I'm trying to find an easy way to calculate for futures or combination of futures and other assets what the dollar equivalent move is on the price ratio line. So, for equity pairs, my understanding is that it's relatively simple. Price Ratio of [ABC Company Stock]/[DEF Company Stock] Say the current ratio is current Ratio is 0.7, and we expect a move in the ratio to 0.8. If we're long and then this is a ~14.3% move in our favour. The dollar value of such a move is 14.3% x Value of ABC Company Stock (qty x price) or Value of DEF Company Stock. (Presumably they are similar in size if you calculated your hedge ratio correctly) What would be the equivalent if you were calculating the price ratio of futures contracts? [Future A] / [Future B] For a move on the price ratio from .7 to .8 ... the same 14.3% move, what would you multiply that by? The notional value? That doesn't make sense because the notional sizes could be very different, and you care about size of tick movement. You could abandon the price ratio and fix the hedge ratio and convert to dollars. (e.g., Future A x Val 1 Pt x Hedge Qty - Future B x Val 1 Pt x Hedge Qty). But this representation is only valid for small movements in the price ratio as larger movements will require a different hedge ratio. So for large moves in price ratio, is there an easy way to calculate what the dollar value of such a move is, assuming dynamic adjustment of hedge ratios? I'm trying to understand prior to getting into a trade, what the risk is, and how much I expect to make from it. But it's difficult without a way to convert a move in price ratio to dollars?