Genealogy Calculators

Julian Calendar and Heliocentric system of date calculations.How often in genealogy do you need to know the difference between two dates? Or the age of the person at death? Or calculate a birth date?

Do you wonder which day of the week was the wedding or birth? There is a reference to Easter 1879 and you need to know that date. And what about figuring out exactly when those calendar dates shifted and changed?

Do you often calculate the relationships between relatives or figure out how many times grand a specific grandparent is to another person?

These are the times when genealogy calculators save us. Let’s explore a few.

Date and Age Calculators

Ancestor Search - Estimating birth and death datesAs mentioned above, calculating dates in genealogy is a daily process. We need to estimate birth dates, death dates, marriage dates, migration dates, and so much more.

Most date calculators are on sites that feature other tools as well.

Ancestor Search offers a variety of date and age calculators:

Other date and age calculators include:

While not helpful for investigating the dead, GenealogySearch offers an Exact Age Finder to tell you precisely, down to the seconds, how old someone is based upon their birth date and birth time. It’s fun, especially for working with children.’s Date Duration Calendar is more helpful is estimating lengths of time.

The Census Day

1820 US Federal Census exampleA challenge that faces all genealogists is called “The Census Day,” the date that the census is mandated. As explained by genealogist William Dollarhide on GenealogyBlog, from 1790 to 1820, Census Day was the first Monday in August, the day when all the statistics for the census were collected – not the day the census taker arrived at a household to collect data on the residents there. The data was collected over weeks or months prior to that August Monday, thus any children born between when the census data was collected and that Monday would not be in the census. Makes sense, but this has confused family historians for a couple hundred years.

The Golden Egg Genealogist has a downloadable spreadsheet to help you narrow the dates in and around Census Day to help estimate the birth of children born within that gap.

Roman Numerals

Online Calculator for converting to and from Roman Numerals.Many legal documents and records include dates in Roman numerals, resembling a form of code if you aren’t familiar with the system.

The RapidTables Roman numerals date converter does more than convert years. It coverts dates in Roman numerals. For example, 9 Feb 1777 would be II.IX.MDCCLXXVII.

Julian to Gregorian Calendar

When working with ancestors back in the 1500-1700s, you have to deal with the switch from the Julian Calendar to the Gregorian Calendar, a calendar correction that lost 10 days to adjust the calendar and compensate the lack of a strict 365 days to a year. It’s actually 365.25 days. Every country switched in a different year spread out over 300 years, ranging from as early as 1582 for Belgium to Estonia in 1918 and all dates in between.

To understand how complicated this is, consider these examples.

As countries switched, the calendar dates were…confusing. By the Julian calendar, it would be 28 Jan 1752, but by the Gregorian, 8 Feb 1752. To make things even more complicated, 31 Dec 1749 would be followed by 1 Jan 1749. Yes, the same year. Don’t ask why, just go with it. And 24 Mar 1749 was 25 Mar 1750 as a new year was started on 25 March to “catch up” with the lost days with the Julian calendar. Yes, very confusing.

Let’s make it even more crazy making. Italy, home of Pope Gregory, made the switch in 1582. Greece made the switch to Gregorian calendar in 1916. So much for being nice neighbors.

In France, the then strongly Catholic country embraced the change in 1582, but the area of Alsace waited until 1648, and Strasbourg in 1682. Researching in those areas, you have to know when the switch happened to help convert the dates to something familiar.

The United States, England, and Canada made the switch official in 1752, so you will find many a record date transcribed in different ways to accommodate the oddball rearranging of the dates.

There are many other examples, but luckily, you don’t have to do much work other than to know when the country in which you are researching made the switch. The rest may be helped with one of the Julian to Gregorian calendar converters.

The Change from Julian to the Gregorian Calender by Ancestors Search tool is exceptionally helpful. For a good explanation, check out the FamilySearch Wiki’s article on the switch from Julian to Gregorian calendars. If you wish to understand how the calculations work for yourself, check out this quick guide on ho to calculate with the Gregorian calendar.

Why stress over this? Use technology. The Keisan Online Calculator for Julian and Gregorian Calendar Calculator is ideal. Enter a date and pick a calendar and hit Execute. It displays the date in Julian and Gregorian calendars, and displays a graph comparing the two dates.

Scroll down and you will find excellent examples people have added to explain how they’ve used the tool. One person used it to translate a Julian date from a Sumerian tablet in the 4th millennium BCE, and other was trying to work out the contemporary date for the assassination of William Rufus on 2 Aug 1100 CE.

While on the Keisan Online Calculator, check out the other calendars they offer including Hijri, Iranian, Hebrew, and Mayan calendars and converters and age, date duration, how many days, day of the week, week numbers, and other date calendars.

Screenshot_2021-02-08 Julian and Gregorian Calendar Calculator

Why should you care about all these calendars? When you are transcribing and recording the dates in your research, it helps to match apples with apples. Converting the dates to a consistent form as you analyze events throughout 1752 and 1753, it helps to have them literally be consistent.

Other Julian and Gregorian Calendar converters and calculators include:

Relationship Calculators

Stephen Morse One Step Genealogy Relationship CalculatorWho is related to whom is one of the challenges we face, but counting the steps between greats and cousins can be head cracking.

Stephen Morse offers a One Step Relationship Calculator that helps you trace the confusing tangle of family connections. Each time you click one of the 12 family choices in the box, it drills down through the relationships. For example, my father’s parent’s brother’s child would be my 1st cousin once removed (blood relative).

Ancestor Search’s Cousin Relationship Calculator displays a relationship chart based upon one person’s relationship to another of the same ancestor.

Abueling’s Genealogy Calculators includes a generation calculator. Place the birth year of an ancestor and the birth year of the next person, or yourself, and it offers a rough calculation of the number of generations between the two.’s Cousin Calculator can be used online or downloaded.

If you want to do some of this manually, check out the relationship charts on FamilySearch.

Stephen Morse One Step Ahnentalfel CalculatorStephen Morse’s Ahnentafel Numbers in One Step is a calculator tool that helps you automatically number your relationships according to the Ahnentafel numbering system which numbers you, the start of the tree, as number one, your father as number 2, and mother as 3. Your father’s father would then be 4, double the number of his son, and your father’s mother would be double plus 1, thus 5. Your mother’s father and mother would be 6 and 7, double your mother’s numbers, and so up up the tree. This system is commonly used when numbering in a direct simple ancestral tree as it doesn’t take into consideration siblings. It can be confusing the further the tree goes back. Most genealogy software programs calculate this automatically, but on the rare chance you are doing this manually, this calculator would help.

Luckily, most genealogy software does these relationship calculations for us. Trying to remember them in your head can bend the mind as you figure out the relationship of your grandmother’s mother’s sister’s granddaughter from her third marriage.

How Far is It?

An experienced genealogist knows that people traveled and lived together, often moving across the planet together. Working with FANs (Friends, Associates, and Neighbors) and clusters, we make new discoveries all the time.

A key process is identifying proximity. How far away did they live from each other? Maps help.

Google Maps tracing the journey and travel time.

Google Maps can help you to locate your ancestors and their FAN club easily. Take it a step further to estimate how long it would have taken them to move from location to location. Google Maps calculates the distance by travel time – based upon today’s transportation options and road conditions. Want to determine how long it would take in the 1700s or earlier? Switch the transportation to walking or bicycles for a better estimate. Just remember that the roads we have now might not be the same as the roads they had available to them then, though many highways were built over old roadways.

Indies Unlimited publishing blog describes in detail how long it would take to get from one place to the next for writers exploring new worlds and historical fiction based upon real-world estimates. These are good suggestions as our ancestors often traveled with luggage, supplies, weapons, and through various terrain. Also, one would need to take into consideration the health and age of the person traveling? Young? Old? Athletic? Traveling alone or with others?

Here are some estimates for travel times, based on averages:

  • Walking: 4 miles (6 km) per hour; about 20 miles (30 km) a day.
  • Horses: 30 miles (30-40 km) a day at an average pace.
  • Wagons: Depending on the terrain and weather, and amount of weight and number of horses, estimate 15 miles (20 km) a day, maybe more with two or more horses.
  • Trains: Average speed for trains about 1900 was 20-25 mph (32-40 kph) with few straight lines with no obstacles moving past 40 or 50 mph (64-80 kph).

Here are some distance calculators to experiment with:

Inflation Calculators

As you pour through probate record inventories, put taxes, property values, and income into perspective, it helps to use an inflation calculator that shows you how the value of money has changed, and what common objects like food and transportation would cost compared to today’s values.Westegg Inflation CalculatorWestEgg’s Inflation Calculator has you enter the amount of money, the initial and final year between 1800 and 2020, and it displays an estimate. It reported that in 1800, USD $100 would cost $1,543 in 2020.

The Ancestor Search Inflation Calculator is similar, but ads the percentage of change. It also covers only from 1913 to 2015. USD $100 in 1913 would be valued in 2015 at $2171 with an inflation ind3x of 22.7%, a percentage change of 2171.7%.

The Official Data inflation calculator by Ian Webster includes the UK, Canada, Australia, Europe, and other countries. While the initial year form goes back to year zero, the calculator only estimates inflation after 1750.

The Bank of England Inflation Calculator dates back to 1209. It estimates that 100 GBP in 1209 would be equivalent to 208,278 GBP at a 0.9% average inflation percentage a year, a conservative average.

I Am Kate Historical UK Inflation Calculator goes back to 1751 and has a great chart to show you inflation changes. Of note, in 1755, the inflation rate was -6%. In 1757, it was 21.8%, a dramatic shift in the economy. In 1970, it was 6.4%, but by 1975 it was 24%. A fascinating look at the financial struggles your ancestors may have faced even recently.

Measuring Worth is a free site that explores the issues of inflation and economics in more detail. It compares annualized growth rates, relative values in US, UK, Australia, and Spain monies, stock growth rates, and of the most interest to genealogists, purchasing power today in the US and UK over the centuries.

In US dollars, in 1799, $100 has a relative income worth of about $44,000 to $75,500, give or take based upon the level of skill of the worker from Unskilled Worker to Production Worker. Dig deeper by clicking the link to get more details and you would earn that $100 in 1799 would be work about $2,185 in 2020 dollars.

The Daily Meal isn’t a calculator but an article that explores what food a dollar could by you from 1937 to 2000, reminding us that penny candy used to cost a penny.

The US Bureau of Labor Statistics broke food prices down over the past 100 years, citing bread in 1913 costing about 5 or 6 cents, today USD $1.42 for the cheap stuff. The smallest price changes were found in flour and sugar. In 1913, flour was about 3 cents per pound we assume, and today, 52 cents. Sugar went from 6 cents to 68 cents. Compare that to coffee that went from 30 cents to almost $6.

There are many other inflation calculators out there. There used to be some wonderful online calculators that would list prices of food, homes, and other products and services in that time period compared to today’s money, but my favorites are no longer supported. If you find a good one that helps us compare the value of base money with what it would buy at that time, please share it with us.

Historical Wages and Costs

When you discover your ancestors made $10 a day or $50 a month, what does that mean in today’s dollars. Here are some charts and calculators to help you put those numbers into perspective.

GoBankingRates Minimum Wages from 1938 to 2020. These numbers are based upon state averages and the federal guidelines.

While not covering an extensive time range, BusinessInsider offers a look at the value of USD $100 in 1920 to 2015. Make Change offers similar information looking back at how far a dollar would go 100 years ago.

Timeline and Event Calculators

While not specifically a calculator, the process of retrieving data from a database based upon a date or date range is a cool tool to keep in your genealogy toolbox.

Irrelevant to the purpose of the site and used to just draw in visitors, Scope System’s AnyDay in History tool is worth bookmarking. Enter a month and day and it generates major events on that day throughout history. It features famous birth dates, deaths, military POWs missing in action, holidays, religious history and observances, and general historical notes, some famous, some infamous.

Scopes AnyDay for September 11On the day we chose, September 11, Henry Hudson landed on Manhattan Island in 1609. D.H. Lawrence was born in England on that day in 1885, as was designer Valentino in 1932. Nikita Khrushchev died of a heart attack in 1971, ad did Luis Alvarez, noted physicist and Nobel Prize winner in 1988. In 1789, Alexander Hamilton was appointed Secretary of the US Treasury, and the Boston Red Sox eat the Chicago Cubs in the 15th World Series in 1918. In 1927 on this date, Babe Ruth hit is 50th of 60 home runs in baseball.

Scopeys AnyDay Custom Peer List.OurTimeLine’s Peers and Contemporaries offers a similar perspective by highlighting those alive during the same time as your ancestors, at least those who left their mark of influence.

They also offer OurTimeLine timeline creation tool. Enter in significant dates for your ancestor and it highlights historical events during that time period, putting your ancestors into the context of history.

Timeline for James Acy Knapp.

I tested it with my ancestor, James Acey Knapp (1836-1877). During his childhood, Michigan entered the US Union in 1837, and a depression and panic with massive inflation hit the US and other parts of the world. The Opium war between China and the English would have been front page news through much of his early childhood, with China ceding Hong Kong to the English at age 6. The first telegraph line message went from Washington DC to New York when he was 8, and Texas entered the Union at age 9, followed the next year by Iowa. He grew up in Illinois and/or Wisconsin we believe, and Wisconsin joined the Union when he was 12.

The third cholera pandemic ranged across North America from age 16 to 23, and likely he lost friends and family. At the time he would have been more than eligible for war, the Apache war started when he was 25, the same year Lincoln became president, followed by the start of the Civil War. If he fought n the Civil War, and we’re still researching that, he would have been 27 during the Battle of Gettysburg.

The dMarie Time Capsule by Ancestor Search is a favorite. Enter the date and it displays a custom page that lists consumer prices from that year, Academy Award winners, newspaper headlines, the music they listened to, and other news to help put your ancestors in the context of their time. It covers the years from 1800 to 2005.

DMarie Time Capsule for April 20 1937

It’s a fun journey through the years which might help you see the relevance of current events within the lifetime of an ancestor.

Genealogy Calculator Collections

One of the biggest collection of genealogy calculators is Ancestor Search, home of that time line generator above. This is a first stop for many genealogists wrangling dates and numbers.

The Age Calculator calculates the difference between any two dates and offers the age in the process.

The Perpetual Calendar allows you to enter the month and the year from 0000 to 9999 to display a calendar for that month.

The Day of the Week Calculator displays the day of the week for the date entered.

Parallax View offers a wide range of measurement tools and calculators that may help genealogists including a date formatting tool, conversion for lengths and weights, counting the days between two dates, calculating dates and lengths of time, calculation of possible birth dates given a specific age, and analyzing the overlap between multiple date ranges.

The Calculator Family History uses names and places to tap into their database and display information associated with that information. Skip the “Search for your family members” and type in a surname in the “Family Origin” section. It displays a map, usually of North America, that shows you the most areas where that surname was found. Use the timeline button below the map to show the change over the years. Scroll down and see occupations, then potential records. It’s a sales tool for, but it’s a helpful general information tool.

Ethnicity Calculator from GEDSite calculates the cultural ethnicity of the person researched. Genetic ethnicity is the DNA research. This is the national origin, tribe, or cultural ethnicity, the “group” your ancestors claimed heritage and association. For instance, my grandfather claimed more of his Norwegian heritage than American even though he was several generations from their immigration from Norway. To use this form, enter in the cultural ethnicity of any person in the form and it will calculate an estimate of the percentage of cultural ethnicity. It’s a fascinating way to explore heritage.

Share Your Favorite Online Genealogy Calculators

Well, that is just the tip of the genealogy calculator examples that are out there. Now it is your turn to share some goodies with us. What have you found?