Should I charge interest on a payment plan?

You can, and it is reasonable to include an interest rate on the outstanding balance — especially if the invoice is significantly overdue. Make sure any interest provision is disclosed clearly in your written agreement. Typical rates are 1 to 1.5 percent per month, though state usury laws may cap this.

What is a promissory note and do I need one?

A promissory note is a written promise to pay a specific amount under specific terms. It is legally enforceable and simplifies the process of obtaining a court judgment if the client defaults. For amounts over $1,000 to $2,000, it is worth using. For smaller amounts, a written email confirmation of the terms is usually sufficient.

What if the client refuses a payment plan?

If they refuse a plan and cannot pay the full amount, you are at an impasse. Your next steps are a formal demand letter, small claims court (for eligible amounts), or a collections agency. Document the refusal in writing — it supports your case if you pursue legal action.

Can I cancel the payment plan if the client misses a payment?

Yes, and your written agreement should say so explicitly. A standard clause states that if any installment is more than 5 business days late, the full remaining balance becomes immediately due. This clause gives you legal footing to pursue the whole amount if the plan breaks down.

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May 7, 2026 · 6 min read

How to Set Up a Payment Plan for Overdue Invoices

Payment plans turn stalled overdue invoices into a recovery path. Here is how to structure one, what to put in writing, and what to do if the client misses a payment.

A payment plan for an overdue invoice is an agreement to accept payment in installments rather than as a lump sum. From a cash flow perspective, installments are inferior to full payment — but a payment plan you actually collect is almost always better than a lump sum you never see. Payment plans work best when the client is financially strained but willing to pay, when the invoice is large relative to the client's typical cash flow, and when you have an established relationship worth preserving. Offering a plan too early in the follow-up process can signal that you do not expect payment on the original terms; used at the right moment, it unlocks resolution from a stalled situation.

The structure of a good payment plan starts with a non-trivial deposit at the time of agreement — typically 20 to 30 percent of the balance. This deposit signals commitment, recovers some cash immediately, and raises the cost of simply walking away from the arrangement. The remaining balance should be split into installments of equal or decreasing size over a period that matches the client's ability to pay, with a clear due date for each. Monthly installments are the most common structure; weekly installments work for smaller amounts or shorter timelines. Every installment date should be a hard date, not a vague range.

Whatever you agree to verbally must be confirmed in writing before the first installment is due. A simple email summary is the minimum: it should state the original invoice number and balance, the agreed installment amounts and dates, and what happens if a payment is missed. For larger amounts — generally anything over $1,000 to $2,000 — a promissory note or formal payment agreement adds meaningful legal weight. A promissory note is a written promise to pay a specific amount under specific terms; it is admissible in court and simplifies judgment if the client defaults. Templates are widely available and generally do not require an attorney for straightforward arrangements.

Automate the payment if possible. Getting the client to set up recurring ACH transfers or authorizing you to charge a credit card on each installment date removes friction and eliminates the risk of them simply forgetting. If they resist automated payment, at a minimum confirm each installment via a calendar invite or email reminder a few days before the due date. Passive plans — where neither party takes action until a payment is missed — fail more often than active plans with clear triggers.

If a client misses an installment, contact them the same business day. Reference the payment plan agreement specifically: 'We agreed on [date] that the payment of [amount] was due today, and I have not seen it arrive.' Give them 24 to 48 hours to remedy it before escalating. A single missed payment with a prompt cure is often a genuine oversight. A pattern of missed payments means the plan is not working and you need to either renegotiate or escalate to a demand letter and potential legal action. The plan exists to collect money, not to extend the collection timeline indefinitely.

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