hecs-repayment-years.py

# -*- coding: utf-8 -*-
"""
Created on Sat May 31 11:35:04 2014

@author: freespace
"""

def repayment_pc(earning):
    thresholds = [   [59421, 0.04],
                    [65497, 0.045],
                    [68939, 0.05],
                    [74105, 0.055],
                    [80257, 0.06],
                    [84481, 0.065],
                    [92970, 0.07],
                    [99069, 0.075],
                ]
    for upperthres, pc in thresholds:
        if earning < upperthres:
            return pc
    # this is the max repayment rate
    return 0.08
    
debt=50e3
interest = 0.06
earning = 60e3
max_earning = 65e3
yearly_raise = 0.03
years = 0
max_years= 100

while debt > 0:
    payment = repayment_pc(earning) * earning 
    debt -= payment
    debt *= (1+interest)
    earning *= (1+yearly_raise)
    earning = min(earning, max_earning)
    years += 1
    print years, debt, interest, earning, payment
    
    if years > max_years:
        break