What is portfolio rebalancing?

Rebalancing brings your portfolio back to its target mix of asset types after market movements have shifted it. It keeps your risk level in line with your plan rather than letting a strong run push you into more risk than intended.

How often should I rebalance?

Common approaches are once a year or when an allocation drifts beyond a set band. Rebalancing with new contributions, by directing them to the underweight asset, can avoid selling and any tax on gains.

Should I sell to rebalance?

You can rebalance by selling the overweight asset and buying the underweight one, or more gently by directing new contributions to the underweight asset until the mix is restored.

Portfolio Rebalancing Calculator

This New Zealand calculator helps investors rebalance a portfolio back to its target mix of growth and income assets, a discipline that keeps risk in check as markets move. You enter your current holdings and your target allocation, and the tool calculates exactly how much to buy or sell of each to return to your intended balance, including the option to rebalance using new contributions rather than selling. The breakdown shows your current versus target weightings and the specific adjustments needed, helping investors avoid letting a portfolio drift into more risk than they intended after a strong run, and apply a simple, proven approach to managing their investments.

Current growth assets

Current income assets

Target growth allocation

New contribution available (optional)

to return to your target allocation

Current growth weight0%

Target growth0%

Contribution plan-

Selling to rebalance can trigger tax on gains for some investors, so rebalancing with new contributions, directed to the underweight asset, is often gentler. The growth and income split is your risk dial; rebalancing keeps it where you intend. Estimate only, not financial advice.

How it works

The calculator adds your growth and income assets to find your total, then compares your current growth weighting with your target. If growth has drifted above target, you are carrying more risk than planned and would sell some growth or buy income to rebalance; if below, the reverse. If you enter a new contribution, it shows how much of that to direct to the underweight asset, which rebalances without selling and any tax on gains.

Worked example

With $70,000 growth and $30,000 income, growth is 70% of a $100,000 portfolio. Against a 60% target, growth is $10,000 overweight, so you would move $10,000 from growth to income, or direct new contributions to income until the mix is back to 60 and 40.

Related calculators

Investment Calculator: project investments.
Net Worth Calculator: your total position.
Compound Interest Calculator: growth over time.
Risk and Return guide: risk basics.

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