Portfolio Allocation Calculator

Portfolio allocation and rebalancing calculator

A portfolio allocation calculator helps you answer a practical question: “What percentage of my money is in each asset type right now?” Once you know that, you can compare your current mix to a target mix (for example, 60% stocks, 30% bonds, 10% cash) and estimate what you would need to buy or sell to rebalance. This is useful if your portfolio has drifted over time because one asset grew faster than the others, or if your goals have changed and you want a different risk level.

This calculator is designed to work even if you do not track every detail. If you know your total portfolio value, you can enter it. If you do not, you can leave it blank and just enter the amounts you currently have in each asset bucket. The calculator totals them, calculates your current percentages, and then computes the target amounts based on your target percentages. The difference between the target amount and your current amount is shown as a buy or sell action.

The results are meant for decision making, not perfection. Rebalancing is usually done within accounts you control, and the best approach depends on fees, taxes, and any constraints you have (for example, you may not want to sell a taxable holding today). Still, a clean “buy or sell by bucket” view gives you a starting plan. You can also use this as a contribution guide: if you are adding new money, the “underweight” buckets indicate where new contributions would move you closer to target without selling anything.

Assumptions and how to use this calculator

• Asset buckets are simplified. Your real holdings may not map perfectly to “stocks” or “bonds,” so use the closest fit.
• If your target percentages do not add up to 100%, the calculator can auto-normalize them so the relative intent stays the same.
• Portfolio value is assumed to be the sum of the amounts entered unless you override it with a portfolio value.
• Transaction cost is estimated as a percentage of the total trade value and does not include taxes, spreads, or platform-specific pricing.
• Outputs are a planning estimate. Always consider account rules, minimum trade sizes, and any restrictions on selling or buying.

Common questions

What does “current allocation” mean?

Your current allocation is the percentage split of your portfolio across the buckets you entered. If you have R60,000 in stocks and R40,000 in bonds, your allocation is 60% stocks and 40% bonds. This calculator computes those percentages from your amounts and total portfolio value (either your entered value or the calculated sum).

What if my target percentages do not add up to 100%?

If you tick “Auto-normalize,” the calculator scales your targets so they total 100% while keeping their proportions. Example: if you entered 50% stocks and 30% bonds (total 80%), it will convert them to 62.5% and 37.5% (because 50/80 and 30/80). If you untick auto-normalize, the calculator will require the targets to add up to 100% to avoid ambiguous outputs.

Do I have to sell to rebalance?

No. Selling is only one method. If you are adding new money, you can often rebalance by directing contributions to the underweight buckets until you are close to target. This is usually simpler and may reduce tax impact. Use the “buy” amounts as a guide to where new contributions would be most effective.

Why does my portfolio drift away from target over time?

Because asset classes perform differently. If stocks rise faster than bonds, the stocks portion becomes a larger share of the total even if you did nothing. Rebalancing is the process of bringing that drift back toward a chosen risk profile.

How often should I rebalance?

There is no single correct schedule. Some people rebalance on a calendar (for example quarterly or annually). Others rebalance when drift crosses a threshold (for example, when an asset is 5 percentage points away from target). This calculator helps you quantify the drift and the trade size so you can decide if it is worth acting now.