diff --git a/apps/openmw/mwmechanics/creaturestats.cpp b/apps/openmw/mwmechanics/creaturestats.cpp
index c99f87e833..570547e0d9 100644
--- a/apps/openmw/mwmechanics/creaturestats.cpp
+++ b/apps/openmw/mwmechanics/creaturestats.cpp
@@ -44,7 +44,7 @@ namespace MWMechanics
         float max = getFatigue().getModified();
         float current = getFatigue().getCurrent();
 
-        float normalised = floor(max) == 0 ? 1 : std::max (0.0f, current / max);
+        float normalised = std::floor(max) == 0 ? 1 : std::max (0.0f, current / max);
 
         const MWWorld::Store<ESM::GameSetting> &gmst =
             MWBase::Environment::get().getWorld()->getStore().get<ESM::GameSetting>();
diff --git a/apps/openmw/mwmechanics/trading.cpp b/apps/openmw/mwmechanics/trading.cpp
index 750fd803d4..d9ec66bab2 100644
--- a/apps/openmw/mwmechanics/trading.cpp
+++ b/apps/openmw/mwmechanics/trading.cpp
@@ -71,10 +71,10 @@ namespace MWMechanics
         int initialMerchantOffer = std::abs(merchantOffer);
 
         if ( !buying && (finalPrice > initialMerchantOffer) ) {
-            skillGain = floor(100.f * (finalPrice - initialMerchantOffer) / finalPrice);
+            skillGain = std::floor(100.f * (finalPrice - initialMerchantOffer) / finalPrice);
         }
         else if ( buying && (finalPrice < initialMerchantOffer) ) {
-            skillGain = floor(100.f * (initialMerchantOffer - finalPrice) / initialMerchantOffer);
+            skillGain = std::floor(100.f * (initialMerchantOffer - finalPrice) / initialMerchantOffer);
         }
         player.getClass().skillUsageSucceeded(player, ESM::Skill::Mercantile, 0, skillGain);