diff --git a/common/util.c b/common/util.c
index 32b693a449..abaca17fe9 100644
--- a/common/util.c
+++ b/common/util.c
@@ -23,7 +23,8 @@ int numlen(int n) {
 	if (n == 0) {
 		return 1;
 	}
-	return log10(abs(n)) + 1;
+	// Account for the '-' in negative numbers.
+	return log10(abs(n)) + (n > 0 ? 1 : 2);
 }
 
 static struct modifier_key {