Portfolio Rebalancing Calculator

About this calculator

Portfolio rebalancing is the practice of periodically buying and selling assets to bring your portfolio back to its target asset allocation — most commonly a target stock/bond mix like 60/40 or 80/20 — after market movements have caused it to drift. Because stocks and bonds grow at different rates, a portfolio that starts at 60% stocks can drift to 70% or higher after a strong stock rally, quietly taking on more risk than originally intended.

To rebalance, you enter your current stock and bond dollar values along with your target stock percentage, and the calculation determines exactly how much needs to move from the overweight asset class to the underweight one to restore the target mix — either by selling the overweight asset and buying the underweight one, or by directing new contributions toward whichever side is lagging.

Individual investors, robo-advisors, and financial advisors typically rebalance on a set schedule (annually or quarterly) or when an allocation drifts past a threshold band (often 5 percentage points), since disciplined rebalancing tends to enforce a 'buy low, sell high' habit and keeps portfolio risk aligned with an investor's actual goals and time horizon.