This 401k calculator determines your end balance at retirement, total interest accumulated and the monthly & yearly annuity payment you will receive all adjusted with inflation. Below the tool you can read more about this topic.

Your age today:*
Assumed retirement age:*
Estimated life expectancy:*
Your current 401k balance:
Your own monthly 401k contributions:
Your employer’s monthly 401k contributions:
Estimated annual return on investment:
Average inflation rate:

How does this 401k calculator with inflation work?

This is a personal finance tool that allows you simulate your retirement plan by forecasting the final balance of your 401k account at the retirement age as well as the total earnings in interest and the gross monthly and annually payments you will most likely receive during the pension time, all figures being adjusted with an average inflation if provided.

It takes account of the following data that should be provided:

  • Your age today now plus both the retirement ages and the life expectancy value.

  • Current 401k savings if applicable.

  • Fixed average monthly 401k contribution by your own and by your employer.

  • Constant annual interest rate.

  • Assumed inflation rate (optional).

The algorithm of the 401k calculator applies these equations:

  • No. of years left to contribute during accumulation phase = [A]

[A]= Retirement age – Your age now

  • Final 401k balance = [B]

[B] = CNB*(1+ROI/1200)^( ([A] * 12))+(YMC+EMC)/(ROI/1200)*((1+ROI/1200)^(([A]*12) )-1)


CBN = Your 401k existing balance

ROI = Annual interest rate

YMC = Your personal monthly 401k contribution

EMC = Employer’s monthly 401k participation

ADI = Average inflation rate

  • Total principal added in [A] years = [C]

[C] = CBN + ([A]*12*(YMC+EMC))

  • Total interest earned in [A] years = [D]

[D] = [B] - [C]

  • No. of pension years = [E]

[E] = Life expectancy - Desired retirement age

  • Gross monthly income during retirement = [F]

[F] = [B]/((1-〖(1+(ROI/1200))〗^(-[E]))/(ROI/1200))

  • Gross annual income during retirement = [G]

[G] = [F]*12

  • Inflation adjustment formula

[INFLATION ADJUSTMENT] = [Value]/(1+ADI/100)^[A]

Example of a calculation

In case of a person with these characteristics let's simulate the evolution:

- currently aged 33 with a desired retirement age of 64 and a life expectancy of 88 years;

- has already saved $65,000 in 401K and can afford to pay monthly a contribution of $1,200 (half of it is employer's participantion);

- the interest percentage is 5.88% while the expected inflation figure is 0.9%. This scenario results in:

No. of years left to contribute until retirement = 31.00

Account balance at retirement = $1,664,592.58. In today’s money, this amount adjusted with inflation equals $1,260,903.36.

Total principal saved in 31.00 years = $511,400.00. In today’s money, this equals $387,377.66.

Total interest earned in 31.00 years = $1,153,192.58. In today’s money, this equals $873,525.70.

No. of years of retirement = 24.00

Gross monthly pay out during retirement = $10,798.91. Adjusted with inflation, in today’s money this equals $8,180.01.

Gross annual pay out during retirement = $129,586.98. Adjusted with inflation, in today’s money this equals $98,160.15.

Types of retirement plans

As per today, according to IRS the types of the retirement plans every US citizen may choose from are:

  • Individual Retirement Arrangements (IRAs) and Roth: for 2014 and 2015, your total contributions to all of your traditional and Roth IRAs cannot exceed:

    - $5,500 ($6,500 if you’re aged 50 or older) or;

- your taxable compensation for the year, in case your compensation was less than this amount.

  • 401(k) Plans and 403(b) Plans
  • SIMPLE IRA Plans (Savings Incentive Match Plans for Employees)
  • SEP Plans (Simplified Employee Pension)
  • SARSEP Plans (Salary Reduction Simplified Employee Pension)
  • Payroll Deduction IRAs
  • Profit-Sharing Plans
  • Defined Benefit Plans
  • Money Purchase Plans
  • Employee Stock Ownership Plans (ESOPs)
  • Governmental Plans
  • 457 Plans
  • 409A Nonqualified Deferred Compensation Plans

24 Jan, 2015