Portfolio Rebalancing Calculator
See how far your holdings have drifted from target and exactly what to buy or sell to fix it, with or without selling anything.
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 actually mean?
Bringing each holding back to its intended share of the portfolio after market moves have pushed the weights off target.
Do the target weights need to total 100%?
Yes. If they don't, the calculator flags it - otherwise the buys and sells wouldn't describe a real, complete portfolio.
What does the new-cash-only setting do?
It never sells anything. New cash goes toward whichever holdings are furthest below target, which avoids triggering gains but may not fully close the gap.
Does this include trading costs or tax?
No. Selling can trigger capital gains tax and dealing charges, and both depend on your account type and where you're taxed.
How often should I rebalance?
There's no single right answer. Common approaches are a fixed schedule, or a tolerance band - rebalancing only once a weight drifts more than five points from target.
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