diff --git a/m-array.h b/m-array.h
index 1c57560d..603937bb 100644
--- a/m-array.h
+++ b/m-array.h
@@ -84,8 +84,9 @@
    )
 
 // Compute alloc from the requested size.
-#define ARRAYI_EXPECTED_SIZE     8
-#define ARRAYI_INC_ALLOC_SIZE(n) (M_MAX(ARRAYI_EXPECTED_SIZE, (n))*2)
+// NOTE: EXPECTED_SIZE can be overloaded by the given oplist.
+#define ARRAYI_INC_ALLOC_SIZE(oplist, n)        \
+  (M_MAX(M_GET_EXPECTED_SIZE oplist, (n))*2)
 
 // Internal definition.
 #define ARRAYI_DEF2(name, type, oplist)                                 \
@@ -149,7 +150,7 @@
             && d->size <= d->alloc &&  s->size <= s->alloc);            \
     if (d == s) return;                                                 \
     if (s->size > d->alloc) {                                           \
-      size_t alloc = ARRAYI_INC_ALLOC_SIZE(s->size);                    \
+      size_t alloc = ARRAYI_INC_ALLOC_SIZE(oplist, s->size);            \
       type *ptr = M_GET_REALLOC oplist (type, d->ptr, alloc);           \
       if (ptr == NULL) {                                                \
         M_MEMORY_FULL(sizeof (type) * alloc);                           \
@@ -219,7 +220,7 @@
     assert (v != NULL && v->size <= v->alloc);                          \
     if (v->size >= v->alloc) {                                          \
       assert(v->size == v->alloc);                                      \
-      size_t alloc = ARRAYI_INC_ALLOC_SIZE(v->alloc);                   \
+      size_t alloc = ARRAYI_INC_ALLOC_SIZE(oplist, v->alloc);           \
       assert (alloc > v->size);                                         \
       type *ptr = M_GET_REALLOC oplist (type, v->ptr, alloc);           \
       if (ptr == NULL) {                                                \
@@ -262,7 +263,7 @@
     assert (v != NULL && key <= v->size && v->size <= v->alloc);        \
     if (v->size >= v->alloc) {                                          \
       assert(v->size == v->alloc);                                      \
-      size_t alloc = ARRAYI_INC_ALLOC_SIZE(v->alloc);                   \
+      size_t alloc = ARRAYI_INC_ALLOC_SIZE(oplist, v->alloc);           \
       assert (alloc > v->size);                                         \
       type *ptr = M_GET_REALLOC oplist (type, v->ptr, alloc);           \
       if (ptr == NULL) {                                                \
@@ -314,7 +315,7 @@
     if (v->size <= size) {                                              \
       /* Increase size of array */                                      \
       if (size > v->alloc) {                                            \
-        size_t alloc = ARRAYI_INC_ALLOC_SIZE (size) ;                   \
+        size_t alloc = ARRAYI_INC_ALLOC_SIZE(oplist, size) ;            \
         type *ptr = M_GET_REALLOC oplist (type, v->ptr, alloc);         \
         if (ptr == NULL) {                                              \
           M_MEMORY_FULL(sizeof (type) * alloc);                         \
@@ -388,7 +389,7 @@
     assert(i < v->size && j <= v->size && i < j);                       \
     size_t size = v->size + (j-i);                                      \
     if (size > v->alloc) {                                              \
-      size_t alloc = ARRAYI_INC_ALLOC_SIZE (size) ;                     \
+      size_t alloc = ARRAYI_INC_ALLOC_SIZE(oplist, size) ;              \
       type *ptr = M_GET_REALLOC oplist (type, v->ptr, alloc);           \
       if (ptr == NULL) {                                                \
         M_MEMORY_FULL(sizeof (type) * alloc);                           \
diff --git a/m-core.h b/m-core.h
index ed9d2d73..c0ca267d 100644
--- a/m-core.h
+++ b/m-core.h
@@ -664,6 +664,7 @@
 #define M_IN_STR_IN_STR(a)       ,a,
 #define M_SEPARATOR_SEPARATOR(a) ,a,
 #define M_EXT_ALGO_EXT_ALGO(a)   ,a,
+#define M_EXPECTED_SIZE_EXPECTED_SIZE(a) ,a,
 
 /* From an oplist - an unorded list of methods : like "INIT(mpz_init),CLEAR(mpz_clear),SET(mpz_set)" -
    Return the given method in the oplist or the default method.
@@ -717,6 +718,7 @@
 #define M_GET_IN_STR(...)    M_GET_METHOD(IN_STR,      M_NO_DEFAULT,       __VA_ARGS__)
 #define M_GET_SEPARATOR(...) M_GET_METHOD(SEPARATOR,   ',',                __VA_ARGS__)
 #define M_GET_EXT_ALGO(...)  M_GET_METHOD(EXT_ALGO,    M_NO_EXT_ALGO,      __VA_ARGS__)
+#define M_GET_EXPECTED_SIZE(...) M_GET_METHOD(EXPECTED_SIZE, 8,            __VA_ARGS__)
 
 /* Define the default method.
    NOTE: MEMSET_DEFAULT & MEMCPY_DEFAULT are NOT compatible with the '[1]' tricks