— Stock Market
Portfolio Rebalancing Calculator
Rebalance a drifted portfolio back to target weights. Enter current values and target allocations to see the buys and sells required, or use contribution-only mode to direct new money toward underweight holdings.
Trades to rebalance
$20,000
- Total to buy
- $10,000
- Total to sell
- $10,000
- Portfolio value
- $100,000
Try: Sell & buy back to 60/30/10, With $20k of new money, With a 3% tolerance band, Counting cost & tax
— Trades by asset
| Asset | Current value | Current % | Target % | Buy / sell |
|---|---|---|---|---|
| Equity | $70,000 | 70% | 60% | $-10,000 |
| Debt | $20,000 | 20% | 30% | $10,000 |
| Gold | $10,000 | 10% | 10% | $0 |
— Target allocation
Download— How it works
Target value per asset = total × target weight. Trade = target value − current value (positive = buy, negative = sell). Contribution-only mode directs new money to the under-weight assets in proportion to their shortfall, without selling.
Why and what to trade
When markets move, your allocation drifts: a strong equity run leaves you holding more equity — and more risk — than you intended. Rebalancing sells what’s grown over-weight and buys what’s under-weight to restore the target. The calculator totals your holdings, works out each asset’s target value, and the trade is simply the difference: positive means buy, negative means sell. The trades always net out — what you sell funds what you buy — so a pure rebalance needs no new cash.
Worked example — $100,000 holding $70k equity / $20k debt / $10k gold, target 60/30/10: Equity is $10,000 over (sell), debt is $10,000 under (buy), gold is on target. Sell $10,000 of equity, buy $10,000 of debt — done.
Rebalancing with new money
Selling can trigger transaction costs and — in a taxable account — capital-gains tax, a real drag the calculator estimates. The tax-efficient alternative is cash-flow rebalancing: instead of selling, direct new contributions to the most under-weight assets until the portfolio drifts back into line. Switch to “new money only” mode, enter your contribution, and the calculator splits it across the under-weight assets in proportion to how far each is below target — no sells, no capital-gains tax.
Tolerance bands
Rebalancing on every small wobble racks up costs for little benefit, so many investors use a tolerance band: only rebalance an asset once it has drifted more than, say, 5% from its target. Set a band here and the calculator skips assets still within it, trading only the ones that have breached it. Bands cut trading frequency and cost while keeping risk roughly in check. As always, this is an arithmetic tool on the figures you enter — the tax estimate is a simple rule of thumb, and your actual gains and rates will differ. Not investment advice.
— Reader questions
How do I rebalance my portfolio?
Work out each asset’s target value (total × target weight), then trade the difference from its current value — sell what’s over-weight, buy what’s under-weight. The calculator gives the exact buy/sell per asset.
What is cash-flow rebalancing?
Rebalancing by directing new contributions to under-weight assets instead of selling over-weight ones. It avoids capital-gains tax and transaction costs, which is why it’s often preferred — switch to “new money only” mode to see it.
What is a tolerance band?
A threshold — say 5% — below which you leave an asset alone. You only rebalance holdings that have drifted further than the band from target, cutting trading frequency and cost.
Does rebalancing cost money?
It can: selling may incur transaction fees and, in a taxable account, capital-gains tax. The calculator estimates both so you can weigh them — and shows how rebalancing with new money avoids the tax on sells.
How often should I rebalance?
Common approaches are once a year, or whenever an asset drifts beyond a tolerance band. More frequent rebalancing means more cost for marginal benefit; a band-based or annual schedule is a reasonable middle ground.