@wealthx/borrow-capacity-lib/dist/calculations/borrow-capacity.d.ts

Borrow capacity calculation library for WealthX

import { BorrowCapacityParams, LoanRepaymentParams, HEMCalculationParams, GrossToNetParams, NetToGrossParams } from "../types/calculations.types";
/**
 * Calculate borrowing capacity based on income, expenses, and interest rate
 * Formula based on: https://wealthx.atlassian.net/wiki/spaces/WD/pages/86343838/Finance+Borrow+capacity+formula
 *
 * @param params.monthlyIncome - NET Monthly income not including rental income
 * @param params.monthlyExpense - NET Monthly expense
 * @param params.interestRate - Annual interest rate (as decimal, e.g., 0.05 for 5%)
 * @param params.bufferRate - Buffer of assessment rate (default 0.03)
 * @param params.surplusAvailableForLoanRate - Actual portion of surplus available for loan (default 1.0)
 * @param params.loanTerm - Default 30 years (360 months)
 * @param params.numberOfApplicants - Number of applicants (default 1 for single, 2 for couple)
 * @param params.numberOfDependants - Number of dependants (default 0)
 * @param params.monthlyRentalIncome - NET Monthly rental income
 * @returns Maximum borrowing capacity
 */
export declare function calculateBorrowCapacity(params: BorrowCapacityParams): number;
/**
 * Calculate monthly repayment amount for a loan
 * Formula based on: https://wealthx.atlassian.net/wiki/spaces/WD/pages/86343838/Finance+Borrow+capacity+formula
 *
 * @param params.interestRate - Annual interest rate (as decimal, e.g., 0.05 for 5%)
 * @param params.loanTerm - Loan term in months (default 30 years)
 * @returns Monthly repayment amount
 */
export declare function calculateLoanRepayment(params: LoanRepaymentParams): number;
/**
 * Calculate HEM (Household Expenditure Measure) expense based on income, household composition, and period
 *
 * @param params.totalIncome - GROSS Total household ANNUAL income
 * @param params.numberOfApplicants - Number of applicants (2 for couple, 1 for single)
 * @param params.numberOfDependants - Number of dependants (0-3, capped at 3)
 * @param params.period - Period type (weekly or monthly)
 * @param params.bufferRate - Buffer rate to add on top (default 0.05 for 5%)
 * @returns HEM expense amount
 */
export declare function calculateHEMExpense(params: HEMCalculationParams): number;
/**
 * @param params.grossIncome - Annual gross income
 * @param params.includeMedicareLevy - Whether to include 2% Medicare levy (default: true)
 * @returns Net income after tax and Medicare levy
 */
export declare function grossToNet(params: GrossToNetParams): number;
/**
 * Convert net income to gross income (reverse calculation)
 * @param params.netIncome - Target net income after tax and Medicare levy
 * @param params.includeMedicareLevy - Whether to include 2% Medicare levy (default: true)
 * @returns Gross income required to achieve the target net income
 */
export declare function netToGross(params: NetToGrossParams): number;