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Chapter VII

Calculators for family historians

Free, private, and they work on your phone. Nothing you type leaves your browser.

Form 1 · Census

Birth year from a census age

Census ages count from the official census day (for example June 1, 1850), not the day the census taker knocked.

Form 2 · Gravestone

Birth date from "aged 64 y. 3 m. 12 d."

Subtracts years, then months, then days, the way stone carvers counted.

Date of death
theday of,
Age on the stone
agedyears,months,days
Form 3 · Index

Soundex code

The 1880 to 1930 census indexes file names by sound. Spellings with the same code sit together.

Form 4 · Family

Cousin calculator

Count generations down from the shared ancestor: 1 for a child, 2 for a grandchild, 3 for a great-grandchild.

Form 5 · Calendar

Old Style to New Style

For dates written in the British colonies before September 1752, when the year began on March 25 and the calendar ran 10 or 11 days behind.

Date as written (Old Style)
theday of,
Form 6 · Calendar

What day of the week was it?

Handy for checking a record that says "died Sunday last" or "married on the Lord's Day". Uses today's calendar.

Date
theday of,