What a consulting invoice should show
Your contact at the client agreed to hire you. The person who pays you is someone in accounts payable who has never heard of you. Write for them:
- The client’s legal company name and the AP email they gave you, not just your contact’s name.
- PO number or SOW reference. Many companies won’t pay an invoice without one; ask before you send the first bill.
- The period covered: “October 1–31” or “Week of Oct 13”.
- What you billed: retainer, hours, days or milestone, each as its own line with the rate.
- A short description of the work, enough for your contact to approve it without a call.
- Expenses listed separately, with receipts attached if your agreement asks for them.
- Payment terms (net 15, net 30) and your bank details. Add your EIN if the client asks; they’ll also want a W-9 on file before the first payment.
Hourly, day rate, retainer or fixed fee
| Model | How it’s invoiced | Works best for |
|---|---|---|
| Hourly | hours × rate, weekly or monthly, with a log | open-ended advice, small scopes |
| Day rate | days × rate | workshops, site visits, interim roles |
| Monthly retainer | flat fee at the start of each month | ongoing advisory, on-call access |
| Fixed fee / project | split by milestones: kickoff, draft, final | audits, strategy, defined deliverables |
Retainers are usually billed in advance, on the 1st, for that month. If the retainer includes a set number of hours, bill extra hours at the end of the month on the next invoice, at the rate your agreement sets.
Fixed-fee projects are often billed in parts, for example 40% at kickoff, 40% on the draft and 20% on the final report. Send the kickoff invoice before you start work, or as a proforma invoice if the client needs a document to raise a PO.
Typical consulting line items
Rates depend on your field and seniority. These are common ranges for independent business consultants in the US:
- Strategy or operations consulting: $125–$300 per hour
- Day rate, on site: $1,000–$2,500
- Monthly advisory retainer: $1,500–$6,000
- Workshop facilitation, half day: $1,500–$3,500
- Discovery or audit, fixed fee: $2,500–$10,000
- Report or deck preparation: hourly, or part of the project fee
- Travel time: often billed at half rate, if your agreement allows it
- Airfare and hotel: at cost
- Mileage: per mile, at the rate in your agreement
- Software or data purchased for the client: at cost or with an agreed markup
Consulting services aren’t subject to sales tax in most states, but a few states tax some professional services. Check yours before you leave the tax line at zero.
Getting through accounts payable faster
- Get the vendor setup done first: W-9, bank details, PO. Your first invoice can wait weeks if this is missing.
- Send to the AP inbox and copy your contact. AP pays, your contact approves.
- Use one invoice per PO. Mixing two purchase orders on one invoice often gets it sent back.
- Number invoices cleanly. A year prefix such as INV-2026-031 is fine; never reuse a number. More in the invoice number guide.
- Follow up on the due date, not a week later. A polite note with the invoice attached is enough; see the overdue invoice email templates.
Last checked October 23, 2026.