This calculator shows how much of a new contribution can be directed toward each part of a portfolio to move it closer to a target allocation without selling existing positions.
Rebalancing Calculator
Use new contributions to move your portfolio closer to target weights without unnecessary selling.
SIMULATOR
Your numbers
Recalculates instantly as you move the sliders.
ESTIMATED RESULT€300
BUY STOCKS€0
BUY BONDS€300
TARGET60%
Buy stocks€0
Buy bonds€300
The new contribution is allocated to move the portfolio toward the target weight without selling positions.
Save my purchase of €300. The new contribution tries to move you toward the target without selling what you already own. Estimated final weight: 69%.
Enter current portfolio value, current allocation, target allocation and new money to contribute. The tool estimates where the contribution would go.
It compares current weights with target weights and allocates new money toward the underweight side until the portfolio gets closer to the desired mix.
In a $20,000 portfolio with an 8% drift, about $1,600 directed to the underweight side helps move the portfolio back toward target.
Rebalancing with contributions is often operationally simpler while accumulating capital, because it avoids selling and can reduce tax or transaction friction.
Common mistakes are rebalancing too frequently, never rebalancing, or selling unnecessarily when new contributions could reduce the drift.
Assumptions: rebalancing is done with new contributions, not by selling. If the contribution is too small, it only partially reduces the drift.
CNMV — Investor Education · Bank of Spain — Financial Education
Rebalancing Calculator, with context
How often should I rebalance?
Some investors use annual or semiannual reviews, or bands such as plus/minus 5 percentage points.
Sell or contribute?
Using new contributions can be more tax-efficient while accumulating.
Does rebalancing improve returns?
Its main role is risk control and keeping allocation close to target, not maximizing return.
What is drift?
The deviation from target allocation after some assets move more than others.
Illustrative results for educational purposes · Educational information, not financial advice.