As an interior designer, you often double as an accountant, creating and sending invoices to your clients. After all, without an invoice, you cannot get paid for all your hard work. When billing an interior design client, you must create an invoice that includes the time you spent consulting with the client, the time you spent working on the project and any materials you purchased. Listing these items individually and creating a single invoice cuts down on confusion and errors, and allows the client to review project costs with ease.

Decide on an hourly rate for your services. Having a set hourly rate will help you create an accurate invoice after completing the project.

Conduct an initial consultation with your client. Discuss the project with your client to get an idea of the time you'll need to invest and the materials you must buy. Inform your client of your hourly rate. Keep a record of how long the consultation takes.

Create a record for the hours that you work. Each day, write down the date, total hours worked and and the time of day you worked. Include time spent consulting with the client on the phone, as well as the time spent shopping for or purchasing materials. Include your travel time.

Create a record of any materials or supplies you purchase. Save all the receipts.

Keep records of any money you paid to third-party contractors. For example, you might hire a contractor to install drywall in the house. Save the invoice from the contractor.

Divide your final invoice into three sections. Add up your billable hours in the first section. Include a list of dates and times worked, as well as a total. Add up any materials or supplies purchased in the second section. Create an itemized list showing all materials and total. Add up the cost of hiring third-party contractors in the last section. Show the total paid to the contractors. Include a final total that combines billable hours, materials and contract work.

Attach the receipts from materials and supplies purchased, and invoices for third-party contractors, to the back of the invoice. Deliver the invoice to the client in person, by mail or by email. Retain copies of all paperwork.

Tip

Do not forget to bill for phone calls, meetings and other time spent working with the client during the project. These hours add up.