Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Buy (+) or sell (−) stocks
-$12,000.00
Buy (+) or sell (−) bonds
$12,000.00
Add (+) or deploy (−) cash
$0.00
Portfolio total after new money
$100,000
Current stock allocation
72.0%
Drift from target
12.0%
Psst — share this and help Rex grow
One click, a permanent link with your numbers baked in.
How to use this
- 1Enter stocks value ($).
- 2Enter bonds value ($).
- 3Enter cash value ($).
- 4Enter target stocks (%).
- 5Enter target bonds (%).
- 6Enter target cash (%).
- 7Enter new money to add ($).
- 8Read your buy (+) or sell (−) stocks on the right — it updates as you type.
- 9Hit Share to keep the scenario or send it to someone.
About this calculator
Rebalancing forces you to sell what ran and buy what lagged. Doing it with new contributions instead of sales avoids realizing gains in a taxable account.
Worked example
Using the values the calculator loads with:
Inputs
- Stocks value: 72000 $
- Bonds value: 18000 $
- Cash value: 10000 $
- Target stocks: 60 %
- Target bonds: 30 %
- Target cash: 10 %
- New money to add: 0 $
Results
- Buy (+) or sell (−) stocks: -$12,000.00
- Buy (+) or sell (−) bonds: $12,000.00
- Add (+) or deploy (−) cash: $0.00
- Portfolio total after new money: $100,000.00
- Current stock allocation: 72.0%
- Drift from target: 12.0%
What each field means
Inputs
- Stocks value ($)
- The stocks value used in the calculation, measured in $. Starts at 72000 $ so you have a working example on load.
- Bonds value ($)
- The bonds value used in the calculation, measured in $. Starts at 18000 $ so you have a working example on load.
- Cash value ($)
- The cash value used in the calculation, measured in $. Starts at 10000 $ so you have a working example on load.
- Target stocks (%)
- The target stocks used in the calculation, measured in %. Starts at 60 % so you have a working example on load. Accepted range: 0–100 %.
- Target bonds (%)
- The target bonds used in the calculation, measured in %. Starts at 30 % so you have a working example on load. Accepted range: 0–100 %.
- Target cash (%)
- The target cash used in the calculation, measured in %. Starts at 10 % so you have a working example on load. Accepted range: 0–100 %.
- New money to add ($)
- The new money to add used in the calculation, measured in $. Starts at 0 $ so you have a working example on load.
Results
- Buy (+) or sell (−) stocks
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Buy (+) or sell (−) bonds
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Add (+) or deploy (−) cash
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Portfolio total after new money
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Current stock allocation
- Returned as a percentage. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Drift from target
- Returned as a percentage. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the portfolio rebalancing calculator work?
Rebalancing forces you to sell what ran and buy what lagged. Doing it with new contributions instead of sales avoids realizing gains in a taxable account. The underlying maths is: Trade amount = Target % × Total portfolio − Current value of the sleeve.
What do I need to enter?
7 values: stocks value, bonds value, cash value, target stocks, target bonds, target cash, and new money to add. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the buy (+) or sell (−) stocks result mean?
It is returned as a money amount in US dollars and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
Who is this tool for?
It's built for anyone comparing money scenarios before committing — budgeting a payment, sanity-checking a quote, or seeing what a change in rate or term actually costs.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Portfolio Rebalancing Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/portfolio-rebalance
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/portfolio-rebalance" target="_blank" rel="noopener">Portfolio Rebalancing Calculator — RevenueLab</a> (2026).</p>
Source: [Portfolio Rebalancing Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/portfolio-rebalance) (2026).