Portfolio Rebalancing Calculator
Compare your current holdings with your target allocation and see exactly what to buy or sell to get back on target — with or without selling.
Formula and method
Current weight = holding value ÷ total portfolio value. Target value = (total portfolio value + new cash) × target weight.
The action for each holding is target value − current value: a positive figure is a buy, a negative figure is a sell.
In new-cash-only mode no sells are produced; the available cash is allocated across the shortfalls in proportion to their size, and the tool warns if the targets cannot be reached.
Worked example
A €1,000 portfolio holding €600 in A and €400 in B, with a 50/50 target and no new cash.
Target value for each = €500, so the actions are sell €100 of A and buy €100 of B.
With €100 of new cash and selling switched off, the whole €100 goes to B, which narrows but does not close the gap.
FAQ
Frequently asked questions
What does rebalancing mean?
Bringing each holding back to its intended share of the portfolio after market movements have pushed the weights away from target.
Do target weights have to add up to 100%?
Yes. If they do not, the calculator flags it, because the buys and sells would not describe a complete portfolio.
What does the new-cash-only option do?
It never sells. Available cash is directed to the holdings furthest below target, which avoids realising gains but may not fully restore the targets.
Are trading costs and tax included?
No. Selling can trigger capital gains tax and dealing charges, both of which depend on your account type and jurisdiction.
How often should a portfolio be rebalanced?
That is a personal decision. Common approaches are a fixed calendar interval or a tolerance band, such as rebalancing when a weight drifts more than five points from target.
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