InvoiceGenerator
How to Invoice as an Architect or Engineer in Nigeria
Back to Resources

How to Invoice as an Architect or Engineer in Nigeria

Olivia S

How to Invoice as an Architect or Engineer in Nigeria

In the Architecture, Engineering, and Construction (AEC) sector in Nigeria, projects don't take days; they take months or years. You are dealing with volatile material costs, shifting client scopes, and massive capital layouts.

If you attempt to bill for a ₦50 Million structural engineering consultancy using a single, flat invoice at the end of the year, you will likely bankrupt your own firm due to cash flow suffocation.

Professionals in the AEC space must master Milestone Invoicing. Here is the standard framework for billing large-scale intellectual and design services in Nigeria.

The Percentage-Based Fee Structure

Unlike a vendor selling a laptop at a fixed price, Architects and Lead Engineers typically charge a Percentage of the Total Construction Cost (often guided by the scale of fees published by bodies like the ARCON or COREN).

If the estimated cost to build a luxury client's mansion is ₦200,000,000, and your professional architectural fee is 5%, your total fee is ₦10,000,000.

You do not ask for ₦10M on day one. You break the invoice down chronologically across the lifecycle of the project.

The 5-Stage Milestone Invoicing Guide

To maintain a healthy, continuous cash flow ensuring you can pay your draftsmen and structural analysts, structure your invoices against project phases:

Invoice 1: Inception & Mobilization (10% - 15%)

  • When to send it: Immediately upon signing the contract, before a single CAD line is drawn.
  • Line Item Description: "Mobilization Fee (15% of Professional Fee): Initial site visit, project brief formulation, and conceptual sketching for [Project Name]."

Invoice 2: Schematic Design (15% - 20%)

  • When to send it: Upon client approval of the preliminary massing and floor plans.
  • Line Item Description: "Phase 2: Delivery and Client Approval of Schematic Design and Preliminary Layouts."

Invoice 3: Design Development & Planning Approvals (20%)

  • When to send it: When the designs are finalized and submitted to the government (e.g., Lagos State Physical Planning Permit Authority - LASPPPA) for execution approval.
  • Line Item Description: "Phase 3: Final Design Development and Preparation of Statutory Approval Drawings."

Invoice 4: Construction/Working Drawings (30%)

  • When to send it: Upon handing over the highly detailed structural, mechanical, and electrical blueprints to the main contractor.
  • Line Item Description: "Phase 4: Production and Delivery of Exhaustive Comprehensive Working Drawings and Tender Documents."

Invoice 5: Construction Supervision (Remainder 20%)

  • When to send it: Billed progressively (e.g., monthly) during the actual physical construction of the building to cover your site visits and quality control.

Handling Reimbursable Expenses

Engineers and Architects constantly spend out-of-pocket money on behalf of the client for immediate project needs: paying for soil tests, printing massive A0 blueprints, or paying statutory government filing fees.

Do not hide these in your professional fee. Bill for them separately as "Reimbursable Expenses". If you spent ₦150,000 on site soil testing, list it as a distinct line item on your milestone invoice, and attach the receipt from the soil laboratory as an annexure to your invoice.

Taxes Deducted at Source

If your client is a corporate entity (e.g., a real estate development company), they will deduct 10% Withholding Tax (WHT) from your professional fees, because Architectural and Engineering consulting falls strictly under "Professional Services." Ensure your TIN is prominent on the invoice so they can remit the WHT in your name.

Systematizing Your Invoicing

Because you are raising 5 or 6 different invoices for the exact same project over a 12-month period, keeping track of what has been paid and what is outstanding is critical.

A unified billing engine like InvoiceGenerator.ng allows AEC professionals to create a master project quote, and then specifically raise highly detailed, sequentially numbered invoices for each distinct milestone. It provides the heavy corporate aesthetic that billionaires and large developers expect when authorizing multi-million Naira payments.