diff --git a/code/modules/admin/topic.dm b/code/modules/admin/topic.dm
index aba21d69f8..2f089e793b 100644
--- a/code/modules/admin/topic.dm
+++ b/code/modules/admin/topic.dm
@@ -480,7 +480,8 @@
 				if(minutes > GLOB.CMinutes)
 					mins = minutes - GLOB.CMinutes
 				mins = input(usr,"How long (in minutes)? (Default: 1440)","Ban time",mins ? mins : 1440) as num|null
-				if(!mins)
+				if(mins <= 0)
+					to_chat(usr, "<span class='danger'>[mins] is not a valid duration.</span>")
 					return
 				minutes = GLOB.CMinutes + mins
 				duration = GetExp(minutes)
@@ -914,7 +915,8 @@
 			switch(alert("Temporary Ban?",,"Yes","No", "Cancel"))
 				if("Yes")
 					var/mins = input(usr,"How long (in minutes)?","Ban time",1440) as num|null
-					if(!mins)
+					if(mins <= 0)
+						to_chat(usr, "<span class='danger'>[mins] is not a valid duration.</span>")
 						return
 					var/reason = input(usr,"Please State Reason.","Reason") as message|null
 					if(!reason)
@@ -1109,7 +1111,8 @@
 		switch(alert("Temporary Ban?",,"Yes","No", "Cancel"))
 			if("Yes")
 				var/mins = input(usr,"How long (in minutes)?","Ban time",1440) as num|null
-				if(!mins)
+				if(mins <= 0)
+					to_chat(usr, "<span class='danger'>[mins] is not a valid duration.</span>")
 					return
 				var/reason = input(usr,"Please State Reason.","Reason") as message|null
 				if(!reason)