Starting a pension at 25 vs 35: what a decade really costs
Two people each save €250 a month at a 6% return until they turn 65. One starts at 25, the other at 35. The early starter pays in €30,000 more over their lifetime — but retires with €246,744 more. The ten-year delay didn’t cost €30,000. It cost a quarter of a million.
The two savers
| Starts at 25 | Starts at 35 | |
|---|---|---|
| Years saving | 40 | 30 |
| Total paid in | €120,000 | €90,000 |
| Interest earned | €377,873 | €161,129 |
| Final pot at 65 | €497,873 | €251,129 |
Both savers put away the same €250 every month, at the same 6% return, compounding monthly. The only difference is when they started. That single variable turns a €30,000 difference in contributions into a €246,744 difference in outcome.
Where the gap comes from
Look at the interest lines in that table. The 25-year-old earns €377,873 in interest on €120,000 paid in — more than three times what they contributed. The 35-year-old earns €161,129 on €90,000 — less than double. Same rate, same discipline, wildly different results.
The reason is time horizon, not talent or amount. Every euro the 25-year-old saves in their first working year sits inside the pension for four decades. It earns a return, and the following year that return earns a return too, and so on for forty years of compound interest. The 35-year-old’s first euro only gets thirty years to do the same job. Money saved late in a decade of delay never gets those extra years back — it simply never compounds over them.
This is why the gap isn’t proportional to the gap in contributions. The early saver contributed 33% more (€120,000 versus €90,000) but ended up with 98% more (€497,873 versus €251,129). The extra decade wasn’t spent adding more money — it was spent letting existing money multiply. That’s the whole mechanism: pensions reward runway more than they reward the size of any single contribution.
The uncomfortable and comforting readings
The uncomfortable reading: a decade not saved is not a decade you can buy back later. No amount of catching up at 45 or 55 recreates what those early compounding years would have done, because there’s no way to insert extra decades before retirement. The cost of delay is locked in the moment the delay happens, even if the saver doesn’t feel it until the pension statement arrives decades later.
The comforting reading: whoever you’re comparing yourself to next, in this exact comparison you are the younger saver. Whatever age you start at, an even earlier start was always theoretically better — but today is still the earliest point left available to you. The 35-year-old in this example did far better than someone who waited until 45. Every year saved sooner than “later” is still compounding for longer than it otherwise would.
Try your own numbers
The pattern holds at any contribution level or start age: the earlier the money goes in, the longer it compounds, and the bigger the share of the final pot that comes from growth rather than contributions. Run your own monthly amount and start age through a compound interest calculator to see your own version of this gap.
Assumptions: €250 monthly contribution, 6% annual return, compounding monthly, no fees, charges, or inflation adjustment applied. Real pension returns vary and are never guaranteed — this is an illustration of compounding mechanics, not a forecast.