Portfolio Rebalancing Calculator
Introduction to Portfolio Rebalancing
A portfolio rebalancing calculator turns your current holdings and target mix into a practical trading list. Over time, market moves, dividends, deposits, and withdrawals can push a portfolio away from the balance you planned. By comparing each holding's current dollar value with the allocation you want, this tool shows which positions are overweight, which are underweight, and which can stay put.
Portfolio Rebalancing Formulas Used in This Calculator
The calculator starts by adding the current dollar value of every holding to find the total portfolio size:
where n is the number of holdings you entered.
Next it works out the target dollar amount for each holding from the total portfolio value and the target percentage. If your percentages already add to 100, the math is the familiar percent-of-total calculation; if they do not, the calculator treats them as weights and scales them proportionally before computing trades:
The difference between the target value and current value indicates the amount to buy (if positive) or sell (if negative):
Interpreting Portfolio Rebalancing Results
The result table lists each holding's current value, target value, and suggested action. "Buy" means the current allocation is below target, "Sell" means it is above target, and "Hold" means the difference is small enough that the calculator considers the position effectively on target. The summary beneath the table also calls out the total portfolio value, the combined buy amount, the combined sell amount, and the holding with the largest drift.
Worked Portfolio Rebalancing Example
Imagine a portfolio with three holdings: Stocks at $7,000, Bonds at $2,000, and Cash at $1,000. The target mix is 60% stocks, 30% bonds, and 10% cash, which adds up to a $10,000 portfolio value.
Calculating the target values gives:
- Stocks: $6,000 target
- Bonds: $3,000 target
- Cash: $1,000 target
Stocks are $1,000 above target, Bonds are $1,000 below target, and Cash is already aligned. The calculator therefore recommends selling $1,000 of stocks and buying $1,000 of bonds, while leaving cash unchanged.
If the holdings already matched the target values exactly, the result table would show Hold across the board and the summary would report no drift.
Portfolio Rebalancing Comparison Table
| Holding | Current Value ($) | Target % | Target Value ($) | Trade Amount ($) |
|---|---|---|---|---|
| Stocks | 7,000 | 60 | 6,000 | -1,000 |
| Bonds | 2,000 | 30 | 3,000 | +1,000 |
| Cash | 1,000 | 10 | 1,000 | 0 |
Portfolio Rebalancing Limitations and Assumptions
- The calculator compares dollar amounts and target weights; it does not estimate commissions, bid-ask spreads, taxes, or market impact.
- It does not pick specific tax lots or tell you which shares to sell in a brokerage account.
- The tool uses the target percentages you enter as weights, so the relative mix matters more than the raw total. If they do not add to 100, the calculator rescales them proportionally.
- Market prices can move after you calculate, so re-run the numbers before placing orders.
- This page is a planning aid, not personalized investment advice.
Portfolio Rebalancing Frequently Asked Questions
Why does portfolio rebalancing matter?
Rebalancing keeps one holding from growing too dominant and another from drifting too small, so the portfolio stays closer to the risk mix you intended.
How often should I rebalance a portfolio?
There is no single schedule. Some investors review allocations on a calendar basis, while others wait until a holding drifts far enough from target to justify trading. This calculator helps you measure the gap either way.
Can this calculator handle more than three holdings?
Yes. Add more rows, enter each holding's current value and target percentage, and the calculator will normalize the weights before showing the suggested trade for each line.
Does the calculator include taxes or trading costs?
No. It compares current and target allocation only, so you should review taxes, commissions, and other costs separately if you plan to trade.
What if my target percentages do not add up to 100%?
The calculator rescales them proportionally, so the relative allocation still works. Even so, it is best to enter weights that clearly reflect your intended portfolio mix.
How portfolio rebalancing preserves your risk profile
When a winning holding grows too large, it can make the portfolio riskier than you intended. Rebalancing trims the overweight positions and directs money to the lagging ones, helping you keep the mix close to your plan without having to guess each holding's ideal dollar amount. This calculator uses the entered target percentages to turn that plan into a dollar figure for every row.
Formula for portfolio rebalancing target holdings
The target amount for holding is
, where is the total portfolio value and is the target percentage. The recommended trade is simply , with positive values indicating buys and negative values indicating sells. If your percentages sum to 100, the displayed equation matches the familiar percentage-of-total calculation; if they do not, the calculator scales the mix proportionally before computing the trade list.
Portfolio rebalancing strategy comparison
The table below compares a few common ways investors decide when to rebalance. It is a planning reference rather than an output from the calculator, and it can help you choose whether to rely on calendar reviews, drift bands, or new contributions.
| Trigger | Stocks | Bonds | Cash |
|---|---|---|---|
| 5% drift band | Rebalance a holding once it moves outside the band you set | Keep fixed-income exposure from becoming too large or too small | Use cash as the buffer that absorbs smaller swings |
| Contribution only | Direct new contributions toward the most underweight holding | Let coupon income and new deposits help restore balance | Preserve cash for planned withdrawals or near-term spending |
| Quarterly review | Review the mix every three months and compare it with your target weights | Check whether duration and income still suit your plan | Refill cash after large purchases or withdrawals |
Planning tools that pair with a portfolio rebalance
Use the Asset Allocation Calculator to define or revisit your long-term mix before you trade. If you expect taxable sales, the Capital Gains Tax Calculator can help you estimate the tax side of the move. For retirement accounts, the Safe Withdrawal Rate Calculator can help you think about whether the portfolio still supports your withdrawal plan.
Arcade Mini-Game: Portfolio Rebalancing Practice Run
Use this quick arcade run to practice spotting overweight and underweight positions before you rely on the calculator output.
Start the game, then use your pointer or arrow keys to catch useful allocation signals and avoid bad assumptions.
| Holding | Current ($) | Target ($) | Action |
|---|