How to Open, Read, and Edit GAEB Files
Received a GAEB file and don't know how to open it? This guide shows you all your options — from free tools to professional AVA software.
Why Can't I Just Open GAEB Files?
GAEB files (.x81, .x82, .x83, .x84, .d81, .d83, .p83) use a specialized XML format designed for construction data exchange. Normal office programs like Word or Excel can't properly interpret these files. They contain structured bills of quantities with positions, quantities, units, and descriptions — information that only specialized software can display meaningfully.
Specialized XML Format
While technically XML, GAEB files follow the GAEB-DA-XML schema and require specialized parsers to read correctly.
Hierarchical Data
Bills of quantities are organized into titles, lots, sections, and positions — a plain text editor just shows raw code.
Calculation Logic
Quantities, unit prices, and totals are calculated automatically — this requires software that understands GAEB mathematics.
View GAEB Files for Free
For an initial overview, you don't necessarily need expensive software. There are several free ways to view the contents of a GAEB file — each with its own advantages and limitations.
Text Editor (Notepad++, VS Code)
Opens the raw XML data. You can see the structure but no formatted display. Useful for quickly checking if the file is complete.
Online GAEB Viewer
Web-based GAEB viewers allow you to upload and view GAEB files directly in your browser.
AVA Trial Versions
Many AVA software vendors offer free trial versions with full GAEB import — ideal for occasional use.
Professional AVA Software: What Matters
If you regularly work with GAEB files — for bid submissions or cost calculations — professional AVA software is worth the investment. These programs offer not just viewing, but editing, calculation, and export of GAEB files.
Full GAEB import and export
Import and export of all relevant GAEB versions (X81 to X86, D81/D83), so the priced BoQ goes back to the contracting authority without detours.
Costing at item level
Unit prices, markups and costing approaches are held at the item, with item totals and the overall bid sum calculated automatically.
Optional and alternative items
Correct handling of optional, alternative and contingency items — otherwise the bid sum will not add up.
Checks before submission
Completeness and plausibility checks on the priced bill of quantities before electronic submission.
Editing GAEB Files and Creating Bids
Simply opening a file is the first step. For actual work — entering unit prices, adding calculation data, creating bids — you need a complete GAEB workflow.
Import the BoQ (X81/X83)
Load the bill of quantities (X81) or the bid request (X83) into your AVA software. Check positions, quantities, and descriptions for completeness.
Enter Prices
Enter your unit prices per position. The software automatically calculates position totals and the overall bid amount.
Export X84
Export your bid submission as an X84 file. Check the file in an independent viewer before submission to verify correctness.
Run Validation
Use validation tools to ensure your file complies with the GAEB standard and contains no errors.
Tips for Working with GAEB Files
Based on our experience with hundreds of GAEB files, we recommend the following approach for smooth processing.
Always Create a Backup
Save the original GAEB file separately before you start editing.
Check Encoding
Make sure your software correctly handles UTF-8 encoding — umlauts and special characters are frequent error sources.
Note the GAEB Version
Check whether GAEB 90, GAEB 2000, or GAEB DA XML 3.2 is required. The versions are not always compatible.
Proofread Before Submission
Open the finished bid file (X84) in a different viewer or program to catch errors that your software might conceal.
Frequently Asked Questions
How can I open GAEB files (X81, X83, D83) for free?
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Three options: (1) An online GAEB viewer parses X81–X86 and D81/D83 in the browser with no install. (2) A text editor (Notepad++, VS Code) shows the raw XML — fine for inspection, not for work. (3) Free trial versions of professional AVA software open GAEB, but with feature limits. For a quick visual check, an online viewer is enough.
What's the difference between X81 and X83?
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X81 is the bill of quantities handover (positions with quantities, empty price fields). X83 is the bid request: the same unpriced BoQ, issued by the contracting authority to bidders for pricing; the priced return is submitted as X84. Both use the same GAEB-DA-XML 3.3 schema but represent different phases of the procurement lifecycle.
Which GAEB viewer is best in 2026?
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For read-only access: any online viewer with GAEB-DA-XML 3.3 support. For editing with quantities, optional items and alternatives: professional AVA software. For AI analysis of a tender: BlackSwanAI parses GAEB natively and extracts risks, open questions and a go/no-go recommendation.
Can I open a GAEB file in Excel?
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No. GAEB files are hierarchical XML — titles, lots, optional and alternative items — that Excel can't interpret. Excel just shows the raw XML as text. For tabular editing you need real AVA software or an Excel export from a GAEB viewer.
How do I open a D83 file?
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D83 is the bid request of the older GAEB 90 generation — line-based, not XML; the priced return is submitted as D84. It's read by many AVA programs and by specialised online viewers. If your software supports only X83, the issuing authority can usually deliver X83 instead — a short request is enough.
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