What’s the Best Subject Line for Sending an Invoice? (5 Options)

Email subjects for invoices aren’t all that different from subject lines in any other scenario.

There’s just one hang-up: Sending an invoice can be a little awkward. 

Which means lots of people have a hard time knowing what to say when sending an invoice via email.

Below, you’ll find 6 perfectly acceptable email subject line options for the next time you need to send an invoice.

And if you’d rather not worry about it, just use an invoicing app which will handle all your communication for you. The one we recommend the most is FreshBooks because they follow-up with clients who “forget” to pay. 

Here are our top 6 email subject line recommendations when sending an invoice:

1. “Invoice ####”

The first and most basic email subject for invoicing is to just write Invoice #### where the ####s are, of course, the number of the invoice you’re sending. It would look something like this:

Example subject line: Invoice #1234

This email subject line works when sending invoices because it’s basic, simple, and to-the-point. Of course, it’s also a bit cold. 

We recommend using this email subject for invoicing an accounts payable department or some other faceless organization.

If you’re sending an invoice via email to someone you’re building a relationship with, like a client, try a warmer email subject line for invoicing them instead (more below).

2. “Invoice #### Due. Thank you!”

To warm it up a bit, you can make your email subject line a bit more conversation (and grateful) by adding a simple “thank you” to your email subject line when sending an invoice.

Example subject line: Invoice #1234 Due. Thanks a bunch!

This keeps it very straightforward and clear, but also let’s your client know you’re grateful for both their business and a prompt payment of your invoice.

3. “Here’s your invoice (####)”

To warm up even more, make your email subject line for invoices more conversational. If you were delivering your invoice in person instead of emailing an invoice, you’d never hand a piece of paper to someone and say “Invoice #1234.”

Instead, you’d probably say something like “Here’s that invoice we discussed.” Which is exactly what’s happening in this email subject line for invoices.

Example subject line: Hey! Here’s the invoice we talked about (#1234)

4. “Sending invoice as requested (####)”

If you’re not exactly friendly (or casual) with the person you’re sending the invoice to, you may want to just consider remind them, in your email subject, that you had previously discussed the invoice you’re sending them.

Example subject: Sending Invoice #1234 as requested

This can also help lessen the awkward “where did this invoice come from?” moment some clients experience when they’re dealing with lots of different contractors.

5. “New invoice from [company name]”

Another way to help your clients stay organized and remind them who’s sending the invoice via email is to include your company name (or your personal name if you’re a freelancer operating under your own name).

Example email subject: New invoice from Jean Yves Design Co.

Or any combination of the above choices…

Of course, you can combine any of the above ideas to form the ideal email subject line for sending invoices. 

Figuring out what to say when sending an invoice via email is a matter of finding your own style, experimenting, and adjusting as needed.

What about past-due or overdue invoices?

If you have a collection of past-due or overdue invoices, try using one of our 3 free past-due invoice emails in order to get paid what you’re owed asap.

Bonus resources for better invoicing:

If you’re going to be sending more than one invoice to your clients, we suggest not necessarily always sending manually via email. Sometimes asking for payment can come off as rude if not handled perfectly which is an added stress you don’t need. 

Instead, try one of these invoicing tools we highly recommend:

FreshBooks (try free 30 days)

We’ve been working with freelancers (and freelancing ourselves) for over a decade. And, by far, the most popular invoicing tool we hear about from our community is FreshBooks.

With FreshBooks, you can generate invoices in 30 seconds or less and automate follow-up emails to remind your clients their invoice is due. All via email without manual work from you.

Andco (try free with one client)

Another great option for sending invoices to your clients and managing all of the other aspects of your freelance business is And.co. With And.co, you can send freelance proposals, generate invoices, get paid quickly and manage your time and tasks.

Honeybook (try free 30 days)

Another great option for sending invoices to your clients (and managing whether your invoices get paid) is Honeybook. It’s also got some great bookkeeping, reporting, time-tracking, and project management options. 

Bonsai (try free for 14 days)

Finally, we highly recommend one last invoicing tool for freelancers called Bonsai. Built by freelancers, for freelancers Bonsai is an all-in-one business suite for managing every aspect of your freelance business.

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