A DNA match tells you that you are related to someone, not how. In the Czech lands and Slovakia, the records that can show how are good, often digitized and detailed, so the work is to build both sides of the family down from a possible common ancestor and see where they meet. This guide gives a practical method and describes the traps that Czech and Slovak names, languages and borders set along the way. We checked these details in October 2026, and company features, database sizes and prices change often, so confirm them before you buy.
DNA is the lead, records are the proof
A shared amount of DNA, an estimated relationship and a computer-generated suggestion are all leads. A documented line of parish registers, censuses and civil records is proof. Treat every DNA-based idea as a hypothesis until each link is confirmed on paper.
Step 1: Estimate the relationship
Use the Shared cM Project tool at DNA Painter. Enter the amount you share, note which relationships have averages close to it and look at the histograms. The project is based on nearly 60,000 known relationships, and for distant relationships its averages include only people who shared DNA, with no adjustment for pedigree collapse or endogamy. A single number often fits several relationships, which is normal.
Step 2: Place the match on a side of your family
Check which of your relatives the match also matches. Testing first and second cousins and older relatives helps you sort matches by side, and clustering tools such as MyHeritage’s AutoClusters group matches who likely descend from common ancestors.
Step 3: Compare trees
Look at the match’s tree for shared surnames and villages, with Czech, Slovak, Hungarian and German forms in mind. On MyHeritage, our primary recommended platform, Theory of Family Relativity uses trees and records to suggest how you and a match might be related. Treat each suggestion as a hypothesis, and expect trees to contain errors. Note village names carefully, since a village has several names. See how to find the village of origin.
Step 4: Name the candidate common ancestors
From the relationship estimate, work out how far back the shared ancestors might be. Write down each candidate couple and the evidence for them, and note the parish and the house number if you have them.
Step 5: Prove each link in the registers
- Start from your own line. Follow your ancestors back through the parish registers. See our Czech parish registers guide and our Slovak records guide.
- Use the house number. Czech baptism records give the house number and district, which links a family across births, marriages and censuses. See our guide to censuses.
- Use the mother’s maiden name and her parents. Baptism entries often give them, which opens the next family.
- Build the match’s line the same way, from their known ancestors back toward the candidate couple.
- Identify siblings. A common ancestor should have children who lead to both of you.
- Look for the point where the two lines meet, and check that the shared cM is plausible for that relationship.
Step 6: Look for corroboration
Several matches who descend from the same couple, and who also match each other, strengthen the case. MyHeritage says its chromosome browser lets you compare up to seven matches at once, and FamilyTreeDNA and GEDmatch offer comparison tools. Do not rely on a single match.
Czech and Slovak traps
- Feminine surnames. Women appear under -ová or -á, so search both forms. See our guide to women’s surnames.
- Diacritics and spelling. The same name may appear with and without marks, and in Czech, Slovak, German or Hungarian form. See our spelling guide.
- Very common surnames. A name like Novák is shared by thousands of unrelated families, so use villages, house numbers and given names. See our guide to common surnames.
- Several registers. Each denomination kept its own books, so a family may appear in a different church’s register. See our Slovak guide.
- Languages. Registers may be in Latin, German, Hungarian, Czech or Slovak. See our reading guide.
- Moves and borders. Families crossed borders, and the village may have changed states. See our regions guide.
- Names changed abroad. A match’s tree may show an American spelling. See surnames changed in America.
Record your evidence
For each connection, note the relationship estimate, the matches involved, the records for each generation and any doubts. Keep negative evidence too, such as a record that rules out a candidate. Cite every record with its archive, parish, volume and page.
What DNA cannot prove
A DNA match shows a biological relationship, not a legal one. A DNA result is not among the evidence the Czech and Slovak embassy pages describe for citizenship, which depends on registration and documents. See the citizenship guide and the complete guide to Czech and Slovak citizenship by descent.
Illustrative composite (not a real family): A reader shares 66 cM with a match in Slovakia. The Shared cM tool suggests a third or fourth cousin. The match’s tree names a couple in a village in the same parish as the reader’s great-grandfather. The parish register shows the couple’s children, one of whom is the reader’s great-grandfather’s father, and a second baptism confirms the other line. The DNA amount fits the relationship the records show.
Common mistakes
- Accepting a suggestion as fact. Test each link in records.
- Skipping the siblings. They show whether the lines meet.
- Trusting a match’s tree without checking. Errors are common.
- Ignoring the house number. It links families across records.
- Forgetting women’s surnames. Search the feminine forms.
Continue with how to find Czech and Slovak cousins with DNA and the best DNA test for Czech and Slovak ancestry, and browse DNA & Tools. Sources include the Shared cM Project tool, DNA Painter’s notes on the tool and a FamilySearch handout on reading Czech parish registers.
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