hoai rechner

What Is a HOAI Rechner?

A HOAI Rechner is a practical calculator for estimating architectural or engineering fees based on the German fee framework (HOAI: Honorarordnung für Architekten und Ingenieure). In real projects, final compensation depends on contract terms, project type, scope, and legal updates. But a calculator helps you answer one immediate question:

“Are we in the right budget range before we start detailed negotiations?”

Why This Estimate Helps

• Owners and developers can plan realistic design budgets early.
• Architects and engineers can create faster first-pass proposals.
• Project managers can compare scenarios across project sizes and scope splits.

How This Calculator Works

This page uses a simplified model with five core inputs:

• Anrechenbare Kosten (chargeable project costs)
• Honorarzone (complexity level I–V)
• Rate position between minimum and maximum fee (0–100%)
• Selected Leistungsphasen (LPh 1–9)
• Nebenkosten + VAT for gross budget visibility

Behind the scenes, the tool builds a fee corridor (minimum/maximum), interpolates your selected rate position, applies zone weighting, and then adjusts for the selected LPh share.

Important Note

This is intentionally a quick estimator. It does not replace legal interpretation, official tables, project-specific agreements, or professional advice. Use it for orientation and planning conversations.

Step-by-Step: Using the HOAI Rechner

1) Enter chargeable costs

Start with a realistic cost basis. If your number is too optimistic, every later fee estimate will be too low.

2) Choose the correct Honorarzone

The zone reflects project complexity. Higher complexity generally means higher professional effort and fee levels.

3) Set your fee position

If you pick 0%, the estimate sits near minimum; 100% sits near maximum; 50% is the mid-range orientation.

4) Select Leistungsphasen

If the contract includes only early planning, check only relevant LPh. If full service is planned, keep all phases active.

5) Add expenses and VAT

Nebenkosten and VAT often get forgotten in early budgeting. Including both gives a better “decision-ready” total.

Example Scenario

Suppose you enter:

• Anrechenbare Kosten: €500,000
• Zone III
• Midpoint fee position (50%)
• All LPh selected
• Nebenkosten 3% + VAT 19%

You will receive a clear estimate of net fee, expenses, subtotal, VAT, and total gross amount. Then you can quickly test alternatives, such as excluding LPh 8/9 or moving to a higher complexity zone.

Common Mistakes to Avoid

• Ignoring scope boundaries: unclear LPh splits create pricing disputes later.
• Using outdated cost assumptions: even small cost shifts significantly affect fees.
• Forgetting VAT in board-level budgets: net and gross are not interchangeable.
• Treating estimates as fixed offers: a calculator is a planning tool, not a signed contract.

Final Thoughts

A good HOAI estimate is less about “perfect precision” and more about transparent decision-making. If everyone can see the same assumptions—costs, zone, fee range, and phases—budget conversations get faster and more objective.

Use this HOAI Rechner to prepare your first pass, then refine with project-specific documentation and professional review.