Washington tool

Washington Unpaid Invoice Demand Calculator

Washington collection statutes give the creditor real tools only when the contract record supports them: reciprocal attorney fees under if any fee clause is on the page, 12 percent statutory default interest under when no other rate is written, and the offer-of-settlement fee shift under Chapter 4.84 RCW on actions of $10,000 or less. This tool estimates the principal balance, statutory interest exposure, fee-shifting posture, documentation strength, and dispute risk so you can decide whether a $575 attorney demand letter is the right first move.

Answer the questions below. The tool estimates the principal balance, 12 percent statutory interest, fee-shifting posture, documentation strength, and dispute risk.

1Principal amount

What is the principal balance owed on the invoice or invoices?

Total invoice amount minus any partial payments. Exclude statutory interest, late fees, and collection costs; the calculator handles those separately.

2Partial payments received

Total partial payments already received against this balance (leave 0 if none).

Used only for interest calculation. The principal amount above should already net of partial payments.

3Invoice due date

When was payment due?

Statutory default interest under RCW 19.52.010 runs from the due date. Today minus the due date gives the days overdue used in the per-diem calculation.

4Written contract

Do you have a signed written contract, master services agreement, or accepted proposal?

Written contracts have a six-year statute of limitations under RCW 4.16.040 and are the foundation for fee recovery under RCW 4.84.330.

5Attorney-fee clause

Does the contract have an attorney-fee clause (any version, even one-sided)?

Per RCW 4.84.330, even a unilateral fee clause in the contract becomes reciprocal by statute. The prevailing party recovers regardless of which side the clause names.

6Interest or late-fee clause

Does the contract specify an interest rate or late fee?

A written rate (up to the RCW 19.52.020 ceiling) overrides the 12 percent statutory default. A late-fee clause supplies recoverable charges under RCW 19.16.250.

7Signed acceptance / purchase order

Do you have a signed purchase order, signed acceptance of the deliverable, or other concrete proof the debtor authorized the work or accepted the goods?

Concrete acceptance evidence converts a soft collection file into a liquidated-debt file. A signed PO or signed deliverable acceptance is the strongest proof.

8Personal guaranty

Is there a personal guaranty (an individual signed to backstop an entity's obligation)?

A personal guaranty reaches individual assets if the entity is judgment-proof. The single most leverage-relevant document on a B2B file.

9Dispute raised

Did the debtor raise a written dispute over scope, quality, or amount before this matter?

A pre-existing written dispute changes the matter from a collection file to a breach-of-contract file. The demand letter has to address the dispute on the merits.

10Debtor type

Is the debtor a business or a consumer?

Consumer debt collected by a third party is subject to the federal FDCPA. B2B debt is governed by the Washington statutes only.

11Own debt or assigned debt

Are you the original creditor, or has this debt been assigned to you or to a collection agency?

Assignees and collection agencies are subject to Chapter 19.16 RCW licensing and to the RCW 19.16.250 limits on charges. Original creditors are subject to RCW 19.16.250 only on what may be charged.

How the score is calculated

The score weighs the elements that drive a Washington unpaid-invoice file to settle. Weights total 100.

The four verdict bands are 80 to 100 (Strong), 60 to 79 (Moderate), 40 to 59 (Weak), and 0 to 39 (Poor).

For background on Washington unpaid-invoice strategy, see the Washington Small Business Collections hub and the Washington Unpaid Invoice Demand Letter resource.