Retirement Planning: How Much You Need and How to Get There
Introduction
Retirement is probably the largest and most distant financial goal of your life. Because of that, it is also the easiest to put off. At age 25, it feels like a problem for much later; at 40, something you should get around to soon; at 55, an anxious question sets in: will I have enough?
The answer depends largely on something money cannot buy back: time. The earlier you start planning, the smaller the monthly effort required. This article explains how to estimate how much you will need, how to calculate what to save each month, and what levers you can pull to improve your outcome—no matter when you start.
The best time to plan for retirement was twenty years ago. The second best time is today.
Step 1: Estimate How Much You Will Need
A common benchmark among financial planners is that maintaining a similar standard of living in retirement requires 70% to 80% of your pre-retirement income. Some expenses drop—commuting, raising children, mortgage payments if your home is paid off—while others rise, especially healthcare.
Still, the best estimate is your own: picture what your retired life will look like and calculate what it would cost per month—housing, food, healthcare, transportation, leisure, and family support.
Step 2: Subtract What Is Already Covered
Many pension systems provide a public pension, a mandatory contribution-based pension, or both. Before calculating how much extra you need to save on your own, estimate what your mandatory system will pay out. Most pension agencies and providers offer online calculators that project your future benefit based on your age, current balance, and expected future contributions.
The gap between what you will need each month and what the mandatory system will provide is what you must cover with personal savings.
Step 3: Turn That Monthly Gap into a Target Nest Egg
How much capital do you need to cover a monthly income gap? A well-known benchmark is the 4% rule, derived from William Bengen's 1994 research and the Trinity Study: withdrawing 4% of your initial portfolio in the first year of retirement, and adjusting that dollar amount for inflation each year thereafter, historically allowed a diversified U.S. portfolio to last at least thirty years.
Stated the other way around: your target nest egg is roughly 25 times the annual spending you need to cover. If your monthly gap is $1,000—or $12,000 a year—your target capital is around $300,000.
This is a rule of thumb based on historical data from one country, not an ironclad guarantee. Still, it serves as a very useful starting point.
Step 4: Calculate Your Monthly Savings
This is where time becomes decisive. Assuming a 4% real annual return (after inflation), accumulating $300,000 requires saving approximately:
- Over 40 years: about $254 per month.
- Over 30 years: about $432 per month.
- Over 20 years: about $818 per month.
Starting ten years earlier cuts the required monthly effort nearly in half. Starting twenty years earlier cuts it to less than a third.
Levers You Can Pull
If the math points to a monthly figure that feels out of reach right now, several levers can close the distance:
1. Start earlier or save more. The most direct lever. 2. Use tax-advantaged accounts and employer matching. Many countries offer voluntary retirement savings plans with tax benefits—such as APV in Chile, or 401(k)/IRA plans in the US—or employer matching contributions. Leaving an employer match untouched is leaving free money on the table. 3. Cut investment fees. A one-percentage-point difference in annual management fees can eat up a massive share of your final nest egg over several decades. 4. Match your asset allocation to your age. Hold more equities when retirement is decades away, and shift gradually toward stability as the date approaches. 5. Work a few extra years or transition to part-time work. Each additional year adds contributions, gives your portfolio more time to compound, and reduces the number of retirement years your savings must fund. 6. Retire debt-free. Entering retirement with a paid-off home dramatically lowers your required monthly income.
Key Risks to Keep in Mind
- Longevity risk: outliving your projections. Planning up to age 90 or 95 is prudent.
- Inflation: erodes purchasing power over a twenty- or thirty-year retirement.
- Healthcare: medical and long-term care costs tend to rise with age.
- Sequence-of-returns risk: a severe market crash right at the start of retirement causes far more lasting damage than a crash ten years later. That is why reducing portfolio risk gradually as you approach retirement is so important.
Common Mistakes
Putting off retirement savings until you have "extra money left over."
Relying solely on mandatory pensions without checking what they will actually pay.
Withdrawing retirement funds early for everyday spending. It solves today's cash crunch at the expense of your future self.
Ignoring management fees on pension and investment funds.
Taking on too much investment risk right before retirement—or, conversely, investing too conservatively when you still have decades ahead of you.
Conclusion
Retirement planning comes down to four steps: estimate how much monthly income you will need, subtract what your pension system will cover, multiply the annual gap by 25 to find your target nest egg, and calculate the monthly savings needed to reach it. Time is the most powerful variable in the equation, so every year counts. This week, use your country's official pension simulator to estimate your future benefit, calculate the gap against what you would need, and set up an automatic voluntary contribution—even a small one—to start closing it.
References
- Bengen, W. P. (1994). Determining withdrawal rates using historical data. Journal of Financial Planning, 7(4), 171-180.
- Cooley, P. L., Hubbard, C. M., & Walz, D. T. (1998). Retirement savings: Choosing a withdrawal rate that is sustainable. AAII Journal, 20(2), 16-21.
- OECD (2023). Pensions at a Glance 2023: OECD and G20 Indicators. OECD Publishing.
- Pfau, W. D. (2017). How Much Can I Spend in Retirement? A Guide to Investment-Based Retirement Income Strategies. Retirement Researcher Media.