Legal Fee & Interest Calculation Engine

In legal technology and judicial case management, financial calculations demand strict mathematical precision and legal certainty:

Court Filing Fees: Calculated using progressive tiered brackets based on statutory judicial fee schedules, tolerating zero floating-point error;
Asset Preservation Fees: Tiered by preservation target amounts with a mandatory statutory ceiling of 5,000 RMB;
Delayed Performance Interest: Calculated via compound or benchmark daily interest rates (such as 0.0175% daily) with calendar date precision.

BitzOrcas.Platform.LegalCalculators is a zero-database-dependency, deterministic domain algorithm library engineered for sub-millisecond execution.

1. Tiered Court Filing Fee Algorithm

Calculations utilize C# high-precision decimal values to prevent binary floating-point rounding errors:

using System;

namespace BitzOrcas.Platform.LegalCalculators;

/// <summary>
/// Result record containing court filing fee calculations
/// </summary>
public sealed record LitigationFeeCalculationResult(
    decimal ClaimAmount,
    decimal StandardCourtFee,
    decimal SummaryProcedureFee,
    decimal ConciliationFee
);

/// <summary>
/// Deterministic court litigation fee calculator
/// </summary>
public static class CourtLitigationFeeCalculator
{
    /// <summary>
    /// Calculates standard first-instance court fees based on monetary claim amounts
    /// </summary>
    /// <param name="claimAmount">Total claim amount in standard currency</param>
    /// <returns>Calculation result including full, summary, and conciliation amounts</returns>
    public static LitigationFeeCalculationResult CalculatePropertyCaseFee(decimal claimAmount)
    {
        if (claimAmount <= 0)
        {
            return new LitigationFeeCalculationResult(0, 0, 0, 0);
        }

        decimal fee = 0;

        // Tier 1: Up to 10,000 RMB: 50 RMB flat
        if (claimAmount <= 10000m)
        {
            fee = 50m;
        }
        // Tier 2: 10,000 to 100,000 RMB: 2.5%
        else if (claimAmount <= 100000m)
        {
            fee = 50m + (claimAmount - 10000m) * 0.025m;
        }
        // Tier 3: 100,000 to 200,000 RMB: 2%
        else if (claimAmount <= 200000m)
        {
            fee = 50m + 90000m * 0.025m + (claimAmount - 100000m) * 0.02m;
        }
        // Tier 4: 200,000 to 500,000 RMB: 1.5%
        else if (claimAmount <= 500000m)
        {
            fee = 50m + 90000m * 0.025m + 100000m * 0.02m + (claimAmount - 200000m) * 0.015m;
        }
        // Tier 5: 500,000 to 1,000,000 RMB: 1%
        else if (claimAmount <= 1000000m)
        {
            fee = 50m + 90000m * 0.025m + 100000m * 0.02m + 300000m * 0.015m + (claimAmount - 500000m) * 0.01m;
        }
        // Tier 6: 1,000,000 to 2,000,000 RMB: 0.9%
        else if (claimAmount <= 2000000m)
        {
            fee = 50m + 90000m * 0.025m + 100000m * 0.02m + 300000m * 0.015m + 500000m * 0.01m + (claimAmount - 1000000m) * 0.009m;
        }
        // Tier 7: 2,000,000 to 5,000,000 RMB: 0.8%
        else if (claimAmount <= 5000000m)
        {
            fee = 50m + 90000m * 0.025m + 100000m * 0.02m + 300000m * 0.015m + 500000m * 0.01m + 1000000m * 0.009m + (claimAmount - 2000000m) * 0.008m;
        }
        // Tier 8: 5,000,000 to 10,000,000 RMB: 0.7%
        else if (claimAmount <= 10000000m)
        {
            fee = 50m + 90000m * 0.025m + 100000m * 0.02m + 300000m * 0.015m + 500000m * 0.01m + 1000000m * 0.009m + 3000000m * 0.008m + (claimAmount - 5000000m) * 0.007m;
        }
        // Tier 9: 10,000,000 to 20,000,000 RMB: 0.6%
        else if (claimAmount <= 20000000m)
        {
            fee = 50m + 90000m * 0.025m + 100000m * 0.02m + 300000m * 0.015m + 500000m * 0.01m + 1000000m * 0.009m + 3000000m * 0.008m + 5000000m * 0.007m + (claimAmount - 10000000m) * 0.006m;
        }
        // Tier 10: Over 20,000,000 RMB: 0.5%
        else
        {
            fee = 50m + 90000m * 0.025m + 100000m * 0.02m + 300000m * 0.015m + 500000m * 0.01m + 1000000m * 0.009m + 3000000m * 0.008m + 5000000m * 0.007m + 10000000m * 0.006m + (claimAmount - 20000000m) * 0.005m;
        }

        var standardFee = Math.Round(fee, 2, MidpointRounding.AwayFromZero);
        var halfFee = Math.Round(standardFee / 2m, 2, MidpointRounding.AwayFromZero);

        return new LitigationFeeCalculationResult(
            ClaimAmount: claimAmount,
            StandardCourtFee: standardFee,
            SummaryProcedureFee: halfFee,
            ConciliationFee: halfFee
        );
    }
}

2. Asset Preservation Fee Algorithm (5,000 RMB Ceiling)

Asset preservation follows tiered brackets capped strictly at 5,000 RMB:

Up to 1,000 RMB: 30 RMB;
1,000 to 100,000 RMB: 1%;
Over 100,000 RMB: 0.5%;
Absolute maximum cap: 5,000 RMB.

public static decimal CalculatePreservationFee(decimal preservationAmount)
{
    if (preservationAmount <= 0) return 0m;
    if (preservationAmount <= 1000m) return 30m;

    decimal fee;
    if (preservationAmount <= 100000m)
    {
        fee = 30m + (preservationAmount - 1000m) * 0.01m;
    }
    else
    {
        fee = 30m + 99000m * 0.01m + (preservationAmount - 100000m) * 0.005m;
    }

    // Enforce 5,000 RMB statutory ceiling
    return Math.Min(Math.Round(fee, 2, MidpointRounding.AwayFromZero), 5000m);
}

3. Delayed Performance Penalty Interest Engine

Calculates statutory delayed judgment execution penalty interest:

Statutory Delayed Performance Penalty Formula: Delayed Interest = Unsatisfied Principal × Daily Statutory Rate (0.0175%) × Elapsed Days

public static decimal CalculateDelayedPerformanceInterest(
    decimal principalAmount,
    DateOnly startDate,
    DateOnly endDate)
{
    if (principalAmount <= 0 || endDate <= startDate)
    {
        return 0m;
    }

    var days = endDate.DayNumber - startDate.DayNumber;
    const decimal dailyRate = 0.000175m; // 0.0175% daily statutory rate

    var interest = principalAmount * dailyRate * days;
    return Math.Round(interest, 2, MidpointRounding.AwayFromZero);
}

Connectors: Legal Connectors & Judicial Cloud Integration
Time Tracking: Immutable Timekeeping & Audit Trails
ADR Reference: ADR 0102: Native AOT as Design Constraint

Legal Fee & Interest Calculation Engine

1. Tiered Court Filing Fee Algorithm

2. Asset Preservation Fee Algorithm (5,000 RMB Ceiling)

3. Delayed Performance Penalty Interest Engine

4. Related Architecture Decisions & Deep Dives