diff --git a/src/arena_allocator.c b/src/arena_allocator.c
new file mode 100644
index 0000000..01374b0
--- /dev/null
+++ b/src/arena_allocator.c
@@ -0,0 +1,28 @@
+#include "arena_allocator.h"
+#include <assert.h>
+#include <math.h>
+#include <stddef.h>
+#include <stdlib.h>
+
+Arena arena_init(size_t capacity) {
+  Arena result = {.capacity = capacity, .size = 0, .data = malloc(capacity)};
+  assert(result.data != NULL);
+  return result;
+}
+
+void arena_deinit(Arena *arena) {
+  free(arena->data);
+  *arena = (Arena){.capacity = NAN, .size = 0, .data = NULL};
+}
+
+void *arena_alloc(Arena *arena, size_t size) {
+  assert(arena->size + size <= arena->capacity);
+  void *result = &arena->data[arena->size];
+  arena->size += size;
+  return result;
+}
+
+void *arena_clear(Arena *arena) {
+  arena->size = 0;
+  return arena->data;
+}
diff --git a/src/arena_allocator.h b/src/arena_allocator.h
new file mode 100644
index 0000000..c883209
--- /dev/null
+++ b/src/arena_allocator.h
@@ -0,0 +1,15 @@
+#pragma once
+
+#include <stddef.h>
+
+typedef struct {
+  size_t capacity;
+  size_t size;
+  void *data;
+} Arena;
+
+Arena arena_init(size_t capacity);
+void arena_deinit(Arena *arena);
+
+void *arena_alloc(Arena *arena, size_t size);
+void *arena_clear(Arena *arena);