diff --git a/lib/compress/zstd_compress.c b/lib/compress/zstd_compress.c
index fe59f522f..f2b9e03ed 100644
--- a/lib/compress/zstd_compress.c
+++ b/lib/compress/zstd_compress.c
@@ -1106,9 +1106,11 @@ size_t ZSTD_estimateCCtxSize(int compressionLevel)
 size_t ZSTD_estimateCStreamSize_usingCCtxParams(const ZSTD_CCtx_params* params)
 {
     RETURN_ERROR_IF(params->nbWorkers > 0, GENERIC, "Estimate CCtx size is supported for single-threaded compression only.");
-    {   size_t const CCtxSize = ZSTD_estimateCCtxSize_usingCCtxParams(params);
-        size_t const blockSize = MIN(ZSTD_BLOCKSIZE_MAX, (size_t)1 << params->cParams.windowLog);
-        size_t const inBuffSize = ((size_t)1 << params->cParams.windowLog) + blockSize;
+    {   ZSTD_compressionParameters const cParams =
+                ZSTD_getCParamsFromCCtxParams(params, 0, 0);
+        size_t const CCtxSize = ZSTD_estimateCCtxSize_usingCCtxParams(params);
+        size_t const blockSize = MIN(ZSTD_BLOCKSIZE_MAX, (size_t)1 << cParams.windowLog);
+        size_t const inBuffSize = ((size_t)1 << cParams.windowLog) + blockSize;
         size_t const outBuffSize = ZSTD_compressBound(blockSize) + 1;
         size_t const streamingSize = inBuffSize + outBuffSize;
 
diff --git a/tests/zstreamtest.c b/tests/zstreamtest.c
index e26375e07..51cb27b54 100644
--- a/tests/zstreamtest.c
+++ b/tests/zstreamtest.c
@@ -344,6 +344,20 @@ static int basicUnitTests(U32 seed, double compressibility)
         DISPLAYLEVEL(3, "OK (%u bytes) \n", (unsigned)(cstreamSize + cdictSize));
     }
 
+    /* context size functions */
+    DISPLAYLEVEL(3, "test%3i : estimate CStream size using CCtxParams : ", testNb++);
+    {   ZSTD_CCtx_params* const params = ZSTD_createCCtxParams();
+        size_t cstreamSize, cctxSize;
+        CHECK_Z( ZSTD_CCtxParams_setParameter(params, ZSTD_c_compressionLevel, 19) );
+        cstreamSize = ZSTD_estimateCStreamSize_usingCCtxParams(params);
+        CHECK_Z(cstreamSize);
+        cctxSize = ZSTD_estimateCCtxSize_usingCCtxParams(params);
+        CHECK_Z(cctxSize);
+        if (cstreamSize <= cctxSize + 2 * ZSTD_BLOCKSIZE_MAX) goto _output_error;
+        ZSTD_freeCCtxParams(params);
+        DISPLAYLEVEL(3, "OK \n");
+    }
+
     DISPLAYLEVEL(3, "test%3i : check actual CStream size : ", testNb++);
     {   size_t const s = ZSTD_sizeof_CStream(zc);
         if (ZSTD_isError(s)) goto _output_error;