter calculator
Gregorian A–G (or two letters in leap years), free
POST /date/dominical-letter$0.002Developer Utilities
Doomsday rule calculator
Conway weekday from ISO date, free
POST /date/doomsday-weekday$0.002Developer Utilities
Orthodox Easter date calculator
Julian computus to Gregorian, free
POST /date/easter-orthodox$0.002Developer Utilities
Friday the 13th finder
every Friday the 13th in a year, free
POST /date/friday-13th$0.002Developer Utilities
Humanize duration
seconds to days, hours, minutes (readable)
POST /date/humanize-duration$0.002Developer Utilities
Leap year checker
Gregorian leap test and divisibility reason
POST /date/is-leap-year$0.002Developer Utilities
ISO weekday number
Monday=1 to Sunday=7 from an ISO date
POST /date/iso-weekday-number$0.002Developer Utilities
Julian Day Number calculator
ISO date to astronomical JDN, free
POST /date/julian-day-number$0.002Developer Utilities
Last weekday of the month
final Monday–Sunday date, free
POST /date/last-weekday-of-month$0.002Developer Utilities
Leap years in a range
count and list Gregorian leap years between two years, free
POST /date/leap-years-between$0.002Developer Utilities
Printable month calendar generator
weeks layout, free
POST /date/month-calendar$0.002Developer Utilities
Months between two dates
whole months and remaining days, free
POST /date/months-between$0.002Developer Utilities
Nth weekday of the month
third Monday, last Friday and any ordinal date, free
POST /date/nth-weekday-of-month$0.002Developer Utilities
ISO ordinal date converter
YYYY-MM-DD ↔ YYYY-DDD, free
POST /date/ordinal-date$0.002Developer Utilities
Previous weekday occurrence
most recent Monday–Sunday before a date, free
POST /date/previous-weekday$0.002Developer Utilities
Calendar quarter finder
ISO date to Q1–Q4 with start and end dates, free
POST /date/quarter-of-year$0.002Developer Utilities
Quarter start and end dates
Q1–Q4 calendar range, free
POST /date/quarter-start-end$0.002Developer Utilities
Recurring dates generator
every N days from start to end, free
POST /date/recurring-dates$0.002Developer Utilities
Season of the year calculator
meteorological season by hemisphere
POST /date/season$0.002Developer Utilities
US week number calculator
Sunday start, week 1 has Jan 1
POST /date/us-week-number$0.002Developer Utilities
Week start and end dates
ISO date plus first weekday to Monday–Sunday range, free
POST /date/week-start-end$0.002Developer Utilities
Weekday count in a year
how many Mondays, free
POST /date/weekday-frequency$0.002Developer Utilities
Weekend days between two dates
count Saturdays and Sundays in a date range, free
POST /date/weekend-count$0.002Developer Utilities
Weeks between two dates
whole weeks and leftover days from ISO dates, free
POST /date/weeks-between$0.002Developer Utilities
Year progress percentage
ISO date to % of calendar year elapsed, free
POST /date/year-progress$0.002Developer Utilities
Zeller's congruence calculator
weekday from ISO date, step by step
POST /date/zeller-weekday$0.002Developer Utilities
Zodiac element calculator
birth date to fire, earth, air, water
POST /date/zodiac-element$0.002Developer Utilities
Western zodiac sign calculator
birth date to sign, free
POST /date/zodiac-sign$0.002Developer Utilities
AWG ampacity calculator
max safe current by wire gauge
POST /elec/awg-ampacity$0.002Developer Utilities
AWG wire gauge calculator
diameter, area and ohms per metre, free
POST /elec/awg-wire$0.002Developer Utilities
Battery life calculator
runtime hours from mAh capacity and mA draw, free
POST /elec/battery-life$0.002Developer Utilities
Capacitive reactance calculator
Xc=1/(2πfC) in ohms, free
POST /elec/capacitive-reactance$0.002Developer Utilities
Capacitor charge calculator
Q=CV stored charge from C and V, free
POST /elec/capacitor-charge$0.002Developer Utilities
Capacitor charging calculator
V(t)=Vs(1−e^(−t/RC)) voltage during charge, free
POST /elec/capacitor-charge-time$0.002Developer Utilities
Parallel capacitance calculator
total C for capacitors in parallel
POST /elec/capacitors-parallel$0.002Developer Utilities
Series capacitance calculator
capacitors in series, free
POST /elec/capacitors-series$0.002Developer Utilities
Electric charge calculator
Q=It solve charge, current or time
POST /elec/charge-current-time$0.002Developer Utilities
Coulomb's law calculator
electrostatic force between two charges
POST /elec/coulombs-law$0.002Developer Utilities
Current divider calculator
branch currents for two parallel resistors, free
POST /elec/current-divider$0.002Developer Utilities
Electric field force calculator
F = qE, free in browser
POST /elec/electric-field-force$0.002Developer Utilities
Electric field calculator
E=kQ/r² point charge magnitude, free
POST /elec/electric-field-point$0.002Developer Utilities
Electricity cost calculator
appliance energy use and running cost
POST /elec/electrical-energy-cost$0.002