Portfolio Rebalancing Calculator
Enter what you hold and what you want to hold. Get the exact dollar trades, plus a no-sell version that rebalances with new cash alone.
Your holdings
Current market value and the weight you want each position to carry.
Contributions, dividends, anything not yet deployed.
Act only when a holding is this far from its target.
Largest drift from target
12.0 pts
Above your 5-point threshold. $105,000 portfolio after new cash.
Total to buy
$17,250
Total to sell
$12,250
May trigger capital gains tax.
Cash left uninvested
$0
Everything is allocated in buy-and-sell mode.
This plan sells $12,250. In a taxable account, check the cost basis before you place those orders. Switching to cash-only mode gets you most of the way there without realising a single gain.
The trades
| Holding | Now | Target | Drift | Trade | After |
|---|---|---|---|---|---|
| US total market (VTI) | $62,000 (62.0%) | $52,500 (50.0%) | +12.0% | Sell $9,500 | $52,500 (50.0%) |
| International (VXUS) | $18,000 (18.0%) | $26,250 (25.0%) | -7.0% | Buy $8,250 | $26,250 (25.0%) |
| Bonds (BND) | $12,000 (12.0%) | $21,000 (20.0%) | -8.0% | Buy $9,000 | $21,000 (20.0%) |
| Individual stocks | $8,000 (8.0%) | $5,250 (5.0%) | +3.0% | Sell $2,750 | $5,250 (5.0%) |
Drift is measured against your current portfolio, before the new cash lands. Everything computes in your browser and nothing is saved, so you can paste in real balances without them leaving the device.
Key takeaways
- Rebalancing means selling what has grown past its target weight and buying what has fallen below it, which mechanically enforces selling high and buying low.
- Drift is the gap between a holding's current weight and its target weight; most disciplined investors act at a 5 percentage point absolute drift rather than on a fixed calendar.
- Rebalancing with new contributions instead of selling avoids realising capital gains entirely, and in a taxable account that is usually worth more than getting the weights exactly right.
- Annual or threshold-based rebalancing captures nearly all the benefit; rebalancing monthly adds trading costs and taxes without improving risk-adjusted returns.
- A portfolio left unrebalanced through a long bull market drifts toward whatever ran hottest, which means its risk rises exactly when valuations are highest.
Frequently asked questions
- How do I calculate portfolio rebalancing trades?
- Add up the total value of the portfolio including any new cash, multiply that total by each holding's target percentage to get its target dollar value, then subtract the current value from the target. A positive result is the amount to buy and a negative result is the amount to sell. This calculator does that arithmetic for every row at once and shows the drift alongside it.
- How often should I rebalance my portfolio?
- Once a year is enough for most people, and threshold rebalancing (acting only when a holding drifts more than about 5 percentage points from its target) is slightly better because it responds to what markets actually did rather than to the calendar. Rebalancing more often than quarterly adds cost and tax drag without a measurable improvement in risk-adjusted return.
- What is cash-only rebalancing?
- Cash-only rebalancing directs new contributions entirely to the underweight holdings and sells nothing. In a taxable account this is usually the right default, because selling an appreciated position to fix a few points of drift can cost more in capital gains tax than the drift costs in risk. The trade-off is that it only closes the gap partially when the new cash is small relative to the portfolio.
- Should I rebalance in a taxable account or a retirement account first?
- Rebalance inside tax-advantaged accounts first, because trades there trigger no tax at all. If your 401(k) or IRA is large enough, you can often fix the whole portfolio's allocation using only those accounts and never touch the taxable one. Treat all your accounts as a single portfolio when you calculate weights.
- Do my target allocations need to add up to 100%?
- Yes. If they do not, the calculator normalises them proportionally so the maths still works, but it will flag the mismatch. A total under 100% usually means you forgot a holding, and a total over 100% usually means a typo in one of the target fields.