Genealogy Calculators
Practical online tools for dating records and determining relationships
The calculators are precise to the input they're given, and no further. Enter two full dates and the answer is one exact date. Enter a year where the day is unknown, and the answer is the full range of possibilities rather than a single date the record never supplied. A gravestone age becomes a twelve-month window; a census age becomes the two calendar years the birth could fall in. The range is the honest answer, and it narrows as the evidence does.
Three facts — birth, death, and age. Enter any two and get the third.
Cousin Relationship CalculatorEasily work out cousin relationships — first cousin once removed, second cousins, and more — with a full relationship chart.
Julian ↔ Gregorian Date ConverterConvert dates between the Julian and Gregorian calendars — ten to thirteen days apart, depending on the century. Adoption dates by country included.
Old Style ↔ New Style Date ConverterConvert Old Style (OS) dates to New Style (NS). Handles the March 25th legal new year in pre-1752 English records.
Roman Numeral ConverterConvert Roman numerals to Arabic numbers and back — for gravestones, old documents, and record dates.
Perpetual CalendarFind the day of the week for any date in history. Full month view for any year — useful for dating old records and events.
Census Age CalculatorTurn an age recorded in a census into the range of years the person was born.