Interior design invoicing is uniquely complex. Designers bill for design fees, markup on product, hourly consultation, project management, install supervision, and reimbursable expenses, often within the same client engagement. A clear, professional invoice that separates these revenue streams is essential for client trust and for tax compliance. This guide gives you a free interior design invoice template along with billing models, markup conventions, and project management language that work in the US design market.
Designers bill multiple revenue streams in parallel. The invoice needs to show each clearly.
Every interior design invoice should include the following.
Product billing has its own conventions. Designers typically use one of three models: retail markup (sell product at retail and keep the difference between trade and retail price), cost-plus (charge cost plus a fixed percentage), or design fee + at-cost (charge a separate design fee and pass product through at cost). Each is fair and legitimate; the contract should state which applies.
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Use these as your baseline. Adjust for credential level, project scope, region, and specialization.
Hourly consultation rate:
Flat design fee (residential):
E-design (virtual, no install):
Project management fee: 8 to 15 percent of construction/install budget for large projects
Installation day fees: $135 to $475 per hour for on-site styling and supervision
Product markup models:
Reimbursable expenses (passed through at cost or with small markup):
Common fee structures:
Typical project budgets (FF&E and design fees combined):
Common phase billing:
Regional: New York, LA, Bay Area, Miami, and Chicago command 50 to 100 percent premium over national average. Trade-only resources (D&D Building NYC, Pacific Design Center LA) require designer license to access.
Here is an invoice covering a mid-project billing period including design hours, product purchases, and reimbursables.
Invoice INV-2026-0184
Date: 04/30/2026
Designer: Allison Chen, NCIDQ #142988
Studio: Allison Chen Design
Address: 1820 Beverly Drive Suite 4, Los Angeles, CA 90212
Client: Robert and Karen Martinez
Project: Martinez Residence, Bel Air
Reference Contract: AC-2026-014 (signed 02/15/2026)
Service Period: April 1 - April 30, 2026
Section 1: Design Hours
| Date | Description | Hours | Rate | Total |
|---|---|---|---|---|
| 04/03 | Living room concept revisions | 4.5 | $185 | $833 |
| 04/08 | Dining room schematic + 3D rendering | 6.0 | $185 | $1,110 |
| 04/15 | Kitchen elevation drawings | 5.5 | $185 | $1,018 |
| 04/22 | Material specification and procurement | 4.0 | $185 | $740 |
| 04/29 | Client presentation prep + meeting | 3.5 | $185 | $648 |
| Subtotal design hours | | 23.5 | | $4,349 |
Section 2: Product Purchases (Cost-Plus 25 percent)
| Description | Vendor | Cost | Markup | Total |
|---|---|---|---|---|
| Custom sectional sofa | Holly Hunt | $8,500 | $2,125 | $10,625 |
| Vintage Italian coffee table | 1stDibs | $4,200 | $1,050 | $5,250 |
| 8x10 hand-knotted rug | Loloi | $3,800 | $950 | $4,750 |
| Pair of side tables | RH Modern | $1,950 | $488 | $2,438 |
| Subtotal product | | $18,450 | $4,613 | $23,063 |
Section 3: Reimbursable Expenses (at cost)
| Description | Total |
|---|---|
| Sample tiles and fabric (10 vendor visits) | $185 |
| Presentation prints, large format | $94 |
| Mileage (4 trips at avg 28 miles) | $75 |
| Subtotal reimbursables | $354 |
Invoice Summary:
| Section | Total |
|---|---|
| Design hours | $4,349 |
| Product purchases (cost + 25%) | $23,063 |
| Reimbursables | $354 |
| Subtotal | $27,766 |
| Sales tax (LA County 9.5%, applied to product subtotal of $23,063) | $2,191 |
| Total | **$29,957 |
| Less deposit applied (April retainer) | -$5,000 |
| Balance Due | **$24,957 |
Payment Terms: Net 7
Method: Wire transfer or check preferred for amounts over $10,000
Sales Tax Notes: Design hours and reimbursables exempt in CA; product purchases subject to applicable sales tax.
This level of detail is what makes design clients comfortable. They see exactly what they paid for in each category, can verify product costs against vendor receipts if requested, and have clean documentation for their own tax purposes.
The biggest pricing decision is the design fee structure. Each works for different client types.
Hourly billing: Best for advisory or consulting work, early-phase concept development before scope is fixed, and clients who want to limit total spend. Disadvantage: clients watch the clock and you have a soft cap on revenue per project.
Flat fee per phase: Best for residential whole-home projects with defined scope. Phase 1 concept = $5,000, Phase 2 design development = $12,000, Phase 3 documentation = $8,000. Clients know what each phase costs upfront.
Square footage: $5 to $25 per sqft of project area, depending on complexity. Common for commercial and large residential. Easy to scope and quote.
Percentage of construction budget: 8 to 15 percent on large projects. Aligns designer interest with project quality. Common for design-build relationships.
Hybrid: Concept work hourly, design development flat fee per phase, installation hourly with cap. Most flexible for client and designer.
Most successful designers use a hybrid model with clearly defined deliverables for each phase. The contract should make the model explicit so there are no billing surprises.
Product procurement is where designer profit lives, but it is also where most billing disputes happen. Be explicit in the contract.
Retail markup (most opaque): Designer purchases at trade pricing (typically 30 to 50 percent off retail) and sells to client at retail or MSRP. Client never sees the trade price. Designer keeps the full spread. This was the dominant model 20 years ago but is increasingly disliked by sophisticated clients who can comparison shop online.
Cost-plus (most transparent): Designer purchases at trade, shows client the trade cost, and adds a defined markup percentage (typically 15 to 35 percent). Both client and designer see the math. Most modern designers use this model because it builds trust.
Design fee + at-cost (cleanest for budget-conscious clients): Designer charges a higher design fee upfront and passes product through at trade cost with no markup. Client pays a clear fee for design services and gets product at the lowest possible price. Best for clients on a budget or who insist on transparency.
Sales tax: Sales tax applies to product purchases based on shipping address. If you order from a New York vendor and ship to a Los Angeles client, LA sales tax applies. Some states have nexus rules that require designers to collect sales tax on products they procure. Many designers use a registered resale certificate to avoid double taxation and let the client pay sales tax on the final delivered price. Consult a CPA familiar with multi-state design billing.
Large interior design projects span months. Bill in phases to avoid carrying client balances for too long.
Typical residential whole-home project phases:
Each phase has a deliverable that triggers billing. Clients know what they get and what they pay. Designers do not carry balances.
Design work is front-loaded. Cash flow requires retainers and milestone billing.
Initial retainer: $5,000 to $25,000 to begin work, applied against the first phase invoice. Non-refundable for cancellations after work begins.
Phase deposits: 50 percent of estimated phase fee due before phase begins, balance due on delivery of phase deliverable.
Product deposits: 50 to 100 percent of product cost due before order placement. Custom items typically require 100 percent because they cannot be returned.
Installation deposit: 50 percent of estimated installation fee due 1 week before install date.
This structure protects you from clients who change their minds, walk away, or slow-pay after work is done. Pre-payment is industry standard for premium design services.
See pricing for Eonebill.ai plans built for interior designers. Features include phased billing, product procurement tracking with markup calculations, reimbursable expense capture, vendor invoice attachment, and multi-state sales tax handling. The right software collapses 10 to 15 hours of weekly admin into 2 hours.
Interior design is a margin business. Polished invoicing is part of the brand. Build yours today in the invoice generator.
Interior design retainer best practices:
A design retainer is the upfront commitment that funds your concept and procurement work before vendor money flows through your account. Three common structures:
Trust account or commingled account: Some states (notably California) require designer-held client funds for product purchases to sit in a separate trust account. Other states allow commingling with operating funds. Always check your state regulations. Even where commingling is legal, separating client funds prevents tax and audit headaches.
Sample 12-month cash flow for a single $150,000 whole-home project:
Designers who maintain 60 days of operating reserve survive the gap between client payment and vendor invoice. See pricing for plans with trust-account reporting and milestone billing automation.
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