Calculate savings goals with inflation adjustment

savings-earnings-calculator.py

#!/usr/bin/env python
#
# Calculate savings goals with inflation adjustment.
#

import locale
locale.setlocale(locale.LC_ALL, '')

SAVING_PERIOD = 5           # years

INFLATION_PERCENTAGE = 4    # percentage
UNIT_PRICE = 270            # Australian dollars (AUD)
UNITS_PER_BATCH = 32
RENT_PCM = 1300             # AUD
GOAL_ACCUMULATED = 0        # AUD

rent_pa = RENT_PCM * 12
batch_value = UNITS_PER_BATCH * UNIT_PRICE
SAVINGS_GOAL_PA = 2 * rent_pa   # AUD
saving_goal_total = SAVING_PERIOD * SAVINGS_GOAL_PA

annual_saving_goal_minus_inflation = [int(SAVINGS_GOAL_PA)]
for i in range(0, SAVING_PERIOD):
    inflation = annual_saving_goal_minus_inflation[i] * INFLATION_PERCENTAGE /100
    annual_saving_goal_minus_inflation.append(
        annual_saving_goal_minus_inflation[i] - inflation
    )

inflation_per_annum_list = [SAVINGS_GOAL_PA - n for n in annual_saving_goal_minus_inflation]
expenses_per_annum_list = [0]
real_savings_goal = saving_goal_total + sum(inflation_per_annum_list + expenses_per_annum_list)
real_savings_monthly_goal = real_savings_goal / SAVING_PERIOD / 12
real_savings_annual_goal = real_savings_goal / SAVING_PERIOD
units_sold_per_month = float(real_savings_goal ) / UNIT_PRICE / SAVING_PERIOD / 12
batches_per_annum = float(real_savings_annual_goal) / batch_value

print """
({upb} UNIT) BATCH VALUE:        {bv} @ {up}/unit
SAVING PERIOD:                   {sp} years

Goals:
  ANNUAL SAVING GOAL:            {sgpa}
  TOTAL SAVING GOAL:             {tsg}
  TOTAL INFLATION:               {ti}

  REAL SAVING GOAL:              {rsg}
                  monthly:       {rsmg}
                  annual:        {rsga}

Targets:
  UNITS/month:                   {uspm}
  BATCHES/annum:                 {bpa}

GOAL REMAINING:                  {gr}
""".format(
    upb=UNITS_PER_BATCH,
    bv=locale.currency(batch_value),
    up=locale.currency(UNIT_PRICE),

    sgpa=locale.currency(SAVINGS_GOAL_PA),
    sp=SAVING_PERIOD,
    uspm=units_sold_per_month,

    tsg=locale.currency(saving_goal_total, grouping=True),
    ti=locale.currency(sum(inflation_per_annum_list), grouping=True),
    rsg=locale.currency(real_savings_goal, grouping=True),
    rsmg=locale.currency(real_savings_monthly_goal,  grouping=True),
    rsga=locale.currency(real_savings_annual_goal, grouping=True),
    bpa=batches_per_annum,
    gr=locale.currency(real_savings_goal - GOAL_ACCUMULATED, grouping=True)
)