Portfolio Rebalancing Calculator
Over time, your best-performing assets grow to occupy a larger share of your portfolio, shifting you away from your target allocation and quietly raising your risk above the level you chose. Rebalancing restores your original mix by trimming the winners and adding to the laggards — essentially forcing yourself to buy low and sell high. This calculator shows how one year of different returns across asset classes shifts your allocation away from target, then tells you the exact dollar amounts to buy or sell in each asset class to get back to your intended mix. Enter your total portfolio value, your target percentages for stocks, bonds, and cash, and the expected annual return for each asset class, and the calculator projects your new allocation after a year of growth and the buy or sell amounts needed to rebalance. Rebalancing is one of the few free lunches in investing: it controls risk by preventing any single asset class from dominating your portfolio, and over full market cycles it can modestly improve returns by systematically selling what has run up and buying what has fallen. Most experts recommend rebalancing once a year, or whenever any asset class drifts more than 5 percentage points from its target. In taxable accounts, be mindful that selling winners can realize capital gains, so rebalance with new contributions or inside tax-advantaged accounts when possible to avoid triggering unnecessary taxes. The discipline of periodic rebalancing also removes the emotion from investing — instead of guessing when to take profits, you follow a rule that automatically trims your winners and reinforces your laggards at set intervals, which is exactly the behavior that long-term success requires.
Portfolio Rebalancing Calculator
See how your allocation drifts and exactly what to buy or sell to rebalance.
New portfolio value
$109,500
After one year of growth
Stocks now
72%
Sell $1,750
Bonds now
24%
Buy $1,375
Cash now
4.7%
Buy $375
Drift from target
3.2%
Positive rebalance amounts mean buy; negative mean sell. Rebalance once a year (or when any asset drifts more than 5%) to lock in gains and restore your target risk level.
How to Use This Calculator
- 1Enter your total portfolio value.
- 2Set your target percentages for stocks, bonds, and cash.
- 3Enter the expected annual return for each asset class.
- 4Read your new allocation and the buy/sell amounts to rebalance.
Why It Helps
- ✓Reveals how much your allocation has drifted.
- ✓Gives exact dollar buy/sell amounts.
- ✓Encourages disciplined, periodic rebalancing.
- ✓Helps control portfolio risk over time.
About This Calculator
Over time, your best-performing assets grow to occupy a larger share of your portfolio, shifting you away from your target allocation and quietly raising your risk above the level you chose. Rebalancing restores your original mix by trimming the winners and adding to the laggards — essentially forcing yourself to buy low and sell high. This calculator shows how one year of different returns across asset classes shifts your allocation away from target, then tells you the exact dollar amounts to buy or sell in each asset class to get back to your intended mix. Enter your total portfolio value, your target percentages for stocks, bonds, and cash, and the expected annual return for each asset class, and the calculator projects your new allocation after a year of growth and the buy or sell amounts needed to rebalance. Rebalancing is one of the few free lunches in investing: it controls risk by preventing any single asset class from dominating your portfolio, and over full market cycles it can modestly improve returns by systematically selling what has run up and buying what has fallen. Most experts recommend rebalancing once a year, or whenever any asset class drifts more than 5 percentage points from its target. In taxable accounts, be mindful that selling winners can realize capital gains, so rebalance with new contributions or inside tax-advantaged accounts when possible to avoid triggering unnecessary taxes. The discipline of periodic rebalancing also removes the emotion from investing — instead of guessing when to take profits, you follow a rule that automatically trims your winners and reinforces your laggards at set intervals, which is exactly the behavior that long-term success requires.
Disclaimer: This calculator provides estimates for educational purposes only and does not constitute financial, tax, or investment advice. Results depend on assumptions that may not reflect your actual situation.
Frequently Asked Questions
How often should I rebalance?
Most experts recommend rebalancing once a year, or whenever any asset class drifts more than 5 percentage points from its target.
Does rebalancing improve returns?
Its main benefit is risk control — it forces you to buy low and sell high. It may slightly improve returns but primarily keeps your risk level stable.
Will rebalancing trigger taxes?
In taxable accounts, selling winners can create capital gains. Rebalance with new contributions or inside tax-advantaged accounts when possible.
What if my targets don't add to 100%?
The calculator normalizes your targets, but for accurate results your stock, bond, and cash targets should sum to 100%.
Should I rebalance into more than three asset classes?
You can extend the same logic to subclasses (e.g., U.S. vs. international stocks). The principle is identical.
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Written by
James MitchellSenior Financial Analyst & Personal Finance Expert
Certified Financial Planner (CFP) • MBA in Finance, University of Chicago Booth School of Business