GAEB X81, X83, X84, X89 – which file is for what?

What do the codes X81, X83 and X84 mean?

The numbers denote phases in the data exchange, not file formats. Simplified: the X81 contains the tendered Leistungsverzeichnis, the X83 is the invitation to bid, and the X84 goes back to the client with your prices.

The X stands for the XML version of the exchange format (GAEB DA XML). Older files carry a D or P – in substance the digits mean the same thing.

The phases at a glance

The direction is the point to remember: X81 and X83 come in, X84 and X89 go out.

When do you get what?

X81 – description of works. The plain bill of quantities with item numbers, texts, quantities and units, without prices. Often for information or in a negotiated procurement.

X83 – invitation to bid. In practice the most common case in a tender. Structured like the X81, but explicitly as an invitation to submit a bid.

X84 – bid submission. Your answer. You enter the unit prices and send the file back. This is where the most common error happens: sending back the wrong phase.

X89 – invoice. Less widespread than X81/X83/X84, but encountered in civil engineering: the invoice based on the measured quantities. Not to be confused with the XRechnung – that is a different standard for a different purpose.

The most common error: returning the wrong phase

If you receive an X83 and send back an X83 with prices entered, the file is as a rule rejected. What is expected is an X84.

The reason is not formalism: the procurement office reads the incoming files by machine and compares bids. A file in the wrong phase does not fit that process.

Practical tip: Check two things before sending – the phase and the completeness. An X84 with no price in a mandatory item is just as worthless as the wrong phase.

X81 or X83 – do I have to be able to tell them apart?

For daily work: no. Software that handles the import recognises the phase from the file and outputs in the phase that is expected. You do not have to know the codes by heart.

For the conversation with the procurement office: yes. When somebody there says “send the 84 back”, you should know what is meant.

What is in the file – and what is not

That matters for expectations: a GAEB file does not replace the tender documents. It contains the calculable part, not the contractual one.

When the client only sends a PDF

It happens, particularly with smaller municipalities. Then the machine-readable basis is missing and the items have to be entered by hand – with everything that brings in the way of typos.

Ask for it. The GAEB file almost always exists; it simply is not sent automatically, because the PDF is meant for a human. A short email to the procurement office can save you half a day.

Why the item numbers have to be preserved

On import the temptation is strong to convert items into your own numbering. Do not. At the audit the number from the contract is what is asked for – not your internal one.

The same applies to the Aufmaß: a quantity has to hang on the item number the client knows. Anything else produces queries that cost weeks.

Frequently asked

What is the difference between D83 and X83? Only the file format. D stands for the older version, X for GAEB DA XML. The phase – and with it the meaning – is the same.

Can I open a GAEB file with Excel? Not usefully. It is a structured file, not a spreadsheet. You need a program that reads the format.

Do I need expensive software for the import? Not necessarily – there are simple viewers for a look inside. The benefit only arises once the items are used afterwards: pricing, measuring, billing.

Is X89 the same as XRechnung? No. X89 is a GAEB phase for the invoice based on take-off data. The XRechnung is a European standard to EN 16931 for the electronic invoice. Some clients require both – for different purposes.

We receive the file with the extension .p83. What is that? The P extension stands for the price phase in the older data exchange – in substance the invitation to bid. Treat it like an X83: price it and return it in the expected phase. If in doubt, ask the procurement office which format the return is expected in.

Can we send a priced bill of quantities back as Excel? Only if that is expressly permitted. In a formal procurement, returning in the required exchange format is as a rule part of the formal requirements – and a bid that misses the form is excluded, however good the price.

The tender documents are in German and our German is limited. Where do we start? With the GAEB file. Item number, quantity and unit sit there structured and need no language; only the long texts have to be understood. Which makes asking for the GAEB file instead of the PDF even more valuable for a firm with limited German than for one without: the readable part of the bill of quantities is language-free already.

What is structurally inside a GAEB file

Anyone who has looked inside once understands why items can be taken from it reliably – and why a PDF cannot do that.

The item type is often overlooked and expensive when it is: a contingency item is only billed if it is actually ordered. Costing it like a normal item distorts your bid price.

The hierarchy decides whether your billing later matches the client’s bill of quantities. Titles and sub-titles should be preserved even if nobody internally needs them.

When genuinely only a PDF arrives

It happens, above all with smaller municipalities and in negotiated procurement. The order to proceed in:

1. Ask. A short email to the procurement office: “Could you also make the bill of quantities available as a GAEB file (X83)?” In most cases it exists.
2. Ask the design office. If one is named in the documents, it almost certainly has the file – it was created there.
3. Only then enter it by hand. And then consistently with the client’s item numbers, not your own.

Steps 1 and 2 cost ten minutes. Step 3 for a bill of quantities with 140 items costs half a day – plus the typos that surface later during billing.

Typical import errors

The line about long texts matters in practice: without the long text the work is not fully described, and disputes about the scope arise later from exactly that.

What to check before sending

Before the X84 goes back, three checks that together take five minutes:

1. Phase correct? X84, not X83.
2. All mandatory items priced? An empty mandatory item can lead to exclusion.
3. Totals plausible? A typo in a unit price stands out in the final total once you look.

Those three points are the difference between a bid that is evaluated and one that is excluded – and they have nothing to do with software, only with discipline.

Contingency, alternative and optional items

These item types appear in almost every larger bill of quantities and are regularly mishandled when costing:

The contingency item is the most common error: it gets priced because it is in the bill of quantities, and then counted in your own total. That distorts the picture of the contract value – and if it is never called off, revenue you had counted on is missing at the end.

The surcharge is conversely often overlooked: not pricing it because it is “only” a surcharge means submitting an incomplete bid.

Software that takes these types from the GAEB file and shows them separately takes that bookkeeping off your hands. You should check it anyway – the classification comes from the client and is occasionally worth discussing.

In summary

What you really have to remember is one line: X81 and X83 come in, X84 goes back. The software handles the rest – provided it masters the phases and keeps the client’s item numbers.

How the import works at Levora is on the page about GAEB and bill-of-quantities import . What happens to the quantities afterwards is described in Take-off to REB 23.003 .