Marketing agencies often run into two invoicing problems: undocumented scope changes that lead to disputes, and slow payments that create cash-flow pressure when payroll and ad spend are due before client checks arrive. A clear invoice, built around the right billing model and separated pass-through ad spend, can reduce disputes and make payment follow-up easier.

Use this page to choose an agency billing model, build a complete invoice, adapt the template, and set payment terms that reduce late payments.

How do marketing agencies typically bill clients?

Three billing models cover most agency engagements, and each shapes the invoice differently.

Monthly retainer. A monthly retainer is a fixed monthly fee for an agreed scope, such as $8,000 per month for SEO, content, and reporting. Retainers smooth out cash flow because the same invoice goes out on the 1st of every month, before work is delivered. They also create the biggest scope-creep risk, because clients often assume "retainer" means "whatever I ask for."

Project-based. A flat fee for defined deliverables: a website launch, a brand refresh, a campaign build. Typical billing is a deposit on signature with the remainder due on delivery, or milestone-based for longer engagements. Invoice structure is simple, but change orders need to be documented and approved before the extra work begins.

Hourly. Common for freelancers and smaller shops, or for ad-hoc work that doesn't fit a retainer. Tracked in 15-minute increments and billed against a published rate card. Hourly is the easiest to explain and the hardest to forecast.

Performance-based and media-spend markup. Some agencies bill a percentage of media spend or tie a portion of fees to results like leads generated, revenue attributed, or ranking improvements. These models work when attribution is clean and the client has enough volume to make percentages meaningful. They fail when reporting is murky or the relationship is new.

The billing model dictates invoice timing. Retainers go out before the period; projects go out at milestones; hourly goes out monthly in arrears. Pick one per engagement and stick to it.

The line item that prevents disputed invoices

Add a line called "Out-of-scope work (pre-approved)" with a $0 default. Every time a client asks for something outside the SOW, you email a one-line approval request, log it against this line, and bill it on the next invoice with the approval email attached. Undocumented scope changes are a common cause of invoice disputes because the client and agency may remember the approval differently. A documented approval trail ends the argument before it starts.

What should a marketing agency invoice include?

Every invoice you send should have these fields. Missing any one of them gives a slow-paying client a reason to delay.

• Your agency's legal name, address, and EIN or tax ID. Use the legal entity, not the DBA, so the client's AP team can match it to your W-9.
• Client name, billing contact, and PO number. Many enterprise clients require a PO number before their AP team can approve an invoice.
• Unique invoice number plus issue date and due date (the actual calendar date, not just "Net 30").
• Itemized services. Campaign or project name, description, hours or quantity, rate, and line total. A line that reads "Marketing services: $8,000" is the fastest way to get a follow-up email asking what you did.
• Pass-through costs on separate lines. Ad spend, stock photography, software licenses, freelance contractors. Each gets its own line so the client can see exactly what was reimbursable versus what was your fee.
• Payment terms, accepted methods, and the late-fee clause. State the terms ("Net 15"), the rails you accept (ACH, card, wire), and the late-fee rate in writing on the invoice itself.

Where can marketing agencies get a free invoice template?

Here's a copy-ready template you can adapt for retainer, project, or hourly billing. Replace bracketed fields with your details.

INVOICE

[Agency Legal Name]
[Street Address, City, State ZIP]
EIN: [XX-XXXXXXX]
hello@[agency].com

Bill To:                              Invoice #: 2025-0142
[Client Company]                      Issue Date: [MM/DD/YYYY]
Attn: [Billing Contact Name]          Due Date: [MM/DD/YYYY]
[Client Address]                      PO #: [if required]

----------------------------------------------------------------
DESCRIPTION                          QTY    RATE        AMOUNT
----------------------------------------------------------------
RETAINER — Month of [Month YYYY]
  SEO + content strategy              1    $6,000      $6,000
  Paid media management               1    $2,000      $2,000

PASS-THROUGH COSTS (reimbursable)
  Google Ads spend (receipt attached) 1    $4,250      $4,250
  Stock photography — Shutterstock    1    $179        $179

OUT-OF-SCOPE WORK (pre-approved)
  Landing page build, approved 3/14   8    $175/hr     $1,400

----------------------------------------------------------------
                                            Subtotal: $13,829
                                            Tax (if applicable): $0
                                            TOTAL DUE: $13,829
----------------------------------------------------------------

Payment Terms: Net 15. Payment due by [date].
Accepted Methods: ACH, credit card, wire transfer.
Late Fee: 1.5% per month on balances 30+ days overdue
(subject to applicable state law and the signed agreement).

Remit ACH/Wire to: [Bank name, routing, account]
Pay by card: [invoice link]

Thank you for your business.

Turn this into a working spreadsheet. Paste the template above into ChatGPT or Claude with a prompt like: "Convert this invoice into a fillable Google Sheet with formulas for line totals, subtotal, tax, and total. Add a second tab for a project-based version with 50% deposit and 50% on delivery." You'll get back a spreadsheet you can save as Excel, share as Google Sheets, or export to PDF.

Retainer version vs. project-based version

For a retainer, the description block is a single line per service category, billed monthly in advance, with the period explicitly stated ("Month of October 2025"). For a project, replace the retainer block with milestones:

PROJECT — Website Redesign (SOW dated 9/12/2025)
  Milestone 1: Discovery + wireframes (50% deposit)   $12,500
  Milestone 2: Design + development (40%)              $10,000
  Milestone 3: Launch + handoff (10%)                  $2,500

For hourly work, swap in a time-tracking block with date, task, hours, and rate per line. Agencies commonly round to the nearest 15 minutes (0.25 hr).

Put taxes on a separate line below the subtotal instead of baking them into rates. Discounts (early-pay, volume) appear as a negative line item with the reason stated.

How do you invoice for retainers, projects, and media spend?

Retainers. Issue on the 1st of the month, due Net 15. Bill before services are delivered, since that's the point of a retainer. Define rollover rules in the SOW: unused hours either expire at month-end or roll for 30 days with a cap. Without a rollover rule, clients may expect unused hours to accumulate and create a large unplanned workload later in the year.

Project work. Marketing agencies can reduce project-payment risk by requiring a signed agreement and a cleared deposit before project work begins. A deposit-plus-final-payment structure is common, often split 50% on signature and 50% on delivery; for longer or larger engagements, a three- or four-milestone split is more typical. For new or large projects, wait until the deposit clears before starting work.

Media spend. Bill ad budget on a separate line from your management fee, every time. Mixing them hides your margin, makes the invoice harder for the client's finance team to approve, and creates bookkeeping headaches when reimbursable spend gets recorded as agency revenue. Attach the platform receipt (Google Ads, Meta, LinkedIn) so the line is auditable.

Change orders. Anything outside the SOW gets a one-page addendum signed by the client before the work happens. Reference the addendum number on the next invoice. If the client has not approved the change order, do not start the extra work or add it to the invoice.

What payment terms help marketing agencies get paid faster?

Net 15 vs. Net 30

Many agencies use Net 15 or Net 30. Enterprise AP departments often expect Net 30, but smaller agencies can push for Net 15 on new engagements and reserve Net 30 for clients with a clean payment history. The shorter the terms, the smaller the working-capital gap between paying your team and getting paid.

Late fees

Some agencies use a 1.5% monthly late fee, but late-fee rules vary by state and contract type. Include any late-fee clause in the signed agreement and on the invoice itself, and confirm enforceability with a qualified legal or tax advisor before applying it. Waiving the fee once turns it into a suggestion, so apply it consistently when you do enforce it.

Accepting ACH, card, and wire

• ACH is often less expensive than card payments, and standard ACH credit transactions generally settle within one to two business days, with same-day settlement available for eligible transactions. ACH is a sensible default for retainer clients.
• Card payments can be convenient for clients and may authorize quickly, but they usually cost more than ACH, and settlement timing depends on the processor.

You may be able to pass the fee through as a surcharge in some states, but disclose it.

• Wire transfers can clear same-day for domestic transfers and are often used for deposits over $10,000. Outgoing wire fees vary by provider; incoming domestic wires are free at Novo.

The three-touch reminder schedule

1. Day of due date: Friendly automated email. "Invoice #2025-0142 is due today, here's the payment link."
2. Day 7 past due: Direct email from the account owner. Reference the invoice, restate the late-fee clause, ask if anything is blocking payment.
3. Day 14 past due: Phone call to the billing contact, followed by a written notice that the late fee will apply at day 31 and that work will pause until the balance clears.

A consistent reminder schedule gives clients fewer chances to miss the invoice and helps your team follow up before the balance becomes seriously overdue.

How can marketing agencies send and track invoices with Novo?

Novo combines business checking and invoicing in a single platform, so you do not have to operate a separate SaaS subscription on top of your business checking account.

• $0 monthly fee, unlimited invoices. Send as many invoices as you need each month. Billing 30 retainer clients costs the same as billing three.
• Clients pay from an invoice link by ACH or card, and payments can land in the same Novo business checking account you use to run your business — no transfer step between an invoicing app and your business checking account.
• Free incoming domestic wires. Free incoming domestic wires can help when an enterprise client pays a large project deposit by wire, because Novo does not charge an incoming domestic wire fee.
• QuickBooks integration for reconciliation, plus the other tools on Novo's current integrations list. Invoices, payments, and account transactions sync without manual export.
• No cash deposits. Novo does not accept cash, which is rarely an issue for marketing agencies since clients pay by ACH, card, or wire.

With a traditional business checking account, many agencies pay for separate invoicing software each month and then reconcile payments back to the account by hand. Novo includes invoicing with a Novo business checking account and has no monthly fee.

What invoicing mistakes should marketing agencies avoid?

Vague line items. "Marketing services: $8,000" invites questions. "SEO + content strategy (October 2025 retainer): $8,000" answers them.

Mixing ad spend and management fees. A line that reads "Google Ads campaign: $10,000" hides whether $9,000 was reimbursable spend and $1,000 was your fee, or the reverse. Split them. Always.

No due date or late-fee clause on the invoice. "Net 30" without a specific calendar date pushes the math onto the client and gives them an excuse to pay late. The late-fee clause has to be on the invoice itself, not just the SOW, for it to stick.

Inconsistent invoice numbering. Using random numbers, leaving gaps in the sequence, or restarting at 001 every January can complicate bookkeeping, audits, and client payment tracking. Use a simple sequential format (2025-0001, 2025-0002) or year-month-sequence (2025-10-001).

Frequently asked questions

Do marketing agencies charge sales tax on services?

Sales-tax rules for marketing and advertising services vary by state and by service type (creative work, media buying, and printing are often treated differently). Check your state department of revenue or ask a CPA before invoicing clients across state lines. When in doubt, separate taxable and non-taxable services on the invoice.

How do I invoice for ad spend I paid on a client's behalf?

List the ad spend as a separate pass-through line item, attach the platform receipt (Google Ads, Meta, LinkedIn invoice), and bill your management fee on its own line. Keeping ad spend on a separate pass-through line makes the invoice easier for the client's finance team to review and gives your bookkeeper clearer documentation. Ask a CPA how to record reimbursements for tax purposes — our marketing agency business expenses guide covers common categories.

What payment terms should a new agency offer?

Start with Net 15 and require 50% upfront on first projects until the client has a payment history of three on-time invoices. Once they've earned it, you can extend to Net 30. Enterprise clients with formal AP processes often require Net 30 or Net 45 by policy. In those cases, negotiate a 2% early-pay discount for payment within 10 days.

How do I handle a disputed retainer invoice?

Within 24 hours, send the original SOW, that month's deliverables log, and the invoice with line items mapped to deliverables. Then propose a 15-minute call to walk through it. Disputes often come from a memory gap rather than bad faith, so showing the work resolves most of them before they escalate. If the dispute is over scope, reference the signed change-order addendums; if there are none, that's a process fix for next month.

What invoice software do marketing agencies use?

Agencies typically use standalone invoicing software (like FreshBooks or HoneyBook), accounting suites (like QuickBooks or Xero) with built-in invoicing, or business checking accounts with invoicing included (like Novo). Standalone tools have the most invoicing-specific features; account-integrated invoicing removes the transfer step and the separate subscription.

Should I send invoices as PDFs or use a payment link?

Both. Attach a PDF for the client's records and AP filing, and include a payment link in the email body for one-click ACH or card payment. PDF-only invoices can make clients take an extra manual step before payment, while a payment link gives them a direct way to pay by ACH or card.