diff --git a/README.md b/README.md
index ba6f89ae22..8e8d42b05d 100644
--- a/README.md
+++ b/README.md
@@ -2,6 +2,7 @@
 
 [![GitHub Action](https://img.shields.io/github/actions/workflow/status/raviqqe/melior/test.yaml?branch=main&style=flat-square)](https://github.com/raviqqe/melior/actions?query=workflow%3Atest)
 [![Crate](https://img.shields.io/crates/v/melior.svg?style=flat-square)](https://crates.io/crates/melior)
+![API coverage](https://img.shields.io/badge/api%20coverage-36%25-blue.svg?style=flat-square)
 [![License](https://img.shields.io/github/license/raviqqe/melior.svg?style=flat-square)](LICENSE)
 
 The rustic MLIR bindings for Rust
diff --git a/tools/api_completeness.sh b/tools/api_completeness.sh
new file mode 100755
index 0000000000..0117d5e606
--- /dev/null
+++ b/tools/api_completeness.sh
@@ -0,0 +1,21 @@
+#!/bin/sh
+
+set -e
+
+cd $(dirname $0)/..
+cd melior
+
+count() {
+  grep -o '\(m\|M\)lir[A-Z][a-zA-Z0-9]*' | sort -u | wc -l
+}
+
+implemented_count() {
+  cargo install cargo-expand
+  cargo expand | count
+}
+
+upstream_count() {
+  cat $(find $(brew --prefix llvm)/include/mlir-c -type f) | count
+}
+
+echo $(implemented_count) / $(upstream_count) | bc -l