Comprehensive Guide
Learn more in our Investing Guide.
How it works
Gold's portfolio case rests on one statistical property: its long-run correlation with stocks hovers near zero, and combining imperfectly correlated assets lowers total volatility below any simple average — sometimes below either component alone. This calculator applies the two-asset variance formula directly: portfolio volatility equals the square root of w²σg² + (1−w)²σs² + 2w(1−w)ρσsσg, where ρ is the correlation you supply. Moving 10% of a 16%-volatility stock portfolio into 15%-volatility gold at 0.10 correlation drops blended volatility to roughly 14.6% — a 1.4-point reduction bought with about 0.2 points of expected return, assuming 7% stocks against 5% gold. The weight sweep exposes the shape of the trade-off: benefits strengthen as correlation falls toward zero or negative, and there is a mathematically optimal minimum-variance weight the schedule locates for your inputs. Three honesty notes temper everything: correlation is regime-dependent and can spike upward in panics exactly when diversification is needed most; gold produces no cash flow, so its expected return is assumption rather than yield; and lower volatility is a comfort feature, not a return feature — the calm costs basis points of growth by construction.Formula
σp = √(w²σg² + (1−w)²σs² + 2w(1−w)·ρ·σs·σg)
Tips
- Correlation is the active ingredient — test 0.3 panic-case alongside the 0.1 average.
- Most studies put useful gold sleeves at 5–15%, past which drag outweighs calm.
- Gold's zero yield means its expected return is faith plus scarcity, not cash flow.
- Rebalance annually or the sleeve drifts away from the weight you chose here.
- Compare against low-correlation alternatives (TIPS, short bonds) doing the same job.
Frequently asked questions
How much gold should a portfolio hold?
Most institutional and academic analyses land at 5–15% for volatility reduction, with diminishing and eventually negative effects beyond. At 10% with realistic correlations the calculator shows roughly a point or more of volatility trimmed for modest return sacrifice. Beyond 25–30%, gold's own price swings increasingly dominate and expected return erodes without offsetting benefit.
Does gold actually reduce portfolio volatility?
Historically yes on average, because gold's correlation with equities has run near zero over long samples. The two-asset formula shows even modestly positive correlation produces diversification when vols differ. The caveat: in acute crises correlations sometimes rise toward positive territory, shrinking the benefit precisely when portfolios need it — hence testing panic-case assumptions here matters.
What correlation does gold have with stocks?
Long-run estimates cluster near zero, oscillating between mildly negative and moderately positive across regimes — roughly −0.2 to +0.4 depending on the decade and crisis. Gold's strongest diversification stretches coincide with monetary stress and inflation scares. Treat any single correlation estimate as a central scenario, and stress-test the edges with the slider.
Is gold a good inflation hedge?
Over very long horizons and specific inflationary regimes (the 1970s, post-2021 surge), yes meaningfully; across all decades, inconsistently. Gold's real price spent long stretches going nowhere between spikes. It functions better as a crisis-and-currency hedge than a reliable CPI tracker, and the volatility math here captures its risk side that hedging narratives omit.
Why does adding gold lower expected return?
Because gold generates no earnings, rent or interest — its long-run return comes from price change alone, historically trailing productive assets. Blending 10% of a 7% expected-return portfolio into 5% gold mechanically subtracts 0.2 points. Whether that insurance premium is worthwhile depends on how much you value the smoother ride the correlation provides.