Core Satellite Allocation Calculator
Convert core and relative satellite weights into portfolio percentages, with a clearly labeled illustrative concentration alert.
How it works
Enter each core holding as a percentage of the whole portfolio. The sum of core weights sets the core allocation. The remaining percentage is the satellite sleeve.
Enter a relative weight for each satellite. The calculator divides each weight by the sum of satellite weights, then applies that share to the remaining sleeve. For example, weights of 25 and 75 split the sleeve into 25% and 75%.
Review the effective portfolio percentages and any illustrative concentration alerts. Repeated tickers within the same sleeve are combined before the satellite alert is checked.
Use the output to inspect the arithmetic of an allocation you specify. It does not evaluate fund holdings, market prices, risk, taxes, or whether an allocation fits your circumstances.
Step by step
- Enter core holdings as portfolio percentages
- Enter satellite weights relative to their sleeve
- Review portfolio percentages and illustrative alerts
Worked example
Set core holdings to VTI at 80%. Set AAPL and NVDA satellite weights to 25 and 75. The remaining 20% sleeve is split into 5% AAPL and 15% NVDA.
The results show VTI at 80%, AAPL at 5%, and NVDA at 15%. Only NVDA triggers the illustrative alert because its portfolio weight is greater than 5%. The threshold is not an investment recommendation.
When to use this calculator
Use this calculator to convert a proposed core allocation and relative satellite weights into portfolio percentages.
Use a separate holdings or market data tool when you need to examine fund overlap, current values, or portfolio risk.
Common mistakes
Do not enter satellite weights as whole portfolio percentages. They are relative shares of the satellite sleeve. Check that core weights use whole portfolio percentages and that each positive weight has a ticker.
Do not treat the 5% alert as a suitability test or risk estimate. The calculator does not inspect security holdings or market data, so similar exposures are not detected. A ticker entered in both sleeves is shown separately in each sleeve.
The Formula
Satellite Share = Satellite Weight / Sum of Satellite Weights
Effective Satellite % = Satellite Share × (100% − Core %)
Core weights are percentages of the whole portfolio. Satellite weights are relative to one another and are normalized within the remaining sleeve. Duplicate tickers within a sleeve are combined. The same ticker entered in both sleeves remains in separate rows. With no positive satellite weights, the remaining sleeve is shown as unassigned capacity, not as cash. A warning appears only when the displayed satellite percentage rounded to two decimals is greater than 5%. The calculation does not measure overlap, correlation, performance, or suitability.
Limitations and assumptions
This is an allocation arithmetic example, not investment advice. It does not look up tickers, prices, fund holdings, overlap, correlation, returns, taxes, or risk. The alert above a displayed 5% is illustrative and is not a recommended limit. Core holdings can total less than 100%, leaving the rest as the satellite sleeve. If no positive satellite weights are entered, that sleeve remains unassigned and is not labeled as cash. Duplicate tickers across core and satellite sleeves remain separate, so their combined exposure is not shown. Percentages are rounded to two decimals, so displayed rows can differ from a total by one hundredth of a percentage point.
Key terms
- Core allocation
- Core holdings receive the portfolio percentages entered directly. The remaining percentage is the satellite sleeve.
- Relative satellite weight
- A satellite weight describes its share relative to the other satellite weights, not a whole portfolio percentage.
- Concentration alert
- The calculator flags a satellite only when its displayed portfolio percentage, rounded to two decimals, is greater than the illustrative 5% threshold.
Compare alternatives
Compare portfolio weights here, then use Portfolio Rebalancer to compare a target mix with current holdings or ETF Overlap Detector to inspect shared holdings.
This calculator converts relative satellite weights into portfolio percentages. It does not retrieve fund holdings, calculate overlap, measure risk, or recommend an allocation.
FAQ
What is core satellite investing?
A core satellite allocation places a defined portfolio share in core holdings and assigns the remaining share to satellite holdings. This calculator translates those inputs into portfolio percentages.
How do I structure inputs?
Enter core weights as percentages of the whole portfolio. Enter satellite weights as relative shares of the satellite sleeve. The calculator normalizes satellite weights, so they do not need to add to 100.
What are concentration warnings?
A warning appears when the displayed satellite percentage, rounded to two decimals, is greater than 5% of the whole portfolio. This is an illustrative threshold only. It does not assess suitability or risk.
How much should be core?
There is no universally suitable core percentage. This calculator reports the result of the percentages you enter and does not recommend a target allocation.
What is saved in my browser?
Core and satellite tickers and weights are saved in local browser storage on this device. The calculator does not fetch prices or fund holdings.
Related Tools
Use Portfolio Rebalancer to compare target weights with current holdings. Use ETF Overlap Detector to inspect shared positions between supported funds. Those tools provide separate calculations and are not inputs to this calculator.