Consulting Invoice Template
Consulting engagements combine a fixed retainer, day-rate overflow work and pass-through expenses that must be reimbursed at cost. This template separates all three, plus a PO reference, so procurement can match it to the contract and approve fast.
Last reviewed 2026-07-01
Template preview
- From:
- Northwind Advisory LLC · billing@northwind.co
- Bill to:
- Client Co · Attn: Procurement · po@client.com
- Invoice #:
- NW-2026-042
- PO number:
- PO-88231
- Due date:
- 2026-07-31 (Net 30)
| Description | Qty | Rate | Amount |
|---|---|---|---|
| Monthly strategy retainer | 1 | $6,000.00 | $6,000.00 |
| Additional advisory days | 2 | $1,500.00 | $3,000.00 |
| Reimbursable travel (at cost) | 1 | $742.10 | $742.10 |
| Subtotal | $9,742.10 | ||
| Tax (services, if applicable) | $0.00 | ||
| Total due | $9,742.10 | ||
How to fill in each field
Retainer line
Bill the fixed monthly retainer as one line, referencing the contract.
Common mistake: Breaking a flat retainer into hours — it invites scope creep arguments.
Overflow / day rate
Show work beyond the retainer at the agreed day rate as separate lines.
Common mistake: Absorbing overflow into the retainer and quietly under-billing yourself.
Reimbursable expenses
List pass-through expenses at cost and attach receipts. Never mark them up unless the contract allows.
Common mistake: Marking up expenses without disclosure — a common cause of disputed consulting invoices.
PO number
Include the client's purchase-order number if they use one; AP will reject invoices without it.
Common mistake: Omitting the PO reference and having the invoice bounce back unpaid.
Related templates & variants
This is the consulting variant of our main invoice. Billing pure hourly work? Use the freelance version. Selling software subscriptions? See the SaaS version.
Download a professional invoice template in Word, Excel, CSV or Google Docs. Includes a field-by-field guide, tax-line examples and common billing mistakes to avoid.
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A SaaS invoice template built for recurring MRR, per-seat pricing and mid-cycle proration. Download in Excel or Word, with a field guide for subscription billing.
Recommended tools
Prefer software to a file?
Retainer tracking and expense capture with receipts attached to invoices.
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Frequently asked questions
Should consulting invoices include a PO number?+
If the client issued a purchase order, yes — most enterprise AP systems will not pay an invoice that omits the matching PO number.
Can I mark up reimbursable expenses?+
Only if your contract explicitly allows it. The default expectation is that pass-through expenses are billed at cost with receipts attached.
How do I invoice a monthly retainer?+
Bill the retainer as a single fixed line each period, then add any agreed overflow work at your day rate on separate lines.
Sources & further reading
- How to invoice for consulting services (Stripe)— stripe.com
- Consulting invoice templates (QuickBooks)— quickbooks.intuit.com
- Consulting invoice template (Xero)— xero.com
We review authoritative guidance when building each template. Links are for reference only.