i What this calculator does
A correlation calculator measures how closely two instruments move together - from +1 (perfectly aligned) to -1 (perfectly opposite). For traders holding multiple open positions, knowing the correlation between instruments is essential to avoid accidentally doubling exposure in the same direction, which multiplies risk beyond what individual position sizing suggests.
This calculator is for educational purposes only. Results are estimates. Not financial advice.
How to Use This Calculator
Key Takeaways
- It means 80% of the price movements in one pair are explained by movements in the other.
- Use this calculator consistently - not occasionally - to build disciplined trading habits.
- Calculator results are starting points. Verify critical values with your broker.
Frequently Asked Questions
What does a correlation of 0.8 between two pairs mean?
It means 80% of the price movements in one pair are explained by movements in the other. Trading both long is similar to doubling your position size on a single instrument.
Is USD/ZAR correlated with EUR/USD?
USD/ZAR and EUR/USD have a moderate negative correlation - when the USD strengthens (EUR/USD falls), USD/ZAR typically rises. The correlation varies with SA-specific risk events.
What correlation level should make me avoid holding both positions?
Above 0.7 positive correlation, holding both long positions effectively doubles your directional exposure. Most professional traders avoid adding correlated positions beyond a 0.5 threshold.
How do I get historical returns data for currency pairs?
Export daily closing prices from TradingView or MetaTrader, then calculate the daily percentage changes. Enter these as your return series.
Can correlation change over time?
Yes. Correlations are not fixed. They tend to increase during risk-off events (global crises) when all risk assets move together. Calculate rolling correlations rather than assuming static relationships.
What is a negative correlation useful for?
A strong negative correlation (-0.7 or below) means one position partially hedges the other. This can reduce overall portfolio volatility but also limits upside.
Does this work for JSE shares?
Yes. Enter daily percentage returns for any two instruments - the calculation method is identical regardless of instrument type.
What counts as a strong correlation between two pairs?
Correlation values closer to +1 or -1 indicate a strong relationship, generally above 0.7 or below -0.7 is considered meaningfully strong, while values near zero suggest little to no consistent relationship between the two instruments.
Does correlation stay constant over time?
No, correlation between any two instruments can shift meaningfully depending on market conditions and time period, a pair that's strongly correlated over one stretch can decouple significantly during another, worth checking correlation periodically rather than assuming it's fixed.
Why does a negative correlation matter for my portfolio?
Negatively correlated instruments tend to move in opposite directions, holding some can genuinely help offset risk in your overall portfolio, unlike positively correlated positions which tend to amplify your combined exposure in the same direction.
Can two currency pairs be highly correlated without sharing a currency?
Yes, correlation reflects how prices actually move together historically, not simply whether pairs share a currency, some pairs without any common currency can still show meaningful correlation due to broader market or economic linkages.
How many data points should I use for a meaningful correlation reading?
More data generally produces a more statistically reliable correlation figure, very short lookback periods can produce misleadingly high or low readings driven by a handful of unusual price moves rather than a genuine underlying relationship.
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