How to plan your retirement
Why it pays to start early, how much you need and how to build your complement to the public pension.
Retirement seems far away until it is not. The good news is that, thanks to compound interest, you do not need to contribute huge amounts: you need to start early and be consistent. This guide sums up how to lay out your retirement plan step by step.
Why start as early as possible
Time is the decisive ingredient. Someone who starts contributing at 30 can reach retirement with double the capital or more than someone who starts at 40, even if both contribute the same each month. The reason is compound interest: each extra year multiplies the effect. If you are running late, do not be discouraged; you will simply have to contribute more and keep the discipline.
Before putting a single euro towards retirement, secure the basics: an emergency fund covering 3 to 6 months of expenses and no expensive debt (credit cards, consumer loans). Investing long-term while paying 15% interest on debt is losing money with extra steps.
How much you need: the 4% rule
A quick way to estimate your goal is to multiply by 25 the annual expenses you expect in retirement (it is the flip side of the 4% rule). If you estimate spending €20,000 a year, you would need about €500,000 of capital, assuming you could withdraw 4% per year adjusted for inflation with a low chance of running out in 30 years. It is an indicative reference, not a certainty. Work out your figure in the retirement calculator.
A concrete example
Contributing €300 a month from age 35 to 67 with an average 5% return would accumulate around €277,000. Of that figure, only about €115,000 would be your contributions; the rest is added by compound interest. That capital, spread over a 20-year retirement, is about €1,150 a month to complement your public pension.
How much to contribute per month depending on when you start
Let's set the same goal for three people: reaching 67 with €240,000 (which under the 4% rule would provide about €800 a month). With an average return of 5% a year, the required monthly contribution changes enormously depending on the age they start:
| You start at | Years contributing | Monthly contribution needed |
|---|---|---|
| Age 25 | 42 | ≈ €140 a month |
| Age 35 | 32 | ≈ €255 a month |
| Age 45 | 22 | ≈ €500 a month |
The figures are rounded and assume a constant contribution and a uniform return, which is not how reality works (markets go up and down). But the order of magnitude is what matters: starting ten years earlier cuts the monthly effort almost in half. Check your own case with your own numbers in the retirement calculator.
What vehicles you can use
- Pension plans: often offer tax advantages on contributions, but are taxed on withdrawal and have limited liquidity until retirement.
- Index funds and ETFs: more flexibility and low fees, ideal for the long term. You can withdraw whenever you want (paying tax on the gains).
- A combination of both: many savers use the pension plan for the tax advantage and complement it with index funds for flexibility.
Do not forget the public pension or inflation
Your total income at retirement will be the sum of your private savings and the public pension you are entitled to. It is wise to check your estimated pension and not rely only on it, because the replacement rate (pension relative to your last salary) tends to fall. And remember to always reason in real terms: with inflation of 2-3%, money 30 years from now buys considerably less than today. You can see it in the inflation calculator.
In Spain you can check your estimated pension in the official Social Security simulator, on its online portal. Treat it as a snapshot of today, not a promise: the calculation rules change and, the further you are from retiring, the wiser it is to treat that figure as a complement rather than the foundation of your plan.
Mistakes to avoid
- Putting it off "until next year". Each year lost is hard to recover.
- Relying only on the public pension. A private complement reduces uncertainty.
- Not reviewing the plan. Income, expenses and goals change; review your contributions from time to time.
A plan to get started this week
- Work out your target. Estimate your annual expenses as a retiree, multiply them by 25 and subtract whatever your estimated pension covers. That's the figure your savings need to provide.
- Turn the target into a monthly contribution. Use the retirement calculator with a prudent return (4-5%) and adjust until you land on an amount you can sustain.
- Pick the vehicle and automate. Open the pension plan or index fund and schedule an automatic transfer for the day after payday. If it depends on your willpower every month, it will fail.
- Review once a year. Raise the contribution when your salary goes up and check you're still on track. A yearly review is enough; checking every week only adds anxiety.
Frequently asked questions
Pension plan or index fund?
It depends on your marginal income-tax rate and how much you value liquidity. A pension plan defers taxes today (attractive at high rates) in exchange for illiquidity and the whole withdrawal being taxed as work income. An index fund stays liquid and you only pay tax on gains when you sell. Many savers combine both; for specific doubts, check with a tax advisor.
How much money do I need to retire?
The quick reference is 25 times your annual expenses (the 4% rule), after subtracting whatever the state pension covers. Someone spending €24,000 a year with an estimated pension of €15,600 would need to cover €8,400 a year: about €210,000 of capital. It's a reasonable planning approximation, not a guarantee.
What if I start late, at 50?
It's still worth it, but the main lever stops being the return and becomes your savings rate and your actual retirement age. From 50 to 67 there are 17 years: contributing €500 a month at 5% you'd gather around €160,000. Retiring two or three years later, or trimming your expected expenses, moves the needle more than chasing aggressive returns.
Should I discount inflation in the numbers?
Yes, always. The simplest way is to reason in today's euros: use a real return (the expected return minus inflation, e.g. 5% − 2% = 3%) and the result will already be in current purchasing power. The inflation calculator shows how much 2-3% inflation eats away over 20 or 30 years.
Once you have your goal, simulate different scenarios in the retirement calculator and reinforce concepts with the compound interest guide and the guide on how to start investing.
