Rebalancing Impact Calculator
See what you would need to buy and sell to rebalance your portfolio
Enter your portfolio value and your current and target allocations. The calculator estimates the buy and sell amounts, turnover, and optional costs.
Rebalancing impact calculator for portfolio allocation and buy sell planning
Portfolio rebalancing is the process of moving your investments back toward a target allocation. Over time, markets drift. If one asset class grows faster than the others, your portfolio can become more concentrated than you intended. That can change your risk level and the way your portfolio behaves during market swings. This rebalancing impact calculator helps you translate allocation drift into specific buy and sell amounts.
This calculator is built for two common situations. First, the quick check: you know your portfolio value, your current allocation, and your target allocation, and you want to see what trades you would need to place. Second, the more serious estimate: you also want to approximate the friction of rebalancing, such as transaction costs and possible taxes on sells. It will still produce a result if you skip the optional inputs. When those fields are empty, the calculator assumes zero cost and zero tax.
The main output is a trade plan per asset. For each asset, you will see your estimated current value, target value, and the difference between them. A positive difference means you would buy that amount. A negative difference means you would sell that amount. Alongside that, the calculator estimates total buys, total sells, and portfolio turnover. Turnover matters because it is a simple way to measure how much trading you are doing relative to your portfolio size. Higher turnover usually means higher friction, especially in taxable accounts or when trading costs are meaningful.
Assumptions and how to use this calculator
- If your current allocation percentages do not add up to 100, the calculator normalizes them to 100 based on their relative weights.
- If your target allocation percentages do not add up to 100, the calculator normalizes them to 100 based on their relative weights.
- Transaction cost is applied to the total traded amount (buys plus sells). This is a simplified estimate and may differ from your platform’s actual fee structure.
- Tax on sells is applied as a simple percentage of total sells. This is not a capital gains calculation and does not account for cost basis, exemptions, or holding periods.
- This calculator assumes no new deposits or withdrawals during the rebalance. If you are adding money, your required sells may be lower.
Common questions
What does “buy” and “sell” mean in the results?
“Buy” is the additional amount you would allocate to an asset to reach your target, based on your current portfolio value. “Sell” is the amount you would reduce from an asset to reach the target. The numbers are estimates because real-world execution can be affected by price changes, spreads, and minimum order sizes.
What if my percentages do not add up to 100?
Many people enter rounded percentages or leave out a small asset. This calculator handles that by normalizing the current set and the target set separately. In plain terms, it treats your inputs as relative weights, then scales them to a 100% total. The result is still useful for planning trades.
Do I need to use three assets?
No. If you only have two assets, leave Asset 3 blank or set its allocations to 0. The calculator will still work. If you use three assets, make sure the names and allocations match the way you actually track your portfolio.
How should I pick a transaction cost percentage?
If you do not know, you can leave it blank. If you want a rough estimate, use a small percentage that represents your typical all-in trading friction. This could include platform fees and spreads. The calculator applies the percentage to the total traded amount, so it behaves like a blended estimate.
How accurate is the tax estimate?
It is intentionally simple. Taxes depend on cost basis, realized gains, jurisdiction, account type, and holding period. This calculator uses a flat percentage of total sells to help you think about direction and magnitude. For a precise tax estimate you would need your cost basis and the specific rules that apply to your account.