The one line that gets a NET 60 invoice paid in 15 days

Your $18k monthly retainer hits the AP queue and joins every other invoice your client received that week. NET 60 means you could be waiting until day 58 for a bank transfer that should have left on day 30. There is no need to renegotiate the contract to fix this. You just need to add one line.

What the line actually says

The line is a dynamic discount term, sometimes called an early-payment discount or a prompt-payment incentive. It looks like this:

2/10 Net 60 — 2% discount if paid within 10 days; full amount due by day 60.

That's the standard notation. Some clients and some invoice templates use plain English instead:

"A 2% discount applies if payment is received within 10 days of the invoice date."

Both say the same thing. The client's AP team reads it, flags it for their treasury desk, and decides whether saving 2% is worth releasing funds early. For a $18k retainer, 2% is $360. Many AP departments are authorised to approve early-pay discounts under $500 without escalation. You are making their decision easy.

Why this does not require a contract change

Your retainer agreement specifies NET 60 as the maximum payment window, not a minimum holding period. Adding a voluntary early-payment option does not alter that obligation. You are not asking the client to waive their terms; you are offering them a financial incentive to beat them. No legal amendment needed.

If a client's procurement team ever pushes back, the cleanest response is: "The contract term still applies. This is an optional discount, not a revised payment schedule." That usually ends the conversation.

Calibrating the discount so it actually works

The 2% figure is not arbitrary. It maps to an annualised return of roughly 36% on the freed-up cash (2% over 50 days, annualised). Corporate treasury teams know this math. Even a conservative 1.5% early-pay discount annualises above most short-term investment returns, which is why AP departments are motivated to act on it.

A few calibration rules:

• Retainers under $10k/month: 2% works; anything higher feels generous to the point of suspicion.
• Retainers $10k–$25k/month: 1.5%–2% is the standard range. Do not go below 1% or the treasury math stops pencilling out.
• Clients on NET 90: Offer 2.5% for 15-day payment. The longer their standard window, the more valuable the discount is to both sides.

One important check: confirm your margin absorbs the discount. A $20k retainer at 2% costs you $400. If that month included significant contractor pass-throughs, calculate the discount on the net margin, not gross.

Placing the line on the invoice

Location matters more than most consultants realise. The line needs to be somewhere the AP clerk sees it before they file the invoice into a 60-day queue. Three spots that work:

1. Payment terms field (the formal field most invoices have): Replace "NET 60" with "2/10 NET 60".
2. Notes or memo section, immediately below the total: Write it in plain English, one sentence, no legal language.
3. Email body, when you send the invoice link: "As a reminder, a 2% discount applies to this invoice if settled by [date 10 days out]. Happy to confirm bank details if that helps your team move quickly."

The email mention is often the most effective trigger because it lands in the inbox of the person who forwarded it to AP, and they can act as an internal champion.

The one scenario where this line backfires

If your retainer agreement includes a clause that says the client may deduct discounts or credits from future invoices without approval, a blanket early-payment line could be misread as an always-available credit. Check for that language before you add the term. It is rare in consulting agreements but common in vendor supply contracts.

The fix is a small qualifier: "Discount applies only to invoices where payment is confirmed received within 10 calendar days of invoice date." One sentence eliminates the ambiguity.

What to do if the client ignores the discount

Not every client will take the bait on the first invoice. Large corporates have AP cycles that are semi-automated: invoices received between certain dates batch into certain payment runs. Your discount window may simply not align with their next run.

The move here is not to lower the discount; it is to shift your invoice send date. If you know their AP runs on the 1st and 15th of the month, send your invoice so the 10-day window straddles one of those dates. A retainer invoice sent on the 22nd gives them a discount window expiring on the 1st, exactly when their AP is already processing payments. That alignment turns a passive line item into an active prompt.

The compounding effect across a year

One client taking the early-pay discount on a $15k monthly retainer turns 12 invoices paid on day 58 into 12 invoices paid on day 8. That is roughly 50 days of cash flow recovered per invoice, 600 days across the year. At a modest 4% cost of capital, the liquidity difference is worth several thousand dollars, without a single renegotiation, legal amendment, or difficult conversation.

The line is one sentence. Write it once, save it as a default on your retainer template, and let the math do the persuading.