AncestryDNA is the best overall DNA test for finding relatives, primarily because it has the largest database of any testing company. More people in the database means more potential matches. But the best test for you specifically depends on where your ancestors came from, what kind of relatives you’re looking for, and whether you’re willing to test with more than one company.
Why Database Size Matters Most
DNA matching is a numbers game. A test can only connect you with someone who has also tested with the same company (or uploaded their data to the same platform). AncestryDNA has the largest overall database, which gives you the highest statistical chance of finding a match for any given relative. 23andMe has the second-largest pool of testers. MyHeritage and FamilyTreeDNA have smaller databases but serve specific populations that the bigger companies don’t cover as well.
If you only plan to take one test, AncestryDNA is the safest bet for sheer volume of potential cousin matches. But testing with a single company will always leave gaps, because your relatives may have tested somewhere else entirely.
Which Test Type Finds Which Relatives
All major consumer DNA tests use autosomal DNA testing, which looks at the DNA you inherited from both parents. This is the test designed to find living relatives on any branch of your family tree within about the last five generations, roughly your third cousins or closer. Beyond that range, shared DNA segments become small enough that matches grow unreliable.
Two other test types exist but serve narrower purposes. Y-DNA testing traces the direct paternal line (father to father to father) and is only available to people with a Y chromosome. It can confirm whether two men share a common male ancestor and reveal migration patterns going back thousands of years. Mitochondrial DNA (mtDNA) testing traces the direct maternal line (mother to mother to mother). Both sons and daughters carry mtDNA, but only genetic females pass it on. These lineage tests are useful for confirming a specific ancestral line, but they won’t help you build a broad list of cousins. FamilyTreeDNA is the only major company offering all three test types.
How Each Company Helps You Identify Connections
Getting a list of DNA matches is just the first step. The real work is figuring out how those matches fit into your family. This is where company tools differ significantly.
AncestryDNA’s biggest advantage beyond database size is its ThruLines tool. When you link your DNA results to a family tree on Ancestry.com, the system compares your tree against the trees of your matches. If it finds a person who appears in both, it flags the connection as a shared ancestor hint. You can click on any ancestor and review every DNA match who also has that person in their tree. This also activates shared surname and shared location features that help narrow down how you’re related to someone. ThruLines essentially does detective work that would otherwise take hours of manual research.
23andMe offers a DNA Relatives feature that shows your match list and estimated relationships, but it doesn’t have the same depth of family tree integration. 23andMe’s strength has traditionally been health reports bundled alongside ancestry, so if relative-finding is your primary goal, its tools are less developed than Ancestry’s. MyHeritage offers its own family tree matching system and has a large existing user base of genealogists who built trees on the platform before DNA testing was available, which can be helpful for connecting the dots.
Best Options for Non-U.S. Ancestry
If your family roots are outside the United States, the biggest database isn’t always the most useful one. MyHeritage has strong representation of testers from the Middle East and Scandinavia. Even with fewer total testers than AncestryDNA or 23andMe, it may have exactly the population crucial to your research if your ancestors came from those regions.
Living DNA is the only UK-based testing company and may surface matches for British Isles genealogy that don’t appear anywhere else. FamilyTreeDNA, with its multiple test types and long-standing presence in the genealogy community, attracts a different cross-section of testers than the bigger consumer brands. The practical takeaway: if you have ancestors from a specific region, check which company has the strongest presence there rather than defaulting to the largest overall database.
Cross-Platform Matching With GEDmatch
You don’t have to pick just one company. GEDmatch is a free third-party platform that lets you upload raw DNA data from 23andMe, AncestryDNA, FamilyTreeDNA, MyHeritage, Living DNA, and several other providers. Once uploaded, your DNA is compared against everyone else in GEDmatch’s database regardless of where they originally tested. This is the only way to match across company lines without buying multiple kits.
GEDmatch is particularly popular among serious genealogists, adoptees searching for biological family, and anyone who has already tested with one company and wants to cast a wider net without paying for another kit. The trade-off is that its tools are less polished than what you get from AncestryDNA or 23andMe, and the database is smaller since it only includes people who actively chose to upload.
What the Numbers Actually Tell You
DNA matches are measured in centimorgans (cM), a unit that reflects how much DNA you share with another person. The more centimorgans you share, the closer the relationship. A parent-child pair shares around 3,400 cM. But the tricky part is that a single cM range can correspond to multiple possible relationships. A match in the 575 to 1,330 cM range, for instance, could be a first cousin, a half aunt or uncle, or even a grandparent. Context from family trees and known family history is what turns a raw number into an identified relationship.
This ambiguity is one reason tree-linking tools like ThruLines are so valuable. Without a tree to cross-reference, you might know that someone shares 800 cM with you but have no way to determine which of several possible relationships is the correct one.
Accuracy Challenges for Some Populations
If your ancestry includes communities that historically married within a defined cultural, ethnic, or religious group, your DNA results may look different than expected. This practice, called endogamy, increases background DNA sharing across the entire community. Two people from an endogamous population might share enough DNA to look like second or third cousins when they’re actually much more distantly related.
Most relationship-prediction algorithms were trained on European-descent families in urban locations, so they tend to perform poorly for endogamous populations. This affects Ashkenazi Jewish communities, some Polynesian populations, founder populations like French Canadians in Quebec, and many others. Researchers have developed improved methods that can accurately identify first through fourth-degree relationships in endogamous groups, but these advances haven’t fully reached consumer platforms yet. If this applies to your background, expect to see inflated match counts and relationship estimates that skew closer than reality.
Cost Comparison
Basic autosomal testing from most companies falls in the $80 to $100 range at full price, though sales frequently bring kits down to $39 to $60. All companies charge an additional $7 to $12 for shipping to cover prepaid return mailers. AncestryDNA’s kit starts around $100 at regular price. FamilyTreeDNA’s basic autosomal test runs about $80, but if you add the company’s high-resolution Y-DNA and mtDNA tests, the total can climb past $360. FamilyTreeDNA’s à la carte pricing structure means costs add up quickly if you want comprehensive testing.
AncestryDNA also offers a separate subscription for full access to its genealogical records (census data, immigration records, historical documents), which is helpful for building the family tree that powers ThruLines. The DNA match list itself doesn’t require a subscription, but the tree-building resources that make those matches most useful do carry an ongoing cost.
Privacy Considerations
Uploading your DNA to any database means your genetic information exists on a company’s servers. 23andMe has required law enforcement to obtain a search warrant or valid legal process before accessing user data. However, 23andMe’s recent bankruptcy proceedings have raised questions about whether its previous privacy commitments will survive a change in ownership. Minnesota has enacted a law requiring genetic testing companies to obtain consumer consent before disclosing information to law enforcement without a warrant or court order, but most states have no comparable protection.
Every major testing platform lets you control visibility settings and delete your data. If you’re concerned about privacy but still want to find relatives, review each company’s current data-sharing policies before testing, and consider that policies can change when companies are sold or restructured.