diff --git a/icu4c/source/common/ucnv.c b/icu4c/source/common/ucnv.c
index b652f6c16c0..a9a043ed648 100644
--- a/icu4c/source/common/ucnv.c
+++ b/icu4c/source/common/ucnv.c
@@ -751,7 +751,7 @@ int32_t   ucnv_fromUChars (const UConverter * converter,
     {
       ucnv_fromUnicode (&myConverter,
 			&myTarget,
-			target + targetSize,
+			myTarget_limit,
 			&mySource,
 			mySource_limit,
 			NULL,
diff --git a/icu4c/source/common/unistr.cpp b/icu4c/source/common/unistr.cpp
index 8a4925d9a42..4c6855a7263 100644
--- a/icu4c/source/common/unistr.cpp
+++ b/icu4c/source/common/unistr.cpp
@@ -790,7 +790,7 @@ UnicodeString::extract(UTextOffset start,
   // perform the conversion
   // there is no loop here since we assume the buffer is large enough
 
-  ucnv_fromUnicode(converter, &myTarget,  myTarget + arraySize,
+  ucnv_fromUnicode(converter, &myTarget,  myTargetLimit,
            &mySource, mySourceEnd, NULL, TRUE, &status);
 
   // close the converter