diff --git a/components/trade/TradeSummary.tsx b/components/trade/TradeSummary.tsx
index 8151281c..c0926cee 100644
--- a/components/trade/TradeSummary.tsx
+++ b/components/trade/TradeSummary.tsx
@@ -53,12 +53,12 @@ const TradeSummary = ({
             ? mangoAccount.simHealthRatioWithPerpAskUiChanges(
                 group,
                 selectedMarket.perpMarketIndex,
-                parseFloat(tradeForm.baseSize)
+                parseFloat(tradeForm.baseSize) || 0
               )
             : mangoAccount.simHealthRatioWithPerpBidUiChanges(
                 group,
                 selectedMarket.perpMarketIndex,
-                parseFloat(tradeForm.baseSize)
+                parseFloat(tradeForm.baseSize) || 0
               )
       }
     } catch (e) {