--- title: "Rebalancing calculator" description: "Enter what you hold and your target share per asset class. See what to buy and sell, or how new money closes the gap without selling." canonical: "https://investboard.com/calculators/rebalancing" language: "en" modified: "2026-11-09" author: "Investboard" --- # Rebalancing calculator The amounts that bring your mix back to target. ## What the calculator answers A portfolio set up with a target mix drifts as prices move. If equities rise faster than bonds, the equity share grows, and with it the risk the portfolio carries. The calculator compares your current holdings by asset class with your target shares and shows the amounts that bring the mix back, either by buying and selling or by directing new money only, without selling anything. Choose your money with **Currency** and enter one row per asset class: its current value and its target share. The asset classes are the eight an investment policy uses: equities, bonds, cash, real estate, gold, commodities, crypto and alternatives. The target shares have to add up to 100%. The result shows, for each class, the share it has now, its target share and the amount to buy or sell, and as its headline the total to move. The math is the same in every currency. ## Buy and sell In this mode the total value stays the same, and each class is moved to its target share of that total: ### Change per asset class, buy and sell ```text Total = sum of all current values Change = target share × total − current value A change above zero is a purchase, below zero a sale ``` Because the sales pay for the purchases, all changes together add up to zero. The headline is the sum of the purchases, which equals the sum of the sales: the amount that has to change hands. A portfolio holds 70,000 in equities, 20,000 in bonds and 10,000 in cash, 100,000 in total, against a target of 60% equities, 30% bonds and 10% cash. Equities stand at 70% and bonds at 20%. Selling 10,000 of equities and buying 10,000 of bonds restores the target; cash already sits at 10% and stays as it is. The total to move is 10,000. ## New money only Selling is not always the step an investor wants: it can realize gains and the tax on them, and it adds transaction costs. In this mode nothing is sold. The new amount goes to the classes that sit below their target, measured against the new total: ### Directing new money ```text New total = current total + new money Shortfall = max(0, target share × new total − current value) Purchase = new money × shortfall ÷ sum of all shortfalls ``` If the new money is larger than all shortfalls together, every shortfall is filled and the rest is split by the target shares. The new total is 110,000. At the target, equities would be 66,000, bonds 33,000 and cash 11,000. Equities already hold 70,000 and receive nothing; bonds are 13,000 short and cash 1,000. The 10,000 is split in that proportion: about 9,286 to bonds and about 714 to cash. Afterwards the mix is about 63.6% equities, 26.6% bonds and 9.7% cash: closer to the target, not on it, because no equities were sold. That last point matters when you read the result. With new money only, a large drift can take several contributions to close, and the calculator shows how far one contribution goes. ## What the calculator does not model Tax is not computed. Selling a holding that has risen in value can realize a taxable gain; the result notes this but puts no figure on it, because the tax depends on the purchase price of each holding and on the rules where you are taxed. Transaction costs and spreads are not included either. The amounts are exact figures. Real orders buy whole or fractional units at a price, so the amounts you can actually trade will differ slightly. The calculator works on asset classes, not on individual funds or securities. Which holding within a class to buy or sell is a separate decision, and so is the target itself: the calculator takes your target shares as given and suggests no mix. ## How to read the result The amounts are what restores the target you entered, at the values you entered. They say nothing about whether now is a good moment, and the calculator places nothing: it shows amounts. Many investors follow a fixed rule, either a date in the calendar or a band around each target share, so that rebalancing follows the plan rather than the mood of the market. The two approaches and their tax consequences are compared in [Rebalancing as discipline, not timing](/knowledge/portfolio-rebalancing). A small drift does not always need a trade. Frequent small adjustments carry their own costs, from spreads and fees to tax paid earlier than necessary, as described in [The quiet cost of tinkering](/knowledge/the-quiet-cost-of-tinkering). The new-money mode is one way to move back toward the target without selling. The calculator shows the amounts that restore the target shares you entered. It is not a recommendation to buy or sell any holding, not a suggested allocation and not a tax calculation.