diff --git a/src/dec/idec.c b/src/dec/idec.c
index a22232bf..5e127be9 100644
--- a/src/dec/idec.c
+++ b/src/dec/idec.c
@@ -98,8 +98,8 @@ static int AppendToMemBuffer(WebPIDecoder* const idec,
   if (mem->end_ + data_size > mem->buf_size_) {  // Need some free memory
     int p;
     uint8_t* new_buf = NULL;
-    const int num_chunks = (MemDataSize(mem) + data_size + CHUNK_SIZE - 1)
-        / CHUNK_SIZE;
+    const size_t num_chunks =
+        (MemDataSize(mem) + data_size + CHUNK_SIZE - 1) / CHUNK_SIZE;
     const size_t new_size = num_chunks * CHUNK_SIZE;
     const uint8_t* const base = mem->buf_ + mem->start_;
 
diff --git a/src/utils/alpha.c b/src/utils/alpha.c
index 9d9e31fb..831d95f6 100644
--- a/src/utils/alpha.c
+++ b/src/utils/alpha.c
@@ -116,7 +116,7 @@ static int EncodeZlibTCoder(const uint8_t* data, int width, int height,
       best.literal = data[n];
       best.len = 1;
       for (dist = 1; dist <= MAX_DIST && dist <= n; ++dist) {
-        const int pos = n - dist;
+        const size_t pos = n - dist;
         const size_t min_len = best.len - 1;
         size_t len;