Free GEDCOM Validator: Check Your Family Tree File for Errors Online
Before you import a GEDCOM file into your main genealogy software - or share it with a relative, a one-name study, or an online tree platform - it pays to validate it. A single bad date, broken family link or character-encoding bug can corrupt the file's behaviour everywhere it lands. Most desktop programs accept invalid GEDCOM silently, which means problems propagate before anyone notices.
GEDminer's free GEDCOM validator runs every standard structural and logical check against a .ged or .gedcom file in your browser. It reports impossible vital dates, malformed records, broken parent-child references, duplicate INDI/FAM IDs, character-encoding corruption, missing required tags, and dozens of other issues that desktop tools quietly let through. The file never leaves your device.
Use it as a pre-flight check before any import, merge or share. The validator is free, requires no signup, and runs on standard GEDCOM 5.5, 5.5.1 and 7 files exported from any major program - Family Tree Maker, RootsMagic, MyHeritage, Ancestry, Family Historian, Gramps, Heredis, Reunion, Legacy and more.
How GEDminer solves it
You don't know if a GEDCOM file you received is structurally valid.
Full structural validation against the GEDCOM spec - record IDs, required tags, hierarchy, cross-references and encoding all checked in one pass.
Structural ValidatorImpossible dates buried in the file (deaths before births, future events).
Logical date validation flags every contradiction with the offending GEDCOM line and an explanation.
Date Consistency CheckerBroken family links - children without parents, marriages without spouses.
Reference integrity check verifies every INDI ↔ FAM cross-reference resolves to an existing record.
Reference IntegrityGarbled accented names from a wrong character encoding.
Multi-pass encoding decoder (UTF-8, Windows-1252, Mac Roman, Latin-1) recovers names automatically.
Encoding RecoveryDuplicate individuals from sloppy merges.
Phonetic + fuzzy match scoring surfaces likely duplicates with confidence scores.
Duplicate FinderUnsourced facts you want to flag before sharing.
Sourcing audit lists every fact without a citation, weighted by importance.
Sourcing AuditFrom the maintainer
Why this validator does not auto-fix anything
A surprising number of "validators" silently rewrite your file: re-encoding text, dropping unrecognised tags, normalising dates. That feels helpful until you realise the auto-rewrite is now part of your data lineage and a brand new source of error propagation.
GEDminer is deliberately read-only. It tells you the line, the rule, and why the rule exists. You then fix it in whichever program is your source of truth, re-export, and re-validate. Slower in the short term, far cleaner in the long term.
What a real GEDCOM validator checks
Most "validators" online only check that the file *parses*. That isn't validation - it's barely a syntax check. A real validator covers four layers:
- Syntax - line endings, level numbers, tag casing, character encoding.
- Structure - required tags present, record types valid, INDI/FAM/SOUR/OBJE references resolved.
- Logical consistency - vital dates that don't contradict each other, parent ages plausible, lifespans within human range.
- Best practice - fully-cited facts, consistent place-name format, no orphan records.
GEDminer runs all four layers and reports each finding with the exact line number and a one-sentence explanation of why it matters.
Why validate before importing or sharing
Once a bad file is imported into your main tree, the errors mix with your existing data and become exponentially harder to extract. Once shared with a cousin or uploaded to a collaborative platform, those errors propagate into other researchers' trees and start appearing as "consensus".
A five-minute pre-flight validation catches the worst issues before they spread. See our companion guide on [GEDCOM error propagation](/guides/gedcom-error-propagation) for why this matters more than most people realise.
Privacy: validation runs in your browser
The validator parses your file using a Web Worker on your own device. Your GEDCOM is not uploaded for analysis. Community comparison uses anonymous, aggregate Tree Health statistics contributed automatically when the analysis runs - four percentages, your individual and family counts, and a one-way tree fingerprint computed locally from hashed identity signals. No names, dates, places or GEDCOM records are sent.
What the validator won't fix
GEDminer is read-only. It tells you what is wrong, where, and why - but it does not modify your file. Make the fixes in your usual genealogy program (RootsMagic, Family Historian, Family Tree Maker, Gramps, MyHeritage, etc.), re-export the GEDCOM, and re-validate to confirm a clean run.
This is intentional. A tool that silently rewrites your file would itself become a source of error propagation.
Step-by-step guides
Walk-throughs covering every part of the workflow, from upload to cleanup.
How to Find and Fix GEDCOM Errors
A practical guide to detecting impossible dates, missing records, duplicate entries, and other data quality issues in your GEDCOM family tree file.
GEDCOM Error Propagation: How Bad Family Tree Data Spreads
One wrong date, duplicate person, or bad merge can spread through a GEDCOM file and corrupt hundreds of downstream facts. Learn how genealogy errors propagate - and how to audit your tree before importing or sharing.
How to Recover a Corrupted or Broken GEDCOM File
A GEDCOM that won’t load can feel catastrophic. Most "corrupted" files are actually salvageable with a few targeted fixes. Here is the diagnostic workflow.
Fix Garbled Names in GEDCOM Files: Character Encoding Guide
If accented characters, apostrophes, or non-Latin scripts look broken in your family tree, the problem is almost always character encoding. Here is how to diagnose and fix it.
Finding and Merging Duplicate Individuals
Find potential duplicate individuals in your tree using smart matching, compare their records side-by-side, and learn best practices for merging them.
Understanding Your Tree Health and Data Quality Score
Learn how GEDminer evaluates your tree's data quality, what the health score means, and practical steps to improve your tree's completeness and accuracy.
Frequently asked questions
What does a GEDCOM validator actually check?
A proper validator checks four layers: syntax (encoding, line format), structure (required tags, valid record types, resolved cross-references), logical consistency (dates that don't contradict, plausible ages and lifespans) and best practice (sourcing, place-name consistency, orphan records). Many "validators" only check the first layer.
Is GEDminer's validator really free?
Yes. The validator and all the analysis tools are free with no signup. You only need an account if you want to save trees to a managed cloud database (encrypted in transit and at rest, max 3 trees per account); the community Tree Health Score percentile needs no account.
Will my GEDCOM file be uploaded anywhere?
No. Parsing and validation happen entirely in your browser and your GEDCOM is not uploaded for analysis. Community comparison uses anonymous, aggregate Tree Health statistics contributed automatically when the analysis runs - four percentages, your individual and family counts, and a one-way tree fingerprint computed locally from hashed identity signals. No names, dates, places or GEDCOM records are sent. Saving a tree to an account is separate and only happens if you sign in and choose to save.
Which GEDCOM versions are supported?
GEDCOM 5.5, 5.5.1 and 7 are all supported. These cover essentially every export from major desktop and online genealogy programs over the past 25 years.
Can the validator fix the errors automatically?
No, by design. GEDminer is strictly read-only. It tells you what is wrong with the exact GEDCOM line so you can fix it in whichever program you normally use. A tool that silently rewrites your file would itself be a source of error propagation.
What about proprietary formats like .ftw, .ftm, .rmgc?
These are not GEDCOM - they are vendor backup formats. Open the file in its original program (Family Tree Maker, RootsMagic, etc.), export as GEDCOM, then validate the resulting .ged file.
How big a file can I validate?
GEDminer is designed and optimised for files up to 150 MB, which comfortably handles trees with 200,000+ individuals. Files above 150 MB and up to a 500 MB hard cap can still be loaded after an explicit acknowledgement, but performance there is untested and recommended only for the most powerful computers. Files above the 150 MB cap are not saved to the cloud to protect bandwidth — you can still export results to a spreadsheet.
Why are my non-English names showing as garbled characters?
That is a character-encoding problem in the source file, not a display problem. The validator detects this and the encoding-recovery tool will tell you the original encoding so you can re-export from your software with the correct setting.
Related tools
Free GEDCOM Analyzer: Inspect, Validate and Visualise Your Family Tree Online
Upload a .ged file and get instant analysis: errors, duplicates, missing dates, migration maps, census gaps and a data quality score.
Find and Fix Family Tree Errors Automatically
Detect impossible dates, duplicate ancestors, missing parents and broken relationships in your family tree in seconds. Free, browser-based GEDCOM error checker.
Family Tree Data Quality: Score, Audit and Improve Your Genealogy Research
A weighted Tree Health Score - 40% completeness, 30% sourcing, 30% consistency - plus an anonymous community percentile.
Clean Up Your Family Tree: Remove Duplicates, Fix Dates and Standardise Places
Tidy up an inherited or messy family tree: merge duplicates, standardise place names, fix encoding issues and surface missing facts. Free, browser-based.
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