What an ATTLOG file is, and how to open or convert it

You export the attendance data from your fingerprint clock, open the file, and find a wall of numbers. No names, no columns, no dates you can read at a glance. Just rows like 1<TAB>2026-06-30 08:02:14<TAB>0<TAB>1<TAB>0. That is an ATTLOG file. It is more useful than it looks.

This article explains what an ATTLOG file contains, why it opens as an unreadable block, and the two ways to make it usable.

What an ATTLOG file is

ATTLOG is short for “attendance log”. It is the raw record a biometric attendance device writes every time someone clocks in or out. Most fingerprint and face-recognition clocks used by SMEs export it, including the widely deployed ZKTeco range. You get the file when you pull data off the device to a USB stick.

The file is plain text. Each line is one clocking event. Tab characters separate the values on that line, not commas. There are no column headings either. That is the first reason it looks so unhelpful when you double-click it.

What is actually inside each line

A typical ATTLOG line holds five pieces of information in a fixed order:

1. User ID — the number the device assigns to an employee, not their name.
2. Timestamp — the date and time of the clocking, usually as YYYY-MM-DD HH:MM:SS.
3. Status — a code for the type of clocking: in, out, break, or overtime.
4. Verify mode — how the person identified themselves: fingerprint, card, face, or password.
5. Work code — an optional field some businesses use to tag the reason for a clocking.

The status and verify columns are where most people get stuck, because they are stored as numbers. On most ZKTeco devices the status codes run 0 and 1 for check-in and check-out, 2 and 3 for break out and break in, then 4 and 5 for overtime. Verify mode commonly uses 1 for fingerprint, 2 for card, and 15 for face. These conventions vary between models. Check the codes against your own device manual before you rely on them for payroll.

The employee names are the other missing piece. The device stores names against user IDs internally, but the ATTLOG export gives you the IDs only. To make the file readable you need to map each ID back to a person.

Why it opens as gibberish

Double-clicking an ATTLOG file usually opens it in a plain text editor. That editor shows every tab and every raw code exactly as stored. Nothing formats it, nothing labels it, and nothing translates the status numbers into words. The information is all there. The presentation is the problem.

Two ways to make it readable

The manual route. Rename the file so it ends in .txt, open Excel, and import it as a tab-delimited file. Excel then splits the values into columns. This works, but it leaves you with the raw ID numbers and the raw status codes, so you still have to label the columns, translate the codes by hand, and match every ID to an employee. Do this once and it is a mild nuisance. Do it every payroll run and the minutes add up.

The quick route. We built a free ATTLOG converter that does the whole job in your browser. It reads the file, splits the columns, translates the status and verify codes into plain English, lets you sort the result, and exports it to CSV or Excel. The file never leaves your computer, because the conversion happens entirely in the browser rather than on a server, so nothing is uploaded anywhere. You can convert an ATTLOG file to Excel here.

When the export itself is the real cost

Reading one file is a small task. The problem is rarely one file.

Picture the monthly ritual. Someone visits the device with a USB stick. Every payroll run then starts with an export, a rename, an import, and a round of manual code translation. The cost is not the reading. It is the repetition, and the chance of a transcription error slipping into someone’s pay.

That is the point where a converter stops being enough and connected attendance starts to pay for itself. bitKode Attendance reads the same clock data automatically and feeds it into payroll. No export, no spreadsheet, no manual code lookup. The free tool solves today’s file. Connected attendance solves the cause.

For now, if you just need to read the file in front of you, the converter is here and free to use.