Rebalancing trigger & trade size calculator

In short

Bands, drift and the trade nobody wants to make.

Interactive: rebalancing trigger & trade sizeEasy

Current weight
—
Distance from target
—
Decision
—
Direction
—
Trade size
—
Portfolio value now
—

Note that a large drift moves the weight less than intuition suggests — the risky asset also grows the denominator. Set the drift negative to see the harder version of the discipline: the rule tells you to buy the thing that just fell, which is the moment almost nobody follows their own policy.

The idea behind it

This calculator belongs to Portfolio Practice, where the mechanism it computes is explained step by step, with the formula, what each input means and where the simple model stops being right. Everything is computed in your browser; nothing you type is sent anywhere.

More calculators from Portfolio Practice

All calculators

Information and education only. Every page, figure and calculator on this site exists to explain how financial instruments work. Nothing here is investment, tax or legal advice, a recommendation, or a valuation you can rely on. Full disclaimer