10 Invoicing Mistakes and How to Fix Them

Invoicing mistakes that slow payment can be caught with a few checks: sending the invoice late, leaving out details the client needs, vague or miscalculated line items, no clear due date, no easy way to pay, and no follow-up. This page lists ten, each with a short fix and a link to the guide that covers it in full, so you can check your own invoices against the list.

Billed publishes this page.

The Ten Mistakes

1. Sending the invoice late

The client can't pay an invoice they haven't received. Send it when the work is delivered, or on a set day each week. See how to send an invoice.

2. Leaving out information the client needs

Your details, the client's details, an invoice number, the invoice date and due date, the line items, the total and how to pay. A missing purchase order number or billing address can send the invoice back to you. See how to create a professional invoice.

3. Vague line items

Consulting with one amount doesn't tell the client what they're paying for. Give each charge its own line with a description, quantity and rate. See how to create itemized invoices.

4. Wrong amounts

A quantity or rate changed without updating the line total, a missing line, or tax applied to the wrong lines. Check the math before you send; the worked example below shows how.

5. No payment terms or due date

Without a due date, there's nothing for the invoice to be late against. State the terms and the actual date. See invoice payment terms explained and what net 30 means. If you offer early-payment discounts or charge late fees, put them in your terms first; see invoice discounts and late fees.

6. Making it hard to pay

Every extra step, such as finding bank details or mailing a check, gives the client a reason to put the invoice aside. Offer at least one way to pay from the invoice itself. See how to accept online payments.

7. Not following up

An unpaid invoice past its due date needs a reminder, then a schedule of follow-ups. See how to write payment reminders, what an overdue invoice is and, for part payments, how to handle partial payments.

8. Inconsistent invoice numbers

Duplicate or out-of-order numbers make invoices hard to find and match. Use one numbering system and don't reuse numbers. See what is an invoice number and invoice numbering best practices.

9. Ignoring the client's process

Some clients need their purchase order number, a specific billing contact or a particular format before they can pay. Ask during onboarding and put their reference on the invoice. See what is a purchase order.

10. Not tracking what's outstanding

If you don't know which invoices are paid in full, paid in part or overdue, you can't follow up on time. Review open invoices each week. See how to track invoices effectively and accounts receivable management.

Worked Example: Catching a Calculation Error

These are sample figures for a fictional invoice.

A freelancer's draft invoice shows:

• Design: 12 hours × $45.00, shown as $504.00
• Copywriting: 4 pages × $60.00 = $240.00
• Stock photo license, at cost: $75.00
• Total shown: $504.00 + $240.00 + $75.00 = $819.00

Checking each line before sending:

• Design: 12 × $45.00 = $540.00, not $504.00 (the digits were swapped).
• Corrected total: $540.00 + $240.00 + $75.00 = $855.00.
• Difference: $855.00 − $819.00 = $36.00 that the draft would have under-billed.

Re-multiply every quantity by its rate and re-add the lines before you send. If the client has already been sent a wrong invoice, send a corrected one rather than editing the old one quietly.

Where Billed Fits

Billed publishes this page. Billed's invoice software page says: "Set a due date on each invoice so your client knows when to pay." It also says: "Invoice reports show which invoices are paid, partially paid or past due, and you can see who owes you money and send them a payment reminder." For payments: "Connect your Stripe account and every invoice you send gets a pay button, so clients can pay by card." For taxes: "Save your tax rates and settings once, and Billed calculates taxes automatically when you create invoices and estimates." See also Billed's invoice templates and invoice generator.

Related Articles

• How to Create a Professional Invoice
• How to Create Itemized Invoices
• Invoice Payment Terms Explained
• How to Write Invoice Payment Reminders
• How to Track Invoices Effectively
• Invoice Numbering Best Practices

Frequently Asked Questions

What should every invoice include?

Your business and contact details, the client's details, a unique invoice number, the invoice date and due date, itemized lines with descriptions, quantities and rates, the total, and how to pay.

How do I avoid calculation errors on invoices?

Re-multiply each quantity by its rate, re-add the lines, and check that any tax applies only to the right lines before you send. In the sample on this page, rechecking one line corrects the total from $819.00 to $855.00.

What should I do if I sent an invoice with a mistake?

Tell the client, and send a corrected invoice that shows the right amounts. Keep a record of both so your books match what was billed.

How soon should I follow up on an unpaid invoice?

Set a schedule before you send the invoice, such as a reminder shortly after the due date and then at regular intervals, and keep a record of each contact.