qfinbox.tvm.loans

Loan calculations and amortization.

Functions

amortization_schedule(principal, ...[, ...])	Generate loan amortization schedule.
loan_balance(principal, annual_rate, years, ...)	Calculate remaining loan balance after specified payments.
loan_payment(principal, annual_rate, years)	Calculate periodic loan payment.
total_interest_paid(principal, annual_rate, ...)	Calculate total interest paid over the life of the loan.
validate_positive(value[, name])	Validate that a value is positive.

qfinbox.tvm.loans.loan_payment(principal: float, annual_rate: float, years: float, payments_per_year: int = 12) → float

Calculate periodic loan payment.

Parameters:

• principal (float) – Loan principal amount.

• annual_rate (float) – Annual interest rate (as decimal).

• years (float) – Loan term in years.

• payments_per_year (int, default 12) – Number of payments per year.

Returns:

Periodic payment amount.

Return type:

float

Examples

>>> loan_payment(300000, 0.05, 30)
1610.46

qfinbox.tvm.loans.loan_balance(principal: float, annual_rate: float, years: float, payments_made: int, payments_per_year: int = 12) → float

Calculate remaining loan balance after specified payments.

Parameters:

• principal (float) – Original loan principal amount.

• annual_rate (float) – Annual interest rate (as decimal).

• years (float) – Loan term in years.

• payments_made (int) – Number of payments already made.

• payments_per_year (int, default 12) – Number of payments per year.

Returns:

Remaining loan balance.

Return type:

float

Examples

>>> loan_balance(300000, 0.05, 30, 120)
260108.58

qfinbox.tvm.loans.total_interest_paid(principal: float, annual_rate: float, years: float, payments_per_year: int = 12) → float

Calculate total interest paid over the life of the loan.

Parameters:

• principal (float) – Loan principal amount.

• annual_rate (float) – Annual interest rate (as decimal).

• years (float) – Loan term in years.

• payments_per_year (int, default 12) – Number of payments per year.

Returns:

Total interest paid.

Return type:

float

Examples

>>> total_interest_paid(300000, 0.05, 30)
279767.35

qfinbox.tvm.loans.amortization_schedule(principal: float, annual_rate: float, years: float, payments_per_year: int = 12) → DataFrame

Generate loan amortization schedule.

Parameters:

• principal (float) – Loan principal amount.

• annual_rate (float) – Annual interest rate (as decimal).

• years (float) – Loan term in years.

• payments_per_year (int, default 12) – Number of payments per year.

Returns:

Amortization schedule with columns: Payment, Interest, Principal, Balance.

Return type:

pd.DataFrame

Examples

>>> schedule = amortization_schedule(300000, 0.05, 30)
>>> schedule.head()
   Payment  Interest   Principal      Balance
0  1610.46   1250.00     360.46   299639.54
1  1610.46   1248.50     361.96   299277.58