About Ancestor Assist

The calculators

Each calculator is built around a problem that recurs in family history rather than a general-purpose one, and each is described on its own page.

What they share is how they handle imprecision. The arithmetic runs against the real calendar — actual month lengths, the leap-year rule in force for the year in question — rather than the approximations that were convenient before computers. Where a date is only partly known, the answer is a range rather than a single guessed day, and the range narrows as the evidence does.

The forms

The forms are made to hold up as part of a research file. Census extraction sheets follow each year's own schedule column for column, so a transcription can be checked against the original without translating headings; the rest — family group sheets, pedigree charts, and the research worksheets — cover the recording and the reasoning around a record. Forms come two ways: a blank to print and fill in by hand, and a fillable version to type into in the browser and then print or save as PDF.

Sources

Reference material on this site — calendar adoption dates by country, census reference dates, the conventions of Old Style dating — is drawn from primary and standard secondary sources.

The site

Ancestor Assist is not affiliated with any other genealogy service, archive, or society. This website carries advertising; how that works, and what data the site does and does not collect, is set out in the privacy policy.

Corrections

Historical reference data is exactly the kind of thing that can be wrong in small ways. If a date, a conversion, or a form heading looks off, please say so — with the source, if there is one.