What you get for a .SUM file
We don't have a dedicated viewer for this format, so we identify and inspect it instead — honestly, only what can be read from the file.
Drop your .SUM file
Choose it or drag it in. It's read right here in your browser.
We identify it
We read the magic bytes to tell what the file really is, its MIME type, and whether the name matches the contents.
See the details
Any metadata we can extract (dimensions, EXIF/GPS, document author and dates), a hex view, plus readable text and strings found inside.
What is a .SUM file?
Plain text that programs, servers and people write every day.
A .SUM file is a Garmin Checksum File used for data verification. It typically contains checksum information generated by Garmin devices or software to ensure data integrity. These files can be opened and processed by applications such as eSignal and Garmin Connect.
Programs that open .SUM files
| Full name | Garmin Checksum File |
|---|---|
| Developer | Garmin Ltd. |
| First released | early 2000s (alongside Garmin IMG map format) |
| Category | Text & Code |
| MIME type | application/octet-stream |
Related viewers
Every viewer is free to use.
Frequently asked questions
Is my .SUM file uploaded anywhere?
No. The file is read and highlighted for you.
Why do some characters look wrong (é, ł)?
That usually means the file was saved in one encoding and opened in another. We detect UTF-8, UTF-16 and the Windows-1250/1252 code pages automatically and show which one was used.
Can it handle huge log files?
Yes, up to 50 MB. Only the lines on screen are drawn, so scrolling stays smooth. Syntax colours are switched off for files over 1.5 MB to keep things fast.
How do the log level filters work?
We find levels like ERROR, WARN, INFO and DEBUG on each line. Lines without a level, such as stack traces, stay with the entry above them, so filtering to errors keeps the full trace.
Can I edit the file?
This is a viewer. To change code, download it or copy it into your editor. Converting encodings and line endings is planned.
Was this tool helpful?
Your rating helps us decide which tools to improve next.