Replacement-rate gap (Rentenlücke)
A Rentenlücke (retirement-income gap) is the part of planned retirement spending not covered by reliable retirement income. Calculate it in euros before converting it to a percentage. Use the same tax basis, price date, household scope, and monthly or annual period for every input; otherwise the apparent gap is a unit error.
The core calculation
net retirement spending − reliable net retirement income = retirement-income gap
Reliable income can include expected statutory, occupational, and foreign pensions after estimated deductions. Portfolio withdrawals are usually the funding response to the gap, not reliable income assumed before the plan is tested.
Worked example
A household estimates retirement spending of €3,100 per month in today's purchasing power.
| Item | Net monthly amount |
|---|---|
| Planned spending | €3,100 |
| German statutory pensions | −€1,650 |
| Foreign pension | −€350 |
| Occupational pension | −€250 |
| Monthly gap | €850 |
The annual gap is €850 × 12 = €10,200 in today's euros. If the household compared today's spending with future nominal pension amounts, inflation would distort the result.
Stress-test the number
| Variable | Useful alternative |
|---|---|
| Housing | Rent continues versus mortgage repaid |
| Health and care | Normal costs versus higher care spending |
| Claiming age | Standard age versus earlier or later claim |
| Longevity | Base horizon versus longer life |
| Survivor situation | Two-person versus one-person household |
| Tax and social charges | Gross statements converted to estimated net |
A gap is not evidence that one product is necessary. It is a planning output. Possible responses include later retirement, different spending, higher saving, more work income, occupational provision, or private provision; each has different trade-offs.
Check yourself
Planned net spending is €3,100 monthly and reliable net retirement income is €2,250. What is the monthly gap?
A monthly gap is €850. What is the annual gap?
Which comparison avoids an inflation unit error?
What does a calculated pension gap prove?
Sources
- Deutsche Rentenversicherung — Renteninformation as a cross-pillar planning input, https://www.deutsche-rentenversicherung.de/DRV/DE/Ueber-uns-und-Presse/Presse/Meldungen/2025/250224-renteninformation-hilft-bei-altersvorsorge.html (2025)
- Bundesministerium für Arbeit und Soziales — Cross-pillar retirement information research, https://www.bmas.de/DE/Service/Publikationen/Forschungsberichte/fb527-konzeptionelle-grundlagen-fuer-saeulenuebergreifende-altersvorsorgeinformation.html (accessed 2026)