Same index, in three currencies.
Convert prices and contract value between the three S&P 500 instruments. SPY-to-SPX ratio is editable to account for dividend + expense-ratio drift.
INPUTS
ENTER ONE
Cash S&P 500 index level (e.g. 5,000.00).
Defaults to 0.10. The actual ratio drifts down over the year from dividends + the ETF's expense ratio — adjust to whatever your broker is currently quoting.
How many ES contracts to size total exposure for.
TRY ONE
RESULT
SPX index5,000.00
ES future5,000.00
SPY ETF$500.00
1 ES contract value$250,000
Total exposure (1)$250,000
1 SPX pt = ES$50
1 SPX pt = SPY$0.10
1% index move50.00 pts
HOW IT WORKS
Three ways to express the same exposure. SPX is the cash index — no direct trading. ESis the e-mini future at $50 per point, the futures community's standard. SPY is the ETF — about 1/10 of SPX but drifting slightly below that ratio over the year as SPY pays dividends and bleeds 0.0945% in expense ratio. The ratio you set drives the conversion both ways; default 0.10 is close enough for ballpark, but for tight work pull the actual ratio your broker shows. ES vs. SPX usually shows a small fair-value spread (carry minus dividends to expiry) but front-month is close enough that 1:1 works for sizing. One ES contract = $50 × SPX, so at SPX 5,000 a single contract carries about $250,000 of notional.
FAQ
Why isn't SPY exactly SPX ÷ 10?
SPY is an ETF, not a derivative of the index. Its NAV is the value of its actual S&P 500 holdings divided by shares outstanding. Two things make the ratio drift below 10: dividends paid out by the ETF reduce NAV without reducing the index, and SPY's 0.0945% annual expense ratio is a slow leak. The ratio bounces around 9.95–10.05 over a year.
Why doesn't ES match SPX exactly?
ES is a futures contract priced off the index plus a fair-value spread: implied interest cost to expiry minus expected dividends. Front-month ES usually trades within a fraction of a percent of SPX, but it widens on quad-witching weeks and when rates or div expectations move.
How big is one ES contract?
ES is a $50-per-point future. At SPX 5,000 a single contract carries roughly $250,000 of notional — sized for institutional hedgers. MES (Micro E-mini) is 1/10 that size for retail.
Do you fetch live prices?
No. We compute relationships; you bring the prices. That keeps the tool free and the URL shareable. Type the current SPX (or SPY, or ES) and the other two fall out at the ratio you set.
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