Can I build up a pension alongside my employer pension?

Yes, if you have a pension shortfall. You calculate this via your jaarruimte: 30% of your premiegrondslag minus your accrual through your employer (factor A times 6.27).

If you already accrue a lot through work, little room may remain. Where there is room, a lijfrente lets you build extra with a tax advantage. Useful if you want to stop earlier or find your scheme insufficient. Calculate with the jaarruimte calculator.