diff --git a/src/dat/nbt.c b/src/dat/nbt.c
index 668de65..2ca6d5f 100644
--- a/src/dat/nbt.c
+++ b/src/dat/nbt.c
@@ -98,3 +98,17 @@ int nbt_prim_tagsize(u8 tag) {
 	default:      return -1;
 	}
 }
+
+int nbt_isprim(u8 tag) {
+	switch (tag) {
+	case NBT_I8:
+	case NBT_I16:
+	case NBT_I32:
+	case NBT_F32:
+	case NBT_I64:
+	case NBT_F64:
+		return 1;
+	default:
+		return 0;
+	}
+}
diff --git a/src/dat/nbt.h b/src/dat/nbt.h
index 0295f40..be32a77 100644
--- a/src/dat/nbt.h
+++ b/src/dat/nbt.h
@@ -36,5 +36,10 @@ enum nbt_tagid {
 
 int nbt_proc(void **restrict datout, u8 const *restrict buf, size_t len);
 
+/* checks whether the tag is a primitive data tag. (not recommended for filtering tags, use a `switch`)
+ * returns a boolean value. */
+atrb_const int nbt_isprim(u8 tag);
+
+
 /* gets the tag size of primitive types, returns `>0` on success, `<0` on failure */
 atrb_const int nbt_prim_tagsize(u8 tag);