IRR Calculator (Finance)

irr.py

def calculate_irr(initial_investment, payments):
    min_irr = 0
    max_irr = 0.50
    irr = 0
    while True:
        result = initial_investment
        mid_irr = (min_irr + max_irr) / 2
        for index, payment in enumerate(payments):
            result += payment / ((1 + mid_irr) ** (index + 1))
        if abs(result) < 0.005:
            irr = mid_irr
            break
        if result > 0:
            min_irr = mid_irr
        elif result < 0:
            max_irr = mid_irr
    return irr

def main():
    try:
        initial_investment = -1 * abs(round(float(input("Enter initial investment: ")),2))
        num_payments = int(input("Enter number of payments: "))
        payments = []
        if num_payments <= 0:
            raise "Invalid payments"
        for i in range(num_payments):
            payments.append(round(float(input(f"Enter payment {i+1}:")),2))
        irr = calculate_irr(initial_investment, payments)
        print(f"Your IRR is: {round(irr * 100, 2)}%")
    except:
        print("Invalid input, please try again.")

main()