Wisconsin Post-Judgment Interest Rate: How to Calculate What the Debtor Owes

Your judgment does not stay frozen at the amount the court awarded. Every day the debtor fails to pay, interest accrues — and in Wisconsin, that interest adds up faster than many creditors expect. Understanding the formula, the rate, and how to track partial payments is essential for every enforcement filing you make.

The Formula: Prime Rate Plus One Percent

Wisconsin's post-judgment interest is governed by Wis. Stat. § 815.05(8). The annual rate equals 1% plus the Federal Reserve prime rate in effect when the judgment was entered.

The controlling prime rate depends on when your judgment was entered:

• Judgments entered January 1 through June 30 use the prime rate on January 1 of that year
• Judgments entered July 1 through December 31 use the prime rate on July 1 of that year

Once set, the rate is fixed for the life of that judgment. It does not change if the Federal Reserve adjusts rates later.

The 2026 Rate

The Federal Reserve H.15 prime rate was 6.75% on both January 1, 2026, and July 1, 2026. That means all judgments entered in 2026 accrue interest at 7.75% per annum (6.75% + 1%).

On a $5,000 judgment, that is roughly $1.06 per day. Over a year of non-payment, interest alone adds $387.50 to the balance.

Simple Interest Only

Wisconsin law requires simple interest — no compounding. Interest accrues on the unpaid principal balance from the date of judgment entry until full payment.

Here is the daily calculation:

Daily interest = Principal balance × (Annual rate ÷ 365)

For a $5,000 judgment at 7.75%:

$5,000 × (0.0775 ÷ 365) = $1.06 per day

How Partial Payments Are Applied

When the debtor makes a partial payment, Wisconsin law dictates the allocation order:

1. Accrued interest first — clears all interest accumulated to the payment date
2. Post-judgment costs second — docketing fees, garnishment filing fees, sheriff costs
3. Principal last — whatever remains reduces the original judgment amount

This order matters because it reduces the interest-bearing principal only after interest and costs are cleared. A small payment may not touch the principal at all.

Maintaining a Judgment Ledger

Courts do not track your running balance. WCCA / CCAP shows the original judgment amount, not the current balance with interest and payments. Every time you file for a Writ of Execution or garnishment, state the precise amount owed and verify the ledger by affidavit.

A judgment ledger records every accrual and payment in chronological order. Each entry shows the date, the transaction (interest accrual, partial payment, enforcement cost), and the running balance. Without one, you risk understating or overstating the balance on enforcement filings.

Recoverable Enforcement Costs

You can add statutory collection expenses to the principal balance. These include:

• Docketing fees ($5 per county)
• Transcript of Judgment fees ($14)
• Earnings garnishment filing fees ($121 for small claims, plus $35 e-filing surcharge)
• Sheriff service fees ($33 base plus mileage)
• The $15 garnishee fee tendered with wage garnishments

Private investigation costs and routine postage cannot be added without court approval.

Our Wisconsin judgment collection guide includes a Post-Judgment Interest Calculator Worksheet and a Judgment Balance Tracking Ledger — fillable PDFs that handle the daily accrual math and the payment allocation rules so your filings are always accurate.

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