How to Convert 23andMe Raw Data to MyHeritage Format for Free

Go to healthosx.com/dna/convert, drop your 23andMe .txt or .zip, choose MyHeritage as the output, and download. The conversion runs in your browser, so the file is never uploaded and there is no account. Every genotype call is copied unchanged.

How do I convert my 23andMe raw data to MyHeritage format?

1. 1.Download a fresh copy of your 23andMe raw data if your current file has ever been opened in Excel or another spreadsheet.
2. 2.Open healthosx.com/dna/convert.
3. 3.Drop the .txt or .zip and choose MyHeritage as the format.
4. 4.Wait a few seconds and download the result.

A 23andMe v5 kit has roughly 630,000 markers. The conversion takes a few seconds in a modern browser, and the time depends on your device, not your internet connection, because the file is not uploaded.

What actually changes in the file?

The data does not change. The container does. 23andMe raw data is a tab-separated text file with comment lines beginning # and four data columns: rsid, chromosome, position, genotype. MyHeritage raw data uses comma-separated values with a header row and the column order RSID,CHROMOSOME,POSITION,RESULT. The converter reads the first layout and writes the second. The lactase SNP rs4988235 goes from the 23andMe-style rs4988235 2 136616754 AG to the MyHeritage-style rs4988235,2,136616754,AG.

The converter does not re-genotype your sample. It does not impute missing data, and it does not guess a genotype. If 23andMe wrote --, the output writes -- in the MyHeritage result field. Ordinary 23andMe chip files and MyHeritage chip files are both on GRCh37, so positions carry over unchanged. A GRCh38 input can be moved to GRCh37 on the same page, but that is a separate choice, not part of a plain 23andMe conversion.

Converting formats changes the container, not the contents. Your calls, no-calls, rsIDs and positions are copied; nothing is filled in.

Why not just rename the file or save it as CSV?

Because the extension is not the format. Opening a 23andMe file in Excel and choosing Save as CSV can change the separators, quote fields differently, and mangle -- no-calls. The converter writes MyHeritage's actual layout: comma-separated fields, the RSID,CHROMOSOME,POSITION,RESULT header, chromosome names such as 1, 2, X, Y, MT, and the -- no-call marker. The first line names the layout and says the file was converted, so nobody mistakes it for an original MyHeritage export.

Do I need this if I'm uploading to MyHeritage?

Probably not. MyHeritage has its own upload path for raw DNA files, and it often accepts 23andMe files directly. If your goal is to use MyHeritage itself, try the original 23andMe zip on their upload page first. This conversion is for the other case: another tool or pipeline says it requires a MyHeritage layout, or you need the RSID,CHROMOSOME,POSITION,RESULT columns.

If a service rejects the converted file, the common reason is the header line. The output does not pretend to be a download directly from MyHeritage. That is deliberate, but some automated screens only accept an exact company file and will refuse it.

What people get wrong

• Using an edited file. A 23andMe file that was opened and re-saved outside the original download may have broken separators. Start from the original download if possible.
• Expecting conversion to repair a bad file. If a 23andMe download stopped early, the converted file stops early too. The marker count will be lower, and conversion cannot recreate missing rows.
• Expecting no-calls to disappear. A no-call is a position the chip did not read. It stays -- in the output so downstream tools know it is missing instead of guessing.
• Expecting the file to upload anywhere. The page keeps your data local. It records that a conversion ran and its outcome, such as the formats used, never the file, its name or any genotype.

What to do after converting

Run the same raw file through the free report at healthosx.com/dna if you want the calls interpreted into readable trait, medication and ancestry results. Use the original 23andMe file or the freshly converted MyHeritage file, not a hand-edited copy.