Glide path calculator — equity allocation by age

Each rule is a pure function of age, evaluated across your whole span and drawn as a line. Subtracting age from 100 is the classic version and from 110 the more aggressive one, both floored at zero and capped at a hundred. The target-date curve follows the shape the large providers use: ninety percent equity while retirement is still forty years away, declining linearly to forty percent at retirement, then easing to a thirty percent floor over the seven years after it. Fixed sixty-forty is drawn as the flat benchmark it is. There is no return and no simulation anywhere in this tool — it compares rules, not outcomes.

An age-based rule treats age as a proxy for everything that actually determines risk capacity: job security, whether there is a defined-benefit pension underneath, how flexible your spending is, and how much of the portfolio you will need in the first five years. Two people the same age can sit far apart on all four. Nothing here models what the bond side actually does, which the 2022 drawdown showed is not the reliable cushion these rules assume.

Why do the rules disagree most near retirement?

Because they encode different answers to one question: whether the risk to manage is running out of money or watching it fall. The subtract-from-age rules keep declining forever and end very conservative, protecting against a fall in the years when you cannot replace losses from income. The target-date shape stops declining, on the view that a retirement lasting thirty years still needs growth and that ending at ten or twenty percent equity is its own risk. Near retirement both concerns are live at once, so the spread is widest there.

Does the bond side of a glide path still work?

Less reliably than these rules assume. Their whole premise is that the non-equity side falls less, and usually by a lot, when equities do. In 2022 that failed: rising rates pushed global bonds down about eighteen percent while equities fell about twenty-seven, so the cushion was thin exactly when it was needed. The loss tolerance page applies both of those drawdowns to each allocation so you can see what it did to a blend.

Should I switch allocation in one move or gradually?

These curves are continuous, but implementing them that way means selling regularly, which costs commission everywhere and realises gains in some countries. Steering new contributions towards the under-weight side moves the allocation in the intended direction without a sale, which is the same mechanism the rebalancing page prices. A glide path is a direction of travel, and it does not need to be tracked to the percentage point.

• Loss tolerance — what each allocation lost in three real crashes
• Rebalancing calculator: what to buy, and what not to sell
• Lazy portfolios: five configurations that need no maintenance