The question 'What's the difference between GAEB X83 and X84?' is one of the most frequently asked in the German construction industry. And rightly so — because mixing them up can lead to your bid being rejected. This article explains the differences, correct usage, and most common mistakes.
GAEB Formats in Context: The Procurement Process
To understand X83 and X84, you need to know the procurement process. The GAEB standard maps the entire workflow into file formats: X81 contains the bill of quantities without prices — this is the tender the client sends out. X82 is the BOQ with price components for internal calculation purposes. X83 is the bid format — the bidder enters prices and submits this file. X84 is the contract award — the client confirms the award with this format. X86 contains measurement data for billing. Each format has a defined role in the process. X83 and X84 sit at the most critical point: the transition from bid to contract.
X83: The Bid Format
The X83 file is the electronic bid. It contains the bill of quantities with the bidder's unit prices, total prices, and any surcharges. When a contracting authority requires electronic bid submission through an e-procurement platform, they typically expect an X83 file. The file is machine-readable and allows the authority to automatically compare prices across all received bids. Technically, X83 is based on the GAEB DA XML 3.x standard — an XML schema that precisely defines the data structure.
X84: The Contract Format
The X84 file is created by the client after awarding the contract. It contains the bill of quantities with the contracted prices and marks the binding contract conclusion at the file level. The bidder doesn't create an X84 file — they receive it. In practice, the X84 is often used to import the contracted services into the company's own calculation or ERP system. This eliminates manual order entry.
The Most Common Mistakes in Practice
Mistake 1: Submitting X84 instead of X83. Happens more often than you'd think — especially when files get renamed. Contracting authorities reject incorrectly formatted submissions. Mistake 2: Creating X83 with the wrong GAEB version. If the tender is based on GAEB DA XML 3.3, the bid must also use this version. Version conflicts cause import errors. Mistake 3: Manually editing prices in the X83. GAEB files should not be edited with a text editor. The XML structure is sensitive — one wrong character can make the entire file unusable. Mistake 4: Modifying items in the X83. The client's bill of quantities is binding. Adding, deleting, or restructuring items leads to bid exclusion.
Older GAEB Formats: DA81, DA83, P83
Alongside the current XML formats (X81-X86), older GAEB versions still appear in practice. DA81 and DA83 are based on the older ASCII format (GAEB 90 / GAEB 2000). P83 is the predecessor format of the X83 file. Some contracting authorities and older AVA programs still use these formats. Modern software should handle both worlds — both the legacy DA formats and the current XML variants. When submitting bids: Always use the format specified by the contracting authority.
Analyzing GAEB Files Automatically
Regardless of format — whether X83, X84, DA83, or P83 — the real challenge isn't opening the file, but understanding its contents. Manually evaluating a bill of quantities with 500+ items takes hours. AI-powered analysis can accelerate the content evaluation: Which items are critical? Where are the risks? Are there missing items that are technically required? This works across formats — whether the BOQ comes as a GAEB file, PDF, or Word document.
Conclusion
X83 = Your bid to the client. X84 = The client's contract to you. Avoid mix-ups, ensure version consistency, no manual XML manipulation — those are the three most important rules when working with GAEB bid formats.