How to Interpret DNA Test Results

Receiving your DNA test results can be exciting—and sometimes confusing. You may see an ethnicity estimate, hundreds or thousands of DNA matches, shared DNA amounts, centimorgans (cM), and predicted relationships. But how do you know which parts of your results are most useful for genealogy?

In this guide, you’ll learn how to interpret DNA test results step by step. We’ll explain ethnicity estimates, DNA matches, shared centimorgans, relationship predictions, shared matches, and how to combine genetic evidence with traditional genealogy research.

If you’re completely new to genetic genealogy, start with our beginner’s guide to genealogy research before diving deeper into your DNA results.

How to Interpret DNA Test Results: At a Glance

• Understand what your ethnicity estimate can—and cannot—tell you.
• Learn how to read your DNA match list.
• Understand shared DNA and centimorgans (cM).
• Use relationship predictions as possibilities rather than exact answers.
• Compare family trees, shared matches, and other evidence.
• Use DNA results together with traditional genealogy records.
• Avoid common mistakes when interpreting small matches and ethnicity percentages.

1. Understand Your Ethnicity Estimate

One of the first things you’ll probably look at after receiving your DNA test results is your ethnicity estimate. Depending on the testing company, this may also be called an ancestry composition or ethnicity estimate.

These estimates attempt to identify which reference populations your DNA is most similar to. You may see regions such as Scandinavia, the British Isles, Eastern Europe, West Africa, or other geographic areas.

How Ethnicity Estimates Work

DNA testing companies compare sections of your DNA with reference populations and use statistical methods to estimate which populations may have contributed to your genetic ancestry.

The important word is estimate. Your ethnicity results are not a literal percentage breakdown of every country where your ancestors lived.

Why Ethnicity Estimates Can Change

Your ethnicity estimate may change when a company updates its reference populations or improves its statistical methods. A result you see today may therefore look different from the result you received when you first tested.

• They are estimates: They should not be treated as precise genealogical proof.
• Reference populations matter: Results depend partly on the populations used for comparison.
• Nearby regions can overlap: Genetic populations do not always follow modern political borders.
• Small percentages need caution: A small regional estimate may be difficult to interpret on its own.
• Results can change: Testing companies periodically update their models and reference data.

Use ethnicity estimates as a research clue, not as proof of a particular ancestor. If a result suggests Scandinavian ancestry, for example, you can investigate Swedish, Norwegian, or Danish records—but your conclusion should ultimately be supported by genealogical evidence.

For more information about DNA matching and how DNA results can be used for genealogy, you can also review MyHeritage’s DNA Matching guide.

2. Learn How to Read Your DNA Match List

For genealogy, your DNA match list is often more useful than your ethnicity estimate. A DNA match is another person who shares enough DNA with you to suggest that you may have a biological relationship.

The exact information displayed depends on the DNA testing company, but a match may include:

• Shared DNA: The amount or percentage of DNA you share.
• Centimorgans (cM): A measurement used to describe the amount of shared DNA.
• Number of shared segments: The number of DNA segments you share.
• Largest segment: The length of your largest shared segment, where provided.
• Predicted relationship: A possible relationship based partly on the amount of shared DNA.
• Family tree: A tree may provide clues about your shared ancestors.
• Shared matches: Other people who match both you and your DNA match.

For example, MyHeritage provides DNA match information including shared DNA, shared segments, possible relationships, and family-tree information. This information can help you investigate how a genetic match may connect to your family tree.

For a more detailed introduction, see our guide to how DNA matching works.

3. Understand Shared DNA and Centimorgans (cM)

Centimorgans (cM) are commonly used to describe the amount of DNA you share with a genetic match. In general, closer biological relationships tend to share more DNA, but the amount can vary substantially between people with the same genealogical relationship.

That means a cM value should not be treated as a single answer to the question, “How are we related?” Instead, think of it as a way to narrow down a range of possible relationships.

Why the Same Relationship Can Share Different Amounts of DNA

DNA is inherited through recombination. Two people with the same type of genealogical relationship can therefore share different amounts of DNA.

The possible relationship becomes even broader as you move further back in your family tree. Some distant cousins may share detectable DNA, while others with the same genealogical relationship may share no detectable autosomal DNA.

What to Remember About cM

• More shared DNA usually suggests a closer relationship, but it does not identify the exact relationship by itself.
• One cM value can fit multiple relationships.
• Distant relationships have wider possibilities.
• Half relationships and pedigree collapse can affect how much DNA two relatives share.
• Small amounts of shared DNA require additional evidence before you draw a genealogical conclusion.

For a practical way to explore possible relationships from a shared cM value, try our DNA Relationship Probability Calculator.

You can also explore the Shared cM Project at DNA Painter, which allows you to enter a shared cM value and explore relationships that can fit that amount of DNA.

4. How to Evaluate a DNA Match

Finding a DNA match is only the beginning. The real genealogical question is: Who is this person, and which ancestor do we share?

Instead of looking at one piece of information in isolation, evaluate the match using several types of evidence.

Start With Your Stronger Matches

Closer matches are often easier to investigate because the possible relationship range is narrower and the shared family history may be more recent.

However, don’t automatically ignore distant matches. A smaller match can become extremely useful when you can place that person within a particular branch of your family tree.

Look at These Four Things

• Shared DNA: How much DNA do you share?
• Shared matches: Which other people do you both match?
• Family trees: Do the two trees contain overlapping surnames, places, or ancestors?
• DNA segments: Where available, do segment-level tools provide additional evidence?

Our guide to analyzing DNA matches goes further into match analysis, clustering, and shared-match strategies.

5. Use Shared Matches to Find the Right Family Branch

One of the most useful techniques in DNA genealogy is comparing shared matches.

Suppose you have a DNA match but don’t know how that person fits into your family tree. If you and that person also match several other people who are known relatives from your mother’s side, that group can provide an important clue about which side of your family the unknown match belongs to.

Look for Patterns

When you investigate a group of shared matches, look for recurring:

• Surnames
• Locations
• Ancestors
• Family-tree branches
• DNA clusters

One match rarely tells the whole story. Several matches pointing toward the same family line can provide much stronger evidence.

MyHeritage also provides filtering and sorting options for DNA Matches, including filters related to family trees and ancestral surnames.

6. Combine DNA Evidence With Traditional Genealogy

DNA testing works best when it is combined with traditional genealogy research. A DNA match can provide a clue, but historical records can help explain how two people are actually related.

A useful approach is to work in both directions:

• Genealogy to DNA: Use your documented family tree to determine which ancestors could explain a DNA match.
• DNA to genealogy: Use DNA matches and their family trees to investigate branches of your family that are unknown or incomplete.

Build Your Family Tree First

The more complete your family tree is, the easier it can become to place DNA matches. Even a tree containing several well-documented generations can provide useful context.

See our guide on how to build a family tree for practical advice on starting and expanding your research.

Use Historical Records to Verify DNA Theories

Once DNA points you toward a possible family connection, look for documentary evidence such as birth records, marriage records, census records, church records, immigration records, newspapers, or other historical sources.

You can also explore our traditional genealogy research methods for strategies that can help verify family relationships.

7. Use DNA Segments and Triangulation for Advanced Research

Once you are comfortable working with DNA matches and shared matches, you can move into more advanced techniques such as chromosome analysis and DNA triangulation.

DNA triangulation involves comparing multiple people who share overlapping DNA segments and investigating whether those shared segments can be connected to the same ancestral line.

This type of analysis can be particularly useful when you are trying to determine which branch of your family tree is responsible for a group of DNA matches.

For a step-by-step explanation, see our guide to DNA triangulation.

You can also explore our free DNA Chromosome Browser if you want to investigate chromosome-level information.

8. Common Mistakes When Interpreting DNA Results

DNA test results can provide powerful clues, but they are easy to overinterpret. Keep these common mistakes in mind:

• Treating ethnicity estimates as exact facts.
• Assuming the predicted relationship is guaranteed.
• Assuming that every DNA match has an identifiable recent common ancestor.
• Overinterpreting a small amount of shared DNA.
• Ignoring family-tree evidence.
• Assuming that matching surnames prove a relationship.
• Ignoring alternative explanations such as half relationships or pedigree collapse.
• Sharing personal or genetic information without considering privacy.

How Accurate Are DNA Test Results?

The answer depends on what part of your DNA results you are looking at.

A DNA test can provide useful evidence about biological relationships, but the interpretation of a relationship is not always unique. The same amount of shared DNA can be consistent with more than one genealogical relationship.

Ethnicity estimates are different again. They are statistical estimates based on reference populations and can change as testing companies update their methods and databases.

For genealogy, the strongest conclusions usually come from combining:

• Shared DNA
• DNA match patterns
• Family trees
• Historical records
• Geographic evidence
• DNA segment analysis where appropriate

How to Use DNA Results to Find Unknown Relatives

If you are researching an unknown parent, grandparent, biological family member, or another difficult branch of your family tree, DNA matches can become especially valuable.

A practical starting point is to identify your stronger matches, examine their family trees, and group shared matches into family clusters. From there, look for recurring surnames, locations, and ancestral couples.

Once you have a possible family line, use traditional genealogy records to work backward and determine where your family trees connect.

Our guide to DNA testing for adoptees provides additional information for people researching unknown biological family connections.

Frequently Asked Questions About DNA Test Results

What does my DNA ethnicity estimate mean?

Your ethnicity estimate is a statistical estimate of how closely parts of your DNA resemble reference populations. It can provide clues about your ancestry, but it should not be treated as a precise record of where every ancestor lived.

How do I read a DNA match list?

Start by looking at the amount of shared DNA, the predicted relationship, shared matches, and any available family-tree information. Then investigate which family branch could explain the connection.

What does cM mean in DNA testing?

cM stands for centimorgan. In genetic genealogy, it is commonly used to describe the amount of DNA shared between two people. A higher shared cM amount generally indicates a closer relationship, but one cM value can correspond to several possible relationships.

How much DNA do cousins share?

There is no single amount that applies to every cousin relationship. Inheritance is random, and the possible range becomes wider for more distant relationships. Use the Shared cM Project to explore possible relationships rather than assuming one exact answer.

What is a good amount of shared DNA for genealogy?

There is no universal cutoff that makes a match useful or useless. Larger matches are often easier to interpret, but smaller matches can also become valuable when they form a consistent cluster with other matches or can be connected to a documented family line.

Can DNA testing help me find unknown ancestors?

Yes. DNA matches can provide clues about biological relatives and family branches that are difficult to identify through records alone. The most reliable approach is to combine DNA evidence with family trees and traditional genealogy research.

Can my ethnicity estimate change?

Yes. Ethnicity estimates can change when a testing company updates its reference populations, databases, or statistical methods. A change does not necessarily mean that your DNA changed; it means the company’s interpretation of the data changed.

Should I trust my DNA match’s predicted relationship?

Use the predicted relationship as a starting point rather than a certainty. Shared DNA amounts can fit multiple relationships, so consider family trees, shared matches, ages, known relatives, and historical records before deciding how you are related.

Choosing a DNA Test for Genealogy

If you have not taken a DNA test yet, or you are considering testing with another company, look beyond the ethnicity estimate. For genealogy research, the size and usefulness of the DNA match database, family-tree integration, available tools, and ability to analyze matches can all matter.

For example, MyHeritage combines DNA matching with family-tree information and provides tools that can help users investigate DNA matches and potential family relationships.

Before choosing a test, compare the available options in our DNA test comparison.

You can also see our current guide to the best DNA tests for genealogy.

Next Steps: Start Working With Your DNA Matches

Now that you understand the basics of how to interpret DNA test results, start with the information that is most useful for genealogy: your DNA matches.

Review your stronger matches, examine shared DNA and relationship predictions, compare family trees, investigate shared matches, and use traditional records to test your theories.

As you become more experienced, you can move into advanced techniques such as DNA triangulation, chromosome analysis, clustering, and segment research.

Explore our complete collection of DNA and genealogy guides, or try our free genealogy and DNA tools to support your research.