diff --git a/helper/resource/id.go b/helper/resource/id.go
index 1cde67c1a..44949550e 100644
--- a/helper/resource/id.go
+++ b/helper/resource/id.go
@@ -18,6 +18,11 @@ func UniqueId() string {
 	return PrefixedUniqueId(UniqueIdPrefix)
 }
 
+// UniqueIDSuffixLength is the string length of the suffix generated by
+// PrefixedUniqueId. This can be used by length validation functions to
+// ensure prefixes are the correct length for the target field.
+const UniqueIDSuffixLength = 26
+
 // Helper for a resource to generate a unique identifier w/ given prefix
 //
 // After the prefix, the ID consists of an incrementing 26 digit value (to match