Invoice generator for consultants

Consulting invoices for retainers, hour blocks and expenses

Show what the retainer covers, which hours ran over, and which travel costs you're passing through at cost.

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Consulting engagements tend to follow a few patterns: a monthly retainer for ongoing advice, a prepaid block of hours drawn down over time, or a fixed-fee project with defined deliverables. On top of that, there are often reimbursable expenses like travel, which most clients expect to see itemized and billed at cost.

Your client is usually a business with its own approval process, so the invoice should include the engagement name, the statement of work or PO reference, and the billing period. That's what gets it approved without a back-and-forth.

Harbor Point Advisory LLC

60 State St, Suite 700, Boston, MA 02109

invoices@harborpointadvisory.example.com

(617) 555-0147

Invoice

No.: HPA-2026-10
Date: Oct 1, 2026
Due date: Oct 31, 2026
Engagement: Supply chain review, SOW #2026-03
PO #: NMS-10288

Bill to

Dana Whitfield, COO

Northshore Medical Supply

15 Commerce Way, Woburn, MA 01801

dana.whitfield@northshoremed.example.com

Terms

Net 30

Line items
Service	Hours	Rate	Amount
Operations advisory retainer, October 2026 (includes up to 20 hours) 1 × $6,500.00	1	$6,500.00	$6,500.00
September hours beyond retainer (logs attached) 6.5 × $275.00	6.5	$275.00	$1,787.50
Airfare BOS-ORD for supplier site visit, 9/22, at cost 1 × $412.60	1	$412.60	$412.60
Hotel, 1 night, Chicago, at cost 1 × $289.00	1	$289.00	$289.00

Subtotal: $8,989.10
Tax: $0.00
Total due: $8,989.10

Notes

Expenses are billed at cost; receipts available on request. The retainer for November will be invoiced on November 1.

A monthly consulting retainer billed in advance, with last month's overage hours and travel expenses passed through at cost.

What consultants invoice for

Monthly retainers
Bill the same retainer each month, and list any hours beyond the included amount as a separate overage line.
Prepaid hour blocks
Invoice a block of hours up front, then note on later invoices how many hours have been used and how many remain.
Project-based engagements
Bill a fixed fee by phase, such as discovery, recommendations and implementation support.
Reimbursable expenses
Pass through airfare, lodging and mileage at cost, with receipts kept on file in case the client asks.

What to put on a consultant invoice

Fields for a consultant invoice
Field	Why it matters
Engagement or SOW reference	Ties the invoice to the signed statement of work so the client's finance team can approve it quickly.
Billing period	Retainers and hourly work need a clear date range, like "October 2026" or "Sept 15-30".
Hours used and remaining	For hour blocks, showing the running balance keeps the client informed and sets up the next renewal.
Expenses listed separately	Keeping reimbursables apart from fees makes it clear you're not marking them up, if your agreement says at cost.
Client contact and PO number	Name the person who approves the invoice and include any PO number their accounts payable team requires.

Billing tips

Bill retainers at the start of the period, not the end. That's the point of a retainer.
Spell out in your agreement whether expenses are billed at cost or with an admin fee, and label the invoice lines to match.
Keep receipts for every reimbursable. The BePaid app can scan receipt photos and store them with your expenses.
For hour blocks, show hours used and hours remaining on each invoice so the renewal conversation comes naturally.

Ready to bill a job?

The consulting template comes set up with the fields above.

Create a free consultant invoice

Consultants: invoicing questions

How do I invoice a consulting retainer?

Invoice the fixed retainer amount at the start of each period, describe what it covers, and bill any extra hours or out-of-scope work on separate lines. Most retainers are billed monthly in advance.

Should I mark up expenses?

That depends on your agreement. Many consulting contracts specify expenses at cost, and clients generally expect that unless a markup or admin fee was agreed in advance. Whatever you choose, label it clearly.

What payment terms are normal for consultants?

Net 30 is common for business clients, and some larger companies push for Net 45 or Net 60. Retainers are often due on receipt or within 15 days. See our guide to payment terms for the tradeoffs.

Do I need to attach time logs?

Not always, but for hourly or overage billing it helps. A short summary of hours by date and task answers most questions before the client asks.

BePaid: Free Invoice Maker 2Go

Free on the App Store · iPhone

The BePaid app creates the final, clean PDF invoice, and your first invoice is free. It also keeps track of who has paid.

Invoices & quotesCreate both, and turn an accepted quote into an invoice in a tap.
Clients & saved itemsKeep customer details and your usual services ready to reuse.
Payment statusSee what's paid, unpaid and overdue at a glance.
Expenses & receiptsSnap a photo of a receipt and log the expense.
Your brandAdd your logo and signature, and pick from 8 invoice styles.
Send as PDFShare the finished invoice by email or message from your iPhone.