What is Interim Invoice?
An interim invoice is a progress or mid-project invoice sent before the final invoice. Learn when to use interim invoices, what they should include, and how they help freelancers maintain cash flow on long projects.
What Is an Interim Invoice?
An interim invoice (also called a progress invoice or partial invoice) is an invoice sent partway through a project to bill for work completed so far, rather than waiting until the entire project is complete. It's one of the primary tools for managing cash flow on longer engagements. Think of interim invoicing as collecting rent — just as a landlord collects monthly rent for an apartment you've been living in all month, you collect payments for work as it's completed, not after months of waiting. Interim invoices are essential for: - Cash flow — You get paid while working, not after - Risk reduction — You're not exposed for months of unpaid work - Client confidence — Regular invoices with documentation show progress - Milestone-based projects — Payments tied to deliverables, not just time
When to Use Interim Invoices
| Situation | Use Interim Invoices? | |---|---| | Project longer than 30 days | Yes — at minimum monthly | | Fixed milestone deliverables | Yes — invoice at each milestone | | T&M or hourly project | Yes — monthly or bi-weekly | | Retainer work | Yes — at start of each period | | Fixed-price project | Yes — tie to milestones | | One-week project | No — invoice at completion |
What to Include on an Interim Invoice
An interim invoice should clearly show: 1. This is a progress/interim invoice — Make it clear this is not the final invoice 2. Project name and phase — What portion of the work is this? 3. Work completed this period — Description of deliverables 4. Percentage complete — If applicable 5. Original contract value — Total project value 6. Amount billed to date — Cumulative previous invoices 7. Amount due this invoice — This period's billing 8. Remaining balance — What will be invoiced later Interim Invoice Template Structure > INTERIM INVOICE #3 (not final) > > Project: Website Redesign — Acme Corp > Invoice Date: March 15, 2026 > Billing Period: March 1-14, 2026 > > Contract Value: $48,000 > Previously Invoiced: $19,200 (Invoice #1: $9,600 + Invoice #2: $9,600) > > This Invoice: > - Phase 2 Deliverables: Homepage, About, Contact pages (design + development) > - Work completed as specified in Exhibit A > - Amount Due: $14,400 > > Total Billed to Date: $33,600 (70%) > Remaining Balance: $14,400 (30% — due upon project completion)
Example: Interim Invoices on a 4-Month Project
Project: Mobile app development — $80,000 total Billing: Monthly interim invoices Month 1 (Deposit + Discovery): - Deposit: $16,000 (20%) — upon contract signing - Discovery phase: $8,000 (10%) - Invoice #1: $24,000 Month 2 (Design phase): - Design complete: $24,000 (30%) - Invoice #2: $24,000 Month 3 (Development phase — partial): - Development 50% complete: $20,000 (25%) - Invoice #3: $20,000 Month 4 (Completion): - Development complete + launch: $12,000 (15%) - Invoice #4 (Final): $12,000 Total: $80,000 — invoiced progressively throughout the project
Interim Invoice vs. Progress Invoice vs. Partial Invoice
These terms are often used interchangeably, but there are subtle differences: | Term | Typical Meaning | |---|---| | Interim invoice | Mid-project invoice; implies more work remains | | Progress invoice | Based on percentage of work completed | | Partial invoice | Invoice for part of what you're owed; may or may not be milestone-based | | Draw request | Specifically in construction/escrow context | In practice, freelancers use all three terms somewhat interchangeably.
Interim Invoicing Best Practices
1. Define the schedule in your contract — "Invoice monthly on the 1st" or "Invoice at each milestone" 2. Make it clear this is interim, not final — Reduces confusion 3. Document work completed — Attach a brief progress report or summary 4. Show running totals — Client knows how much has been billed and what remains 5. Invoice on time, every time — Consistent interim invoicing keeps cash flowing
The Bottom Line
Interim invoicing is the discipline of billing regularly throughout a project — not just at the end. It keeps cash flowing, reduces your risk exposure, and demonstrates progress to clients. Define your interim billing schedule in the contract before starting work, and stick to it. (Bill projects correctly →) (Understand progress billing →) (Manage milestones →) Key Takeaways: 1. Interim invoices bill for work completed mid-project, not just at the end 2. Essential for projects longer than 30 days to maintain cash flow 3. Clearly mark interim invoices as "not final" and show remaining balance 4. Define the interim billing schedule in your contract upfront 5. Document work completed with each interim invoice — builds client confidence Invoice progressively, get paid on time — Try Eonebill Free Eonebill's project billing features handle milestone tracking and interim invoicing automatically — so you bill regularly and never work for free. View Pricing → | Glossary Home → | Home →