We have written about thirty articles and tutorials on the wide variety of tools on GEDmatch.
This “how to use” guide gives you a simple overview and sequence for beginners to follow without being overwhelmed.
I’ll focus here on the free tools. We’ll look at the paid tier in a separate guide.
What Is GEDmatch And Why Use It?
GEDmatch is a website that provides a set of free and paid tools to analyze your DNA results from the major DNA testing companies.
GEDmatch doesn’t perform DNA testing itself. Instead, the site has uploads of DNA results from millions of customers from companies like 23andMe, Ancestry.com, MyHeritage, FamilyTreeDNA, and more.
Using GEDmatch to find relatives and build family trees
Most of us use GEDmatch to get access to more DNA relatives than where we originally tested.
Did you test with Ancestry.com? You will find plenty of DNA matches on GEDmatch that tested with 23andMe and other places. And of course, vice versa!
Some of those “new” cousin matches may have uploaded a family tree that gives you new branches to explore.
In my experience, GEDmatch accounts are more like to reply to contact than on Ancestry or 23andMe (yes, I’ve tested with both companies).
Using GEDmatch to explore your ancient origins and ethnicity
Your DNA testing company probably gives you an Ethnicity Estimate that attempts to predict your mix of ethnicities within a few generations.
GEDmatch has a suite of tools that attempt to estimate how your DNA represents thousands of years of population migration.
Are you more Western Hunter-Gatherer than Ancient South Eurasian? GEDmatch has a calculator for that – and many more questions you didn’t know you could ask!
However, the ethnicity/admixture calculators can be bewildering and misleading. We have articles that guide you through using these tools while recognizing their limits.
Reasons Not To Use GEDmatch (Personal Preferences)
I’ll quickly run through some aspects of GEDmatch that are a “no, thank you” for some people. I’ll give you links if you want to explore further.
Change in ownership
The GEDmatch website was originally created in 2010 by a hobby genealogist to help his own research. For nearly a decade, many users liked the fact that the site was run by a tiny company that charged an optional fee to keep the lights on.
GEDmatch was purchased in 2019 by a giant DNA technology provider in collaboration with a venture capital firm. You can read about this in more depth in our article on who owns GEDmatch. Some users left the site due to this change.
Is GEDmatch safe?
You may be aware that the GEDmatch website was hacked in July 2020. We have an article that goes in-depth into the GEDmatch security breach.
I’ll mention here that the hackers couldn’t access our encrypted DNA results. However, emails and other account details were compromised.
The main consequence was that GEDmatch beefed up its technical security. I was personally comfortable with continuing my membership. The new owners have deep pockets to pay for improvements.
It’s also worth remembering that GEDmatch provides commercial services to U.S. law enforcement. The security levels must be high for that relationship to continue.
Speaking of law enforcement, that brings me to the next concern.
Privacy and law enforcement
Unlike some other DNA sites, GEDmatch actively co-operates with law enforcement agencies by providing access to its DNA database without big legal hurdles.
If you’re not so enthusiastic about this, you can opt out of law enforcement access when you’re uploading your DNA results (and any time aftward). Our tutorial will show you exactly how.
How To Get Started On GEDmatch
This is how you get started on GEDmatch. The links are to illustrated guides (some also have a video walkthrough).
Step 1: Download your DNA results from your testing company
- How to download 23andMe DNA results
- How to download Ancestry DNA results
- How to download MyHeritage DNA results
Step 2: Register and upload your DNA to GEDmatch
Follow this tutorial on how to upload DNA to GEDmatch.
Watch out for the step to opt in or out of law enforcement access.
Step 3: Wait for the processing to finish
A lot of the tools and functionality won’t be immediately available when you upload your DNA. Give the website a few hours to finish processing your data.
How to remove your DNA from GEDmatch
Having second thoughts? You can take your DNA off the site at any time.
Simply follow these steps to remove your DNA from GEDmatch.
Now I want to give you the minimum amount of concepts and terminology to get going with the GEDmatch tools.
Finding your kit number
GEDmatch gives your DNA results a unique ID in its database. You will use that unique ID to run the tools and reports on your results.
We have a full article on GEDmatch kit numbers that explains things like the history of how these IDs have changed format. But you don’t need to know that to get started (it will be useful later).
For now, you just need to know how to find your kit number.
Segments, cMs, locations
If you’re coming from Ancestry.com, then you’re used to counting how many cMs you share with your DNA matches. 23andMe users are more familiar with the percentages.
GEDmatch is big on how many cMs (centimorgans) are in the segment(s) of DNA you share with your matches.
And GEDmatch gets even more detailed in the information it gives you. Some reports don’t just tell you how many cMs in how many segments. They show you the start and end positions on the exact chromosome pair that contains the shared DNA.
The clip below from one of my reports shows the segment on chromosome 16 that I share with a DNA relative. GEDmatch gives me the start and end position.
You may be wondering why this is so great? When you have several unknown relatives sharing DNA on the same area of the same chromosome pair, then you’re on track to investigating a common ancestor for this group.
But that’s a more advanced topic. Let’s stick to getting started without being overwhelmed. I have just one more piece of terminology. It’s the last data column in the picture above: SNPs.
SNPs and Overlap (don’t worry too much about this)
You’re going to find out that the GEDmatch site is very fond of acronyms. But they didn’t coin SNP, which is pronounced as “Snip”.
Most of human DNA is identical – that’s what makes us human. An SNP is a specific position on a chromosome that is known to vary across our species.
DNA testing companies target SNPs for analysis. The picture in the previous section is telling me how many SNPs are in the segment of DNA that I share with my match.
You usually don’t need to pay attention to SNPs. Focus instead on the number of shared centimorgans and segments.
However, this information becomes more important when GEDMatch is comparing DNA results from different test companies and different technologies.
Their challenge is that different companies test different collections of SNPs. That means they are testing applies with…slightly different apples!
Again, you usually don’t need to worry about inaccuracies due to differing SNPs.
However, if you’re researching more distant relatives i.e. low centimorgan matches, then you should pay more attention to what is known as “overlap” on GEDmatch. We have an article on Gedmatch overlap that will guide you through the details.
When you’re starting out, I suggest you focus on your higher CM matches. That way you don’t need to worry about this kind of detail.
So let’s crack on and start using GEDmatch.
How To Use GEDmatch To Research Relatives
The GEDmatch Home Page has a list of free and paid tools. I suggest that the first tool that you launch is the One-To-ManyReport.
This gives you a list of your DNA matches, ordered from the closest down.
There are two versions of the One-To-Many Report on the free tier.
I like to use the version launched from the Free Tools section on the right of the Home Page. Click on the top link in the list of tools to open the report.
For the first run, simply enter your kit number and keep all the defaults.
The picture below is a truncated version of my display. I’ve highlighted the GED/WikiTree column, as you may not be familiar with these terms.
My third match has uploaded a family tree in the form of a GEDCOM file. When you click on the blue “GED” link, you’ll get a pedigree display with names of dates of deceased ancestors in this person’s tree.
You may be wondering where to start with all these matches.
If you’re coming from one of the big consumer DNA websites, then you’re likely familiar with your top matches on the original site. One of the easiest ways to get up to speed with GEDmatch is to find a match that you’ve already looked at elsewhere.
When you scroll over to the right of the display, you’ll see the “Source” column which shows where the DNA came from.
There’s no guarantee that people use the same names on their GEDmatch and Ancestry accounts. But I’ll be surprised if you don’t recognize some of the top matches across the lists on both sites.
There are a lot of columns in this display, and I ignore most of them. You’ll find a detailed breakdown in our in-depth guide to the GEDmatch One-To-Many tool. There are plenty of tips on how to make the best use of it.
Once you’ve spotted an interesting match, the next step is to examine your relationship in more detail by running the One-To-One Autosomal Comparison.
When you’re already working with the One-To-Many report, you can jump straight to the One-To-One comparison by clicking on the “Largest” column in the Autosomal section. The number is actually a link.
One-To-One Autosomal Comparison Tool
Many filters can be set before you run the One-To-One report. But you can simply launch it with all the defaults.
If you haven’t seen a chromosome browser before, then this report will seem like a page full of colors. What you’re seeing is a visual representation of 22 of your 23 chromosome pairs laid out in horizontal bars.
Scroll down until you hit a chromosome pair with a data table. This, coupled with a section in blue, shows a segment of shared DNA between your and your DNA relative.
You may notice that the number of centimorgans in this report is different from what is shown by the One-To-Many tool. That may the case with other displays.
It’s important to know that the One-To-One Autosomal Comparison shows the most accurate data.
It’s possible that the other reports may show DNA matches with low centimorgans that are eliminated as genuine matches by the One-To-One tool. So you should always check matches with the One-To-One before making contact or doing any in-depth research.
We have a full article on using the GEDmatch One-To-One Comparison tool, that will give you lots more details on how it works
GEDmatch lets you view the DNA matches in common with any two kit numbers in their database. That’s a big difference with other sites where one of the kits must belong to you.
But when you’re starting out, you’ll most likely be interested in shared matches involving your own kit.
The name of the tool is a bit of a mouthful: “People who match both or 1 of 2 kits”.
We have an in-depth article on how to use this tool to view your shared matches.
3D Chromosome Browser
If you’re not familiar with chromosome browsers, our in-depth article on the GEDmatch 3D browser also gives you the concepts and background.
I must admit that I’m not a fan of the 3D visualization. I prefer the 2-D format in the One-To-One Autosomal Comparison. However, some people love the 3D version. It’s worth following our tutorial and giving it a whirl.
The big advantage of the 3D browser over the free 2D version is that you can compare from multiple kits (from three up to nine).
If you’re doing this, then you’re probably trying to triangulate a group of kits to identify a common ancestor. At this point, the browser in the paid tier may be more useful to your research.
Adding Your Family Tree To GEDmatch
It’s a pity that many GEDmatch users don’t upload a family tree to the website.
The One-To-Many tool has a column named “GED WikiTree” that has a link to the tree page for your DNA matches who have one.
You will make life easier for your DNA relatives if you add your tree to the site. It accepts trees in the form of GEDCOM files.
We have a step-by-step guide to adding a family tree to GEDmatch.
Ancestor projects are a way for groups of GEDmatch users to collaborate on specific areas of research.
The focus may be on a single surname, a geographic region, or an ethnic community. They are often organized through private Facebook groups.
Our guide to GEDmatch ancestor projects will show you how to find relevant projects and get the best use from them.
Admixture Calculators And Ancient Ethnicity Estimates
The admixture projects on GEDmatch are probably the biggest source of confusion to new users.
This is partly because they are so unlike the ethnicity estimates on the major consumer DNA testing sites. Another reason is that there are lots of different calculators and they may give you wildly different results.
We have an overview that looks at which GEDmatch calculator is best for you – which largely depends on your recent ethnic heritage.
Individual how-to guides
If you want to jump straight into a specific admixture project, then we have individual guides to each one:
- How to use the Dodecad calculators
- How to use the MDLP calculators
- How to use the Eurogenes calculators
- How to use the HarappaWorld calculator
- How to use the Ethiohelix calculators
- How to use the PuntDNAL calculators
- How to use the Gedrosia calculator
You may find yourself drowning in a sea of acronyms when reviewing your admixture results. Our guide to GEDmatch abbreviations will come in handy.
Ancient humans and archaic remains
23andMe gives you an estimate of how much Neanderthal is in your DNA.
But GEDmatch is the only mainstream site that lets you compare your DNA to samples from Neanderthal remains. And it’s not just Neanderthal samples, there’s an entire collection of different ancient samples gathered together in a single project.
Our article on using the Archaic DNA Matches tool will guide you through reviewing this collection of samples.
Aside from the collection, there are other interesting DNA samples in the GEDmatch database. For example, some archaic samples that were recovered in Northern Ireland are available. You can learn more in our article on ancient Irish DNA on GEDmatch.
Other Specialist Features
So far, we’ve covered the use of the major free tools on the GEDmatch platform. This section touches on the tools that are more niche.
One-To-One X-DNA Comparison
An earlier section described the One-To-One Autosomal DNA comparison tool. There is a similar tool that works on one of the sex chromosomes.
The One-To-One X-DNA Comparison is available from the Tools menu. Personally, I rarely make use of it.
It compares shared DNA between two kits on the X chromosome in the 23rd chromosome pair.
Are Your Parents Related?
Another highly specialist tool is rather evocatively named “Are Your Parents Related”? Unlike the other reports, this tool only works on one DNA kit.
Both parents contribute one chromosome to our chromosome pairs. This tool evaluates whether there is significant shared DNA across both sides.
To run this tool on your DNA results, simply enter your kit number.
It’s important to note that some shared DNA is not uncommon. It could simply be a first or second cousin marriage in an earlier generation. If you see high amounts, I suggest you consult a genetic genealogist for further interpretation.
I sometimes search the GEDmatch forums to get answers to technical questions. However, they’re not particularly active.
GEDmatch also has a company Facebook page which displays announcements. And there are other Facebook groups where GEDmatch users exchange tips and post questions.