# US Post-Judgment Interest MCP > US Post-Judgment Interest Calculator determines accrued interest on court judgments based on 28 U.S.C. § 1961 and current weekly Treasury Bill rates. This MCP lets your agent calculate total interest owed, find specific historical annual rates, or compare the cost difference if a judgment is paid early versus late. ## Overview - **Category:** finance - **Price:** Free - **Tags:** interest-rate, us-federal-law, treasury-bills, judgment-accrual, financial-calculator ## Description Calculating post-judgment interest for federal court cases isn't simple; it requires tracking variable annual rates against complex statutory rules (28 U.S.C. § 1961). This MCP handles that complexity automatically. Your agent uses the current weekly Treasury Bill data to determine exactly how much interest has built up on a judgment between two dates. You can use this tool to get a total updated balance, check what the annual rate was for any given week, or model out if paying a debt sooner saves money. Connecting through Vinkius gives your agent access to this specialized legal math alongside thousands of other business tools. It's about getting accurate, legally compliant financials without having to manually reference Treasury data and statutes. ## Tools ### interest_accrual_calc Calculates the total interest accrued and provides a new, updated balance for a specific court judgment amount. ### rate_lookup Looks up the official annual interest rate tied to any given date according to federal law. ### interest_scenario_comparison Compares the total accrued interest cost between two different suggested payment dates for a judgment. ## Prompt Examples **Prompt:** ``` How much interest has accrued on a $10,000 judgment from 2024-01-01 to 2024-06-01? ``` **Response:** ``` The total interest accrued on the $10,000 judgment from January 1, 2024, to June 1, 2024, is $150.00, bringing the total balance to $10,150.00. ``` **Prompt:** ``` What was the Treasury Bill rate for 2024-02-15? ``` **Response:** ``` The annual interest rate applicable for the week containing February 15, 2024, was 5.35%. ``` **Prompt:** ``` Compare interest costs for a $5,000 judgment if I pay on 2024-12-01 versus 2025-03-01. ``` **Response:** ``` Choosing to pay on March 1, 2025, instead of December 1, 2024, will result in an additional interest cost of $42.50. ``` ## Capabilities ### Determine total interest owed Calculates the full accumulated interest and provides the updated total balance for a specific court judgment. ### Look up historical annual rates Retrieves the precise annual interest rate applicable to a court date or week. ### Compare payment cost scenarios Models and compares the total interest cost between two different potential payment dates. ## Use Cases ### A judgment was filed six months ago, and the client needs a status update. The paralegal asks their agent: 'What is the current outstanding balance on this $50k judgment?' The agent uses interest_accrual_calc to return the precise total owed, including all accrued statutory interest up to today's date. ### A client needs to decide if they should settle now or wait six months. The billing manager asks their agent to compare payment dates. Using interest_scenario_comparison, the system shows them that delaying payment by half a year adds $X in extra interest costs, making early settlement financially smarter. ### Need to prove what rate was active on a specific day last year. The agent uses rate_lookup to confirm the exact annual Treasury Bill percentage that applied for the week containing 2023-10-15, providing solid documentation for a legal brief. ### Comparing two different settlement offer dates. Instead of manually calculating interest over multiple time gaps, the agent runs both target dates through interest_scenario_comparison and immediately sees the financial penalty/savings associated with each choice. ## Benefits - Get an exact, legally compliant balance. Instead of estimating debt, use interest_accrual_calc to find the precise total owed by tracking federal rates (28 U.S.C. § 1961). - Model payment strategies before you talk to a client. Run two scenarios using interest_scenario_comparison to show them exactly how much money they save by paying early. - Never guess the rate again. The rate_lookup tool pulls the exact annual Treasury Bill rate for any historical date, making your reports accurate every time. - Save hours of cross-referencing statutes and market data. Your agent handles the complex math involving weekly rates automatically, giving you clean results fast. - Maintain legal accuracy. This MCP ensures your calculations adhere strictly to federal law regarding post-judgment interest accrual. ## How It Works The bottom line is you get an accurate, legally compliant calculation of the true debt owed, including all statutory post-judgment interest. 1. You provide your agent with the judgment amount, the original date, and the target calculation period. 2. The MCP first uses current market data to find the applicable annual interest rates for every week within that time frame. This is done via rate lookup. 3. Finally, it aggregates those weekly calculations to deliver a total accrued interest figure and updated balance. ## Frequently Asked Questions **How does the US Post-Judgment Interest Calculator work?** This MCP calculates post-judgment interest according to 28 U.S.C. § 1961 by using current weekly Treasury Bill data, ensuring your figures are legally accurate. **Can I use the rate_lookup tool for future dates?** The rate_lookup is designed to pull historical rates based on actual federal reporting. While it can look up a date, its primary function is verifying past annual rates applicable for specific weeks. **What does interest_scenario_comparison calculate?** It calculates the difference in total interest owed by comparing two different potential payment dates against the same principal judgment amount. This helps you advise on optimal settlement timing. **Does this MCP use state law or federal law?** This MCP is specifically designed for US Federal post-judgment interest calculations mandated by 28 U.S.C. § 1961, so it handles federal statutes only. **What input do I need for interest_accrual_calc?** You must provide the initial judgment amount, the original date of the judgment, and the final payment or calculation date to get an accurate accrual total.