Invoicing Software for Interior Designers

Interior designers bill creative services through three primary fee structures: flat project fees, hourly rates, and percentage-of-project cost. Many firms combine methods — a flat fee for concept and design development, then a percentage on procurement. Billed supports all three models on a single project record so your invoicing reflects the actual terms of your letter of agreement.

Flat fees invoice against milestones: concept presentation, final design development package, specification book delivery. Hourly billing tracks time for shopping trips, site visits, and client meetings that fall outside the base scope. Percentage-of-project billing calculates your fee as an agreed percentage of total FF&E and construction costs, updating as the project budget evolves.

This flexibility matters because interior design clients range from residential homeowners who expect a fixed price to commercial developers who negotiate percentage-based compensation. Rather than forcing every engagement into one billing template, Billed lets each project invoice match the fee structure you actually agreed to — reducing client confusion and payment delays.

Procurement is where interior design firms generate significant revenue. You source furniture, lighting, textiles, wallcoverings, and accessories at trade pricing through design-center showrooms and direct manufacturer accounts, then sell to clients at a marked-up retail or net-plus percentage. Protecting that trade discount margin while presenting clear, defensible invoices is a constant balancing act.

Billed lets you set markup percentages per line item or per vendor category. A sofa purchased at trade for $3,200 invoices to the client at your agreed markup — whether that is net-plus-30%, cost-plus, or full retail — without exposing your wholesale cost on the client-facing document. Internal project records retain the true cost for your own margin analysis.

This separation is critical for maintaining vendor relationships and professional standards. Trade accounts depend on confidentiality agreements; exposing wholesale pricing to end clients can violate showroom policies and devalue your sourcing expertise. Billed keeps the numbers your client needs visible and the numbers that are your business private.

Interior design projects move through distinct phases: programming and concept development, design development with mood boards and material palettes, procurement and FF&E ordering, receiving and installation coordination, and final styling. Each phase carries different cost structures and cash flow requirements.

Billed lets you create phase-based invoices tied to a single project. Invoice the design retainer at engagement, concept fees upon mood board and floor plan presentation, procurement deposits before placing vendor orders, and installation coordination fees as deliveries are scheduled. Final styling and accessory placement invoice upon project completion.

Phased billing solves the cash flow problem that plagues design firms: vendors require deposits 8-16 weeks before delivery, while clients often expect to pay only when furniture arrives. By collecting procurement deposits in advance — timed to your vendor payment obligations — you avoid funding a client's renovation with your own working capital. Each invoice documents the phase completed, creating a clear payment trail that both parties can reference throughout a project that may span six months to two years.

The FF&E schedule is the backbone of an interior design project's financial documentation. It catalogs every furniture piece, fixture, and equipment item with specifications, vendor source, trade cost, client price, lead time, and room assignment. Your invoicing needs to reflect this level of detail without overwhelming the client.

Billed lets you structure procurement invoices that reference FF&E line items by room or area — living room seating group, primary bedroom case goods, kitchen pendant lighting. Each line item carries a description, quantity, unit price after markup, and delivery status. When a client reviews the invoice, they see exactly what they are paying for and where it goes in their space.

This specification-level detail also protects your firm during disputes. If a client questions a charge, the invoice line item traces back to the approved specification book entry, the vendor purchase order, and the client's sign-off on that selection. The billing document becomes part of the project's design documentation rather than a disconnected accounting artifact.

Installation day involves receiving agents, white-glove delivery teams, electricians for hardwired fixtures, art installers, and custom window treatment fabricators — all on a coordinated schedule. These third-party costs, combined with your own installation oversight fee, need clear documentation on the client invoice.

Billed lets you itemize installation charges by trade or service: delivery and placement, electrical rough-in and trim, drapery installation, art hanging, and your project management supervision. When you coordinate a receiver warehouse for furniture staging before a large residential install, that warehousing cost appears as its own line item rather than hidden in a vague "installation" lump sum.

Transparent installation billing reduces the sticker shock that derails final payments. Clients who see a single $18,000 installation charge push back; clients who see white-glove delivery at $4,200, electrical at $3,800, window treatments at $2,600, art installation at $1,400, and project supervision at $6,000 understand the scope of coordination involved. Detailed breakdowns accelerate approval and protect your final payment timeline.

Interior design profitability varies dramatically by engagement type. A full-service residential project billing flat fees plus procurement markup operates on different margins than an hourly commercial furniture specification project. Without tracking revenue against hours invested per project, firms cannot identify which service models and client segments sustain the business.

Billed tracks billed revenue, procurement margins, and logged hours per project, giving you a profitability view that distinguishes design-fee income from markup income. A residential project generating $28,000 in design fees and $42,000 in procurement markup over 380 hours tells a different margin story than a commercial project producing $65,000 in hourly fees over 290 hours with no procurement component.

This data informs how you structure future engagements. If procurement-heavy residential projects consistently yield stronger margins than hourly commercial work, you can prioritize those opportunities. If design development phases regularly exceed budgeted hours, you adjust flat fees or scope definitions on new proposals. Over time, your firm builds a dataset of actual project economics that replaces intuition with evidence.