Portfolio Rebalancing Calculator
Rebalance on drift, not on the calendar.
Work out Portfolio Rebalancing. Rebalance on drift, not on the calendar. Free, with no account and nothing to install.
Recommendation
Rebalance
Largest drift 10.0% against a 5.0 point band
Rebalancing sells what has risen and buys what has fallen, which keeps the portfolio's risk where you set it rather than letting the best-performing asset take it over. It is a risk control, not a return-enhancing strategy, and it usually costs a little return in exchange. The threshold matters more than the schedule. Rebalancing on a fixed calendar trades when nothing has moved; rebalancing on drift trades only when it is worth doing, and the evidence generally favours a band of around five percentage points over quarterly rebalancing. New money is the cheapest way to rebalance. Directing contributions to whatever is underweight avoids selling anything, which avoids both the dealing costs and, outside a tax shelter, the capital gains that come with them.
How the Portfolio Rebalancing Calculator works
What to buy and sell to return a portfolio to its target weights, against a drift band rather than a schedule. New money is applied first, because that is the cheapest way to rebalance.
Also known as: how much should i sell to rebalance · asset allocation drift · when should i rebalance · target allocation calculator
Not financial advice. This calculator is for planning and illustration, not financial advice. Real products carry fees, taxes, and terms it does not model. Confirm figures with your lender or a qualified adviser before committing.
Frequently asked questions
Why rebalance at all?
To keep the portfolio's risk where you set it. Left alone, the best-performing asset grows to dominate, and a 60/40 portfolio quietly becomes an 80/20 one with far more downside than intended.
How often should I rebalance?
On drift rather than on a calendar. A band of around five percentage points trades only when it is worth doing, where quarterly rebalancing trades when nothing has moved and costs money for nothing.
Does rebalancing improve returns?
Usually not — it is a risk control. Selling winners to buy losers costs return in a trending market and adds it in a mean-reverting one. What it reliably does is keep the risk level stable.
What is the cheapest way to rebalance?
New contributions. Directing them at whatever is underweight avoids selling anything, which avoids dealing costs and, outside a tax shelter, the capital gains that come with them.
Should I rebalance inside a taxable account?
Carefully. Selling realises gains, so it is usually better to rebalance inside sheltered accounts and use contributions and dividends to steer the taxable ones.
Put this calculator on your own site
Free to use, on any site, commercial or not. Paste this where you want it to appear. It is a plain iframe, so it works in WordPress, Squarespace, Wix, Webflow, Ghost and anything else that accepts HTML.
<iframe src="https://www.thecalclibrary.com/embed/portfolio-rebalancing-calculator" width="100%" height="640" style="border:1px solid #e2e8f0;border-radius:12px" loading="lazy" title="Portfolio Rebalancing Calculator"></iframe>
<p style="font:13px/1.5 system-ui,sans-serif;margin:6px 0 0;color:#64748b">Powered by <a href="https://www.thecalclibrary.com/portfolio-rebalancing-calculator" style="color:#64748b">Portfolio Rebalancing Calculator</a> from The Calc Library</p>The only condition is that the credit line below the frame stays in place. That one line is what pays for the tool being free — it is how anyone else finds it.