How to Invoice as a Consultant
What a consulting invoice needs, the order to fill it in, which terms to set, and how to follow up when a client pays late.
A consulting invoice should let the client's approver match every charge to the work they signed off on. Name the engagement, give each fee its own line, state when payment is due, and keep reimbursed costs apart from your fee.
The US Bureau of Labor Statistics, in its Occupational Outlook Handbook (last modified August 27, 2026), states "Management analysts recommend ways to improve an organization’s efficiency." It also says "Management analysts may travel frequently to meet with clients." When your contract says the client pays for that travel, bill it as its own line rather than inside your fee.
Worked example (these are sample figures): a consultant bills a fixed fee of $4,800.00 for a pricing review. The client also reimburses one train ticket of $180.00, recorded in Billed as an expense. Billed's help center says "If there are any unbilled expenses of a particular client, you can add these expenses to the client's next invoice." and "The expense will appear as a line item in the invoice." The invoice has two lines: $4,800.00 + $180.00 = $4,980.00, payable within 15 days.
Step-by-step invoicing guide
- 1
Name the engagement
Put the client's legal name, the engagement or project name, and any purchase order or reference number the client gave you near the top, so their approver can match the invoice to the work.
- 2
Give each fee its own line
List the fixed fee, each block of hours and each reimbursed cost separately, with a short description. Billed's help center says you can "fill this section to charge against new items and services".
- 3
Bill hours from your time log
For hourly work, Billed's help center says "Billed allows you to generate invoices against billable time log entries." Billed's time tracking page says "Create an hourly rate project, set its hourly rate, and Billed tracks the charge for each task as you log it."
- 4
Add reimbursed costs
Record travel and other costs the client pays for as expenses. Billed's help center says "If there are any unbilled expenses of a particular client, you can add these expenses to the client's next invoice."
- 5
Set the due date and terms
Billed's invoice software page says "Set a due date on each invoice so your client knows when to pay." Match the terms your contract sets, for example 15 or 30 days.
- 6
Send it, then follow up
Billed's invoice software page says "When the invoice is ready, send it to your client by email." Billed's help center says "You can set a schedule of payment reminders before and after the invoice's due date."
Tips for consultant invoicing
- Use the same names for workstreams on the invoice as in your proposal, so the approver doesn't have to translate.
- Ask a new client for their accounts payable contact and any purchase order number before you send the first invoice.
- For a fixed fee paid in stages, use one invoice with several installments; Billed's help center says "Add a percentage or flat amount and the due date for each installment."
- Keep the receipt with each reimbursed cost: Billed's expenses page says "An expense in Billed records who you paid, when, how much and which category it belongs to, with the receipt attached to the same entry."
- For a client abroad, invoice in the currency your contract names: Billed's invoice software page says you can "Invoice customers in multiple currencies, choosing a different currency for each invoice or customer."
Common invoicing mistakes to avoid
- Sending one lump sum with no breakdown, so the approver may have to write back and ask what it covers.
- Folding reimbursed travel into the fee instead of showing it as its own line.
- Leaving the due date off, so the client's payment run may have nothing to go by.
- Billing a long fixed-fee engagement only at the end when the contract allows stage payments.
- Waiting weeks after a missed due date before the first follow-up.
How this works in Billed
Line items for each fee
Billed's help center says you can "fill this section to charge against new items and services".
Invoices from tracked time
Billed's help center says "Billed allows you to generate invoices against billable time log entries."
Unbilled expenses on the next invoice
Billed's help center says "If there are any unbilled expenses of a particular client, you can add these expenses to the client's next invoice." and "The expense will appear as a line item in the invoice."
Stage payments on one invoice
Billed's help center says "Clients can pay several installments against a single invoice." and "You can make unlimited installments. However, the sum of all installments should be equal to the total balance of the invoice."
Scheduled payment reminders
Billed's help center says "You can set a schedule of payment reminders before and after the invoice's due date." It also says "You can send up to three reminders."
Frequently asked questions
Start Invoicing With Billed
Set up your account and send your first invoice with Billed.
At a glance
| Charge | How to show it on the invoice |
|---|---|
| Fixed project fee | One line, or stage payments on one invoice |
| Hourly work | An invoice generated from your time entries |
| Reimbursed travel | Its own line, from the client's unbilled expenses |
| Late payment | Reminders scheduled around the due date |
When this isn't for you
If your current way of invoicing clients already works, there's no need to switch.