What to include on a consulting invoice
- Your business name, address and contact details.
- The client's legal name, billing address and the person or department that approves invoices.
- Invoice number, date, due date and the client's PO number.
- The engagement letter or statement of work it relates to.
- Fees by type (retainer, hourly work or milestone), each on its own line.
- Reimbursable expenses at cost, with receipts attached.
- Payment terms, accepted payment methods and any late fee from your agreement.
Retainers and drawdowns
Consultants use two kinds of retainer. A monthly retainer buys a block of time, say 20 hours for $4,500, billed at the start of each month, with extra hours billed in arrears at your hourly rate. A prepaid retainer is a deposit you bill against:
| Retainer drawdown | Amount |
|---|---|
| Retainer received | $10,000 |
| March: 28 hours at $225 | $6,300 |
| Remaining balance | $3,700 |
Bill the hours as usual, enter the amount drawn from the retainer in the amount-paid field, and note the remaining balance in the invoice notes.
Milestones, expenses and late payments
For project work, bill each milestone when the deliverable is accepted and name the deliverable on the line. Bill reimbursable expenses at cost with receipts unless your contract allows an admin fee, and check the client's travel policy before booking, because many cap hotel and meal costs.
Net 30 is standard for corporate clients. Charge a late fee only if your agreement provides for one and it stays within your state's limits; the late fee calculator works out the amount, and Pro can send automatic reminders. The free consulting invoice is also available as a Word, Excel or PDF download.
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Download this template, prefilled with typical line items. No email needed.
Frequently asked questions
What payment terms do consultants use?
Net 30 is the norm for corporate clients, and some large companies push for net 45 or net 60. Smaller clients often accept net 15. Put the terms in your engagement letter and on every invoice, and ask for a PO number up front if the client uses them, because invoices without one often sit unpaid.
How do I invoice against a retainer?
List the work as usual, then apply the retainer as a payment so the invoice shows the balance due, which may be zero. Note the remaining retainer balance in the invoice notes. When the balance runs low, invoice the client to top it up before starting more work.
Should I mark up reimbursable expenses?
Most consultants bill travel and other reimbursables at cost with receipts, because corporate clients expect it and many contracts require it. If you want to recover the time spent on expenses, agree on an admin fee or percentage in the contract first and show it as a separate line.
Can I add a late fee to a consulting invoice?
Yes, if your contract provides for one and it stays within your state's legal limits. A common approach is a monthly percentage on the overdue balance. State the late fee in your invoice terms, and apply it on a separate line or a new invoice once the due date has passed.
Why do clients ask for a W-9 before paying?
US businesses use Form W-9 to collect your legal name and taxpayer identification number, which they need to file any information returns the IRS requires for payments to you, such as Form 1099-NEC. Many accounts payable teams won't set you up as a vendor without it, so send it with your first invoice.