dopecalc

Retirement Calculator

Plan your retirement savings and see if you're on track. Compare your projected savings against your desired retirement income.

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About this Calculator

Plan your retirement savings and see if you're on track. Compare your projected savings against your desired retirement income.

Formula & Calculations

Formula

FV = P(1+r)^n + C[((1+r)^n - 1)/r], Withdrawal = FV × r / (1 - (1+r)^(-w))
Where:
  • FV=Future value of retirement savings at retirement age
  • P=Current retirement savings
  • C=Monthly contribution amount
  • r=Monthly expected rate of return
  • n=Number of months until retirement
  • w=Number of months in retirement (life expectancy minus retirement age)

Assumptions

  • Assumes a constant annual rate of return before and during retirement.
  • Assumes contributions are made at the end of each month.
  • Does not account for Social Security benefits, taxes, or inflation.
  • Withdrawal calculation uses a standard annuity payout formula depleting the balance to zero.

Calculation Examples

Example 1

Inputs:Age: 30, Retire: 65, Life: 90, Savings: $50,000, Monthly: $500, Return: 7%, Desired Income: $60,000/yr
Result:Savings at Retirement: $903,474.82, Monthly Withdrawal: $5,756.61, Annual: $69,079.32, Surplus: $9,079/yr

Starting at 30 with consistent contributions, this person exceeds their retirement income goal with a comfortable surplus.

Example 2

Inputs:Age: 45, Retire: 65, Life: 85, Savings: $100,000, Monthly: $1,000, Return: 6%, Desired Income: $50,000/yr
Result:Savings at Retirement: $558,607.57, Monthly Withdrawal: $3,557.05, Annual: $42,684.60, Shortfall: $7,315/yr

Starting later at 45 means less time for compound growth, resulting in a shortfall of about $7,300 per year. Increasing contributions or retirement age would help.

Example 3

Inputs:Age: 25, Retire: 60, Life: 95, Savings: $10,000, Monthly: $750, Return: 8%, Desired Income: $70,000/yr
Result:Savings at Retirement: $1,562,845.08, Monthly Withdrawal: $11,269.46, Annual: $135,233.52, Surplus: $65,234/yr

Starting early at 25 with 35 years of growth at 8% produces over $1.5 million, far exceeding the desired retirement income.

Frequently Asked Questions

How much do I need to retire?

A common rule of thumb is the 4% rule: you need savings of 25 times your annual expenses to safely withdraw 4% per year adjusted for inflation over a 30-year retirement. However, individual circumstances vary greatly.

What if I'm behind on retirement savings?

If you're behind, focus on increasing your savings rate immediately, consider delaying retirement by a few years, and take advantage of catch-up contributions if you're over 50. Every additional year of saving and compounding makes a significant difference.