diff --git a/public/js/tabulator/filters/extendedHeaderFilter.js b/public/js/tabulator/filters/extendedHeaderFilter.js
index 6a995343f..7bf86c119 100644
--- a/public/js/tabulator/filters/extendedHeaderFilter.js
+++ b/public/js/tabulator/filters/extendedHeaderFilter.js
@@ -13,7 +13,7 @@ function parseFilterExpression(expression)
 
 			andParts.forEach(term => {
 
-				const comparisonMatch = term.match(/^(<=|>=|<|>|=|!=)\s*(\d+(?:[.,]\d+)?)$/);
+				const comparisonMatch = term.match(/^(<=|>=|<|>|=|!=)\s*(-?\d+(?:[.,]\d+)?)$/);
 
 				if (comparisonMatch)
 				{