diff --git a/reftable/basics.h b/reftable/basics.h
index 2f855cd724..4c3ac963a3 100644
--- a/reftable/basics.h
+++ b/reftable/basics.h
@@ -51,8 +51,10 @@ int names_length(char **names);
 void *reftable_malloc(size_t sz);
 void *reftable_realloc(void *p, size_t sz);
 void reftable_free(void *p);
-void *reftable_calloc(size_t sz);
+void *reftable_calloc(size_t nelem, size_t elsize);
 
+#define REFTABLE_ALLOC_ARRAY(x, alloc) (x) = reftable_malloc(st_mult(sizeof(*(x)), (alloc)))
+#define REFTABLE_CALLOC_ARRAY(x, alloc) (x) = reftable_calloc((alloc), sizeof(*(x)))
 #define REFTABLE_REALLOC_ARRAY(x, alloc) (x) = reftable_realloc((x), st_mult(sizeof(*(x)), (alloc)))
 #define REFTABLE_ALLOC_GROW(x, nr, alloc) \
 	do { \
diff --git a/reftable/block_test.c b/reftable/block_test.c
index dedb05c7d8..e162c6e33f 100644
--- a/reftable/block_test.c
+++ b/reftable/block_test.c
@@ -36,7 +36,7 @@ static void test_block_read_write(void)
 	int j = 0;
 	struct strbuf want = STRBUF_INIT;
 
-	block.data = reftable_calloc(block_size);
+	REFTABLE_CALLOC_ARRAY(block.data, block_size);
 	block.len = block_size;
 	block.source = malloc_block_source();
 	block_writer_init(&bw, BLOCK_TYPE_REF, block.data, block_size,
diff --git a/reftable/blocksource.c b/reftable/blocksource.c
index 8c41e3c70f..eeed254ba9 100644
--- a/reftable/blocksource.c
+++ b/reftable/blocksource.c
@@ -29,7 +29,7 @@ static int strbuf_read_block(void *v, struct reftable_block *dest, uint64_t off,
 {
 	struct strbuf *b = v;
 	assert(off + size <= b->len);
-	dest->data = reftable_calloc(size);
+	REFTABLE_CALLOC_ARRAY(dest->data, size);
 	memcpy(dest->data, b->buf + off, size);
 	dest->len = size;
 	return size;
@@ -132,7 +132,7 @@ int reftable_block_source_from_file(struct reftable_block_source *bs,
 		return REFTABLE_IO_ERROR;
 	}
 
-	p = reftable_calloc(sizeof(*p));
+	REFTABLE_CALLOC_ARRAY(p, 1);
 	p->size = st.st_size;
 	p->data = xmmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 	close(fd);
diff --git a/reftable/iter.c b/reftable/iter.c
index a8d174c040..8b5ebf6183 100644
--- a/reftable/iter.c
+++ b/reftable/iter.c
@@ -160,8 +160,7 @@ int new_indexed_table_ref_iter(struct indexed_table_ref_iter **dest,
 			       int oid_len, uint64_t *offsets, int offset_len)
 {
 	struct indexed_table_ref_iter empty = INDEXED_TABLE_REF_ITER_INIT;
-	struct indexed_table_ref_iter *itr =
-		reftable_calloc(sizeof(struct indexed_table_ref_iter));
+	struct indexed_table_ref_iter *itr = reftable_calloc(1, sizeof(*itr));
 	int err = 0;
 
 	*itr = empty;
diff --git a/reftable/merged.c b/reftable/merged.c
index c258ce953e..2031fd51b4 100644
--- a/reftable/merged.c
+++ b/reftable/merged.c
@@ -190,7 +190,7 @@ int reftable_new_merged_table(struct reftable_merged_table **dest,
 		}
 	}
 
-	m = reftable_calloc(sizeof(struct reftable_merged_table));
+	REFTABLE_CALLOC_ARRAY(m, 1);
 	m->stack = stack;
 	m->stack_len = n;
 	m->min = first_min;
@@ -240,7 +240,7 @@ static int merged_table_seek_record(struct reftable_merged_table *mt,
 				    struct reftable_record *rec)
 {
 	struct reftable_iterator *iters = reftable_calloc(
-		sizeof(struct reftable_iterator) * mt->stack_len);
+		mt->stack_len, sizeof(*iters));
 	struct merged_iter merged = {
 		.stack = iters,
 		.typ = reftable_record_type(rec),
diff --git a/reftable/merged_test.c b/reftable/merged_test.c
index e05351e035..e233a9d581 100644
--- a/reftable/merged_test.c
+++ b/reftable/merged_test.c
@@ -93,10 +93,12 @@ merged_table_from_records(struct reftable_ref_record **refs,
 	int i = 0;
 	struct reftable_merged_table *mt = NULL;
 	int err;
-	struct reftable_table *tabs =
-		reftable_calloc(n * sizeof(struct reftable_table));
-	*readers = reftable_calloc(n * sizeof(struct reftable_reader *));
-	*source = reftable_calloc(n * sizeof(**source));
+	struct reftable_table *tabs;
+
+	REFTABLE_CALLOC_ARRAY(tabs, n);
+	REFTABLE_CALLOC_ARRAY(*readers, n);
+	REFTABLE_CALLOC_ARRAY(*source, n);
+
 	for (i = 0; i < n; i++) {
 		write_test_table(&buf[i], refs[i], sizes[i]);
 		block_source_from_strbuf(&(*source)[i], &buf[i]);
@@ -266,10 +268,12 @@ merged_table_from_log_records(struct reftable_log_record **logs,
 	int i = 0;
 	struct reftable_merged_table *mt = NULL;
 	int err;
-	struct reftable_table *tabs =
-		reftable_calloc(n * sizeof(struct reftable_table));
-	*readers = reftable_calloc(n * sizeof(struct reftable_reader *));
-	*source = reftable_calloc(n * sizeof(**source));
+	struct reftable_table *tabs;
+
+	REFTABLE_CALLOC_ARRAY(tabs, n);
+	REFTABLE_CALLOC_ARRAY(*readers, n);
+	REFTABLE_CALLOC_ARRAY(*source, n);
+
 	for (i = 0; i < n; i++) {
 		write_test_log_table(&buf[i], logs[i], sizes[i], i + 1);
 		block_source_from_strbuf(&(*source)[i], &buf[i]);
@@ -412,7 +416,7 @@ static void test_default_write_opts(void)
 	};
 	int err;
 	struct reftable_block_source source = { NULL };
-	struct reftable_table *tab = reftable_calloc(sizeof(*tab) * 1);
+	struct reftable_table *tab = reftable_calloc(1, sizeof(*tab));
 	uint32_t hash_id;
 	struct reftable_reader *rd = NULL;
 	struct reftable_merged_table *merged = NULL;
diff --git a/reftable/publicbasics.c b/reftable/publicbasics.c
index bcb82530d6..44b84a125e 100644
--- a/reftable/publicbasics.c
+++ b/reftable/publicbasics.c
@@ -37,8 +37,9 @@ void reftable_free(void *p)
 		free(p);
 }
 
-void *reftable_calloc(size_t sz)
+void *reftable_calloc(size_t nelem, size_t elsize)
 {
+	size_t sz = st_mult(nelem, elsize);
 	void *p = reftable_malloc(sz);
 	memset(p, 0, sz);
 	return p;
diff --git a/reftable/reader.c b/reftable/reader.c
index 64dc366fb1..3e0de5e8ad 100644
--- a/reftable/reader.c
+++ b/reftable/reader.c
@@ -539,8 +539,7 @@ static int reader_seek_indexed(struct reftable_reader *r,
 
 	if (err == 0) {
 		struct table_iter empty = TABLE_ITER_INIT;
-		struct table_iter *malloced =
-			reftable_calloc(sizeof(struct table_iter));
+		struct table_iter *malloced = reftable_calloc(1, sizeof(*malloced));
 		*malloced = empty;
 		table_iter_copy_from(malloced, &next);
 		iterator_from_table_iter(it, malloced);
@@ -635,8 +634,7 @@ void reader_close(struct reftable_reader *r)
 int reftable_new_reader(struct reftable_reader **p,
 			struct reftable_block_source *src, char const *name)
 {
-	struct reftable_reader *rd =
-		reftable_calloc(sizeof(struct reftable_reader));
+	struct reftable_reader *rd = reftable_calloc(1, sizeof(*rd));
 	int err = init_reader(rd, src, name);
 	if (err == 0) {
 		*p = rd;
@@ -711,7 +709,7 @@ static int reftable_reader_refs_for_unindexed(struct reftable_reader *r,
 					      uint8_t *oid)
 {
 	struct table_iter ti_empty = TABLE_ITER_INIT;
-	struct table_iter *ti = reftable_calloc(sizeof(struct table_iter));
+	struct table_iter *ti = reftable_calloc(1, sizeof(*ti));
 	struct filtering_ref_iterator *filter = NULL;
 	struct filtering_ref_iterator empty = FILTERING_REF_ITERATOR_INIT;
 	int oid_len = hash_size(r->hash_id);
diff --git a/reftable/readwrite_test.c b/reftable/readwrite_test.c
index b8a3224016..91ea7a10ef 100644
--- a/reftable/readwrite_test.c
+++ b/reftable/readwrite_test.c
@@ -56,7 +56,9 @@ static void write_table(char ***names, struct strbuf *buf, int N,
 	int i = 0, n;
 	struct reftable_log_record log = { NULL };
 	const struct reftable_stats *stats = NULL;
-	*names = reftable_calloc(sizeof(char *) * (N + 1));
+
+	REFTABLE_CALLOC_ARRAY(*names, N + 1);
+
 	reftable_writer_set_limits(w, update_index, update_index);
 	for (i = 0; i < N; i++) {
 		char name[100];
@@ -188,7 +190,7 @@ static void test_log_overflow(void)
 static void test_log_write_read(void)
 {
 	int N = 2;
-	char **names = reftable_calloc(sizeof(char *) * (N + 1));
+	char **names = reftable_calloc(N + 1, sizeof(*names));
 	int err;
 	struct reftable_write_options opts = {
 		.block_size = 256,
@@ -519,7 +521,7 @@ static void test_table_read_write_seek_index(void)
 static void test_table_refs_for(int indexed)
 {
 	int N = 50;
-	char **want_names = reftable_calloc(sizeof(char *) * (N + 1));
+	char **want_names = reftable_calloc(N + 1, sizeof(*want_names));
 	int want_names_len = 0;
 	uint8_t want_hash[GIT_SHA1_RAWSZ];
 
diff --git a/reftable/record_test.c b/reftable/record_test.c
index 2876db7d27..999366ad46 100644
--- a/reftable/record_test.c
+++ b/reftable/record_test.c
@@ -231,8 +231,8 @@ static void test_reftable_log_record_roundtrip(void)
 				.value_type = REFTABLE_LOG_UPDATE,
 				.value = {
 					.update = {
-						.new_hash = reftable_calloc(GIT_SHA1_RAWSZ),
-						.old_hash = reftable_calloc(GIT_SHA1_RAWSZ),
+						.new_hash = reftable_calloc(GIT_SHA1_RAWSZ, 1),
+						.old_hash = reftable_calloc(GIT_SHA1_RAWSZ, 1),
 						.name = xstrdup("old name"),
 						.email = xstrdup("old@email"),
 						.message = xstrdup("old message"),
diff --git a/reftable/refname.c b/reftable/refname.c
index 9573496932..7570e4acf9 100644
--- a/reftable/refname.c
+++ b/reftable/refname.c
@@ -140,8 +140,8 @@ int validate_ref_record_addition(struct reftable_table tab,
 {
 	struct modification mod = {
 		.tab = tab,
-		.add = reftable_calloc(sizeof(char *) * sz),
-		.del = reftable_calloc(sizeof(char *) * sz),
+		.add = reftable_calloc(sz, sizeof(*mod.add)),
+		.del = reftable_calloc(sz, sizeof(*mod.del)),
 	};
 	int i = 0;
 	int err = 0;
diff --git a/reftable/stack.c b/reftable/stack.c
index 1dfab99e96..d084823a92 100644
--- a/reftable/stack.c
+++ b/reftable/stack.c
@@ -50,8 +50,7 @@ static ssize_t reftable_fd_write(void *arg, const void *data, size_t sz)
 int reftable_new_stack(struct reftable_stack **dest, const char *dir,
 		       struct reftable_write_options config)
 {
-	struct reftable_stack *p =
-		reftable_calloc(sizeof(struct reftable_stack));
+	struct reftable_stack *p = reftable_calloc(1, sizeof(*p));
 	struct strbuf list_file_name = STRBUF_INIT;
 	int err = 0;
 
@@ -114,7 +113,7 @@ int read_lines(const char *filename, char ***namesp)
 	int err = 0;
 	if (fd < 0) {
 		if (errno == ENOENT) {
-			*namesp = reftable_calloc(sizeof(char *));
+			REFTABLE_CALLOC_ARRAY(*namesp, 1);
 			return 0;
 		}
 
@@ -191,8 +190,7 @@ void reftable_stack_destroy(struct reftable_stack *st)
 static struct reftable_reader **stack_copy_readers(struct reftable_stack *st,
 						   int cur_len)
 {
-	struct reftable_reader **cur =
-		reftable_calloc(sizeof(struct reftable_reader *) * cur_len);
+	struct reftable_reader **cur = reftable_calloc(cur_len, sizeof(*cur));
 	int i = 0;
 	for (i = 0; i < cur_len; i++) {
 		cur[i] = st->readers[i];
@@ -208,9 +206,9 @@ static int reftable_stack_reload_once(struct reftable_stack *st, char **names,
 	int err = 0;
 	int names_len = names_length(names);
 	struct reftable_reader **new_readers =
-		reftable_calloc(sizeof(struct reftable_reader *) * names_len);
+		reftable_calloc(names_len, sizeof(*new_readers));
 	struct reftable_table *new_tables =
-		reftable_calloc(sizeof(struct reftable_table) * names_len);
+		reftable_calloc(names_len, sizeof(*new_tables));
 	int new_readers_len = 0;
 	struct reftable_merged_table *new_merged = NULL;
 	struct strbuf table_path = STRBUF_INIT;
@@ -344,7 +342,7 @@ static int reftable_stack_reload_maybe_reuse(struct reftable_stack *st,
 				goto out;
 			}
 
-			names = reftable_calloc(sizeof(char *));
+			REFTABLE_CALLOC_ARRAY(names, 1);
 		} else {
 			err = fd_read_lines(fd, &names);
 			if (err < 0)
@@ -686,7 +684,7 @@ int reftable_stack_new_addition(struct reftable_addition **dest,
 {
 	int err = 0;
 	struct reftable_addition empty = REFTABLE_ADDITION_INIT;
-	*dest = reftable_calloc(sizeof(**dest));
+	REFTABLE_CALLOC_ARRAY(*dest, 1);
 	**dest = empty;
 	err = reftable_stack_init_addition(*dest, st);
 	if (err) {
@@ -871,7 +869,7 @@ static int stack_write_compact(struct reftable_stack *st,
 {
 	int subtabs_len = last - first + 1;
 	struct reftable_table *subtabs = reftable_calloc(
-		sizeof(struct reftable_table) * (last - first + 1));
+		last - first + 1, sizeof(*subtabs));
 	struct reftable_merged_table *mt = NULL;
 	int err = 0;
 	struct reftable_iterator it = { NULL };
@@ -979,9 +977,9 @@ static int stack_compact_range(struct reftable_stack *st, int first, int last,
 	int compact_count = last - first + 1;
 	char **listp = NULL;
 	char **delete_on_success =
-		reftable_calloc(sizeof(char *) * (compact_count + 1));
+		reftable_calloc(compact_count + 1, sizeof(*delete_on_success));
 	char **subtable_locks =
-		reftable_calloc(sizeof(char *) * (compact_count + 1));
+		reftable_calloc(compact_count + 1, sizeof(*subtable_locks));
 	int i = 0;
 	int j = 0;
 	int is_empty_table = 0;
@@ -1204,7 +1202,7 @@ int fastlog2(uint64_t sz)
 
 struct segment *sizes_to_segments(int *seglen, uint64_t *sizes, int n)
 {
-	struct segment *segs = reftable_calloc(sizeof(struct segment) * n);
+	struct segment *segs = reftable_calloc(n, sizeof(*segs));
 	int next = 0;
 	struct segment cur = { 0 };
 	int i = 0;
@@ -1268,7 +1266,7 @@ struct segment suggest_compaction_segment(uint64_t *sizes, int n)
 static uint64_t *stack_table_sizes_for_compaction(struct reftable_stack *st)
 {
 	uint64_t *sizes =
-		reftable_calloc(sizeof(uint64_t) * st->merged->stack_len);
+		reftable_calloc(st->merged->stack_len, sizeof(*sizes));
 	int version = (st->config.hash_id == GIT_SHA1_FORMAT_ID) ? 1 : 2;
 	int overhead = header_size(version) - 1;
 	int i = 0;
diff --git a/reftable/tree.c b/reftable/tree.c
index a5bf880985..528f33ae38 100644
--- a/reftable/tree.c
+++ b/reftable/tree.c
@@ -20,8 +20,8 @@ struct tree_node *tree_search(void *key, struct tree_node **rootp,
 		if (!insert) {
 			return NULL;
 		} else {
-			struct tree_node *n =
-				reftable_calloc(sizeof(struct tree_node));
+			struct tree_node *n;
+			REFTABLE_CALLOC_ARRAY(n, 1);
 			n->key = key;
 			*rootp = n;
 			return *rootp;
diff --git a/reftable/writer.c b/reftable/writer.c
index 4483bb21c3..47b3448132 100644
--- a/reftable/writer.c
+++ b/reftable/writer.c
@@ -49,7 +49,7 @@ static int padded_write(struct reftable_writer *w, uint8_t *data, size_t len,
 {
 	int n = 0;
 	if (w->pending_padding > 0) {
-		uint8_t *zeroed = reftable_calloc(w->pending_padding);
+		uint8_t *zeroed = reftable_calloc(w->pending_padding, sizeof(*zeroed));
 		int n = w->write(w->write_arg, zeroed, w->pending_padding);
 		if (n < 0)
 			return n;
@@ -123,8 +123,7 @@ struct reftable_writer *
 reftable_new_writer(ssize_t (*writer_func)(void *, const void *, size_t),
 		    void *writer_arg, struct reftable_write_options *opts)
 {
-	struct reftable_writer *wp =
-		reftable_calloc(sizeof(struct reftable_writer));
+	struct reftable_writer *wp = reftable_calloc(1, sizeof(*wp));
 	strbuf_init(&wp->block_writer_data.last_key, 0);
 	options_set_defaults(opts);
 	if (opts->block_size >= (1 << 24)) {
@@ -132,7 +131,7 @@ reftable_new_writer(ssize_t (*writer_func)(void *, const void *, size_t),
 		abort();
 	}
 	wp->last_key = reftable_empty_strbuf;
-	wp->block = reftable_calloc(opts->block_size);
+	REFTABLE_CALLOC_ARRAY(wp->block, opts->block_size);
 	wp->write = writer_func;
 	wp->write_arg = writer_arg;
 	wp->opts = *opts;
