diff --git a/include/haproxy/htx-t.h b/include/haproxy/htx-t.h
index e49b0ee86..00703412d 100644
--- a/include/haproxy/htx-t.h
+++ b/include/haproxy/htx-t.h
@@ -187,10 +187,6 @@ struct htx_sl {
 
 	/* XXX 2 bytes unused */
 
-	int32_t hdrs_bytes;  /* Bytes held by all headers, as seen by the mux
-			      * during parsing, from this start-line to the
-			      * corresponding EOH. -1 if unknown */
-
 	unsigned int len[3]; /* length of different parts of the start-line */
 	char         l[VAR_ARRAY];
 };
diff --git a/include/haproxy/htx.h b/include/haproxy/htx.h
index 242397cbb..ce6b7853f 100644
--- a/include/haproxy/htx.h
+++ b/include/haproxy/htx.h
@@ -446,7 +446,6 @@ static inline struct htx_sl *htx_add_stline(struct htx *htx, enum htx_blk_type t
 	blk->info += size;
 
 	sl = htx_get_blk_ptr(htx, blk);
-	sl->hdrs_bytes = -1;
 	sl->flags = flags;
 
 	HTX_SL_P1_LEN(sl) = p1.len;
diff --git a/src/h1_htx.c b/src/h1_htx.c
index 136bf461e..dfc6b89c9 100644
--- a/src/h1_htx.c
+++ b/src/h1_htx.c
@@ -152,7 +152,6 @@ static int h1_postparse_req_hdrs(struct h1m *h1m, union h1_sl *h1sl, struct htx
 	struct htx_sl *sl;
 	struct ist meth, uri, vsn;
 	unsigned int flags;
-	size_t used;
 
 	/* <h1sl> is always defined for a request */
 	meth = h1sl->rq.m;
@@ -178,7 +177,6 @@ static int h1_postparse_req_hdrs(struct h1m *h1m, union h1_sl *h1sl, struct htx
 		h1m->curr_len = h1m->body_len = 0;
 	}
 
-	used = htx_used_space(htx);
 	flags = h1m_htx_sl_flags(h1m);
 	sl = htx_add_stline(htx, HTX_BLK_REQ_SL, flags, meth, uri, vsn);
 	if (!sl || !htx_add_all_headers(htx, hdrs))
@@ -194,8 +192,6 @@ static int h1_postparse_req_hdrs(struct h1m *h1m, union h1_sl *h1sl, struct htx
 		if (uri.len > 4 && (uri.ptr[0] | 0x20) == 'h')
 			sl->flags |= ((uri.ptr[4] == ':') ? HTX_SL_F_SCHM_HTTP : HTX_SL_F_SCHM_HTTPS);
 	}
-	/* Set bytes used in the HTX message for the headers now */
-	sl->hdrs_bytes = htx_used_space(htx) - used;
 
 	/* If body length cannot be determined, set htx->extra to
 	 * ULLONG_MAX. This value is impossible in other cases.
@@ -222,7 +218,6 @@ static int h1_postparse_res_hdrs(struct h1m *h1m, union h1_sl *h1sl, struct htx
 	struct htx_sl *sl;
 	struct ist vsn, status, reason;
 	unsigned int flags;
-	size_t used;
 	uint16_t code = 0;
 
 	if (h1sl) {
@@ -285,16 +280,12 @@ static int h1_postparse_res_hdrs(struct h1m *h1m, union h1_sl *h1sl, struct htx
 		h1m->flags |= H1_MF_XFER_LEN;
 	}
 
-	used = htx_used_space(htx);
 	flags = h1m_htx_sl_flags(h1m);
 	sl = htx_add_stline(htx, HTX_BLK_RES_SL, flags, vsn, status, reason);
 	if (!sl || !htx_add_all_headers(htx, hdrs))
 		goto error;
 	sl->info.res.status = code;
 
-	/* Set bytes used in the HTX message for the headers now */
-	sl->hdrs_bytes = htx_used_space(htx) - used;
-
 	/* If body length cannot be determined, set htx->extra to
 	 * ULLONG_MAX. This value is impossible in other cases.
 	 */
diff --git a/src/h2.c b/src/h2.c
index 9ff3c938e..27a7a4e90 100644
--- a/src/h2.c
+++ b/src/h2.c
@@ -369,7 +369,6 @@ int h2_make_htx_request(struct http_hdr *list, struct htx *htx, unsigned int *ms
 	int phdr;
 	int ret;
 	int i;
-	uint32_t used = htx_used_space(htx);
 	struct htx_sl *sl = NULL;
 	unsigned int sl_flags = 0;
 	const char *ctl;
@@ -554,9 +553,6 @@ int h2_make_htx_request(struct http_hdr *list, struct htx *htx, unsigned int *ms
 	if (!htx_add_endof(htx, HTX_BLK_EOH))
 		goto fail;
 
-	/* Set bytes used in the HTX message for the headers now */
-	sl->hdrs_bytes = htx_used_space(htx) - used;
-
 	ret = 1;
 	return ret;
 
@@ -670,7 +666,6 @@ int h2_make_htx_response(struct http_hdr *list, struct htx *htx, unsigned int *m
 	int phdr;
 	int ret;
 	int i;
-	uint32_t used = htx_used_space(htx);
 	struct htx_sl *sl = NULL;
 	unsigned int sl_flags = 0;
 	const char *ctl;
@@ -801,9 +796,6 @@ int h2_make_htx_response(struct http_hdr *list, struct htx *htx, unsigned int *m
 	if (!htx_add_endof(htx, HTX_BLK_EOH))
 		goto fail;
 
-	/* Set bytes used in the HTX message for the headers now */
-	sl->hdrs_bytes = htx_used_space(htx) - used;
-
 	ret = 1;
 	return ret;
 
diff --git a/src/htx.c b/src/htx.c
index 53646b903..28b2c47b6 100644
--- a/src/htx.c
+++ b/src/htx.c
@@ -808,7 +808,6 @@ struct htx_sl *htx_replace_stline(struct htx *htx, struct htx_blk *blk, const st
 	sl = htx_get_blk_ptr(htx, blk);
 	tmp.info = sl->info;
 	tmp.flags = sl->flags;
-	tmp.hdrs_bytes = sl->hdrs_bytes;
 
 	sz = htx_get_blksz(blk);
 	delta = sizeof(*sl) + p1.len + p2.len + p3.len - sz;
@@ -829,7 +828,6 @@ struct htx_sl *htx_replace_stline(struct htx *htx, struct htx_blk *blk, const st
 	sl = htx_get_blk_ptr(htx, blk);
 	sl->info = tmp.info;
 	sl->flags = tmp.flags;
-	sl->hdrs_bytes = tmp.hdrs_bytes;
 
 	HTX_SL_P1_LEN(sl) = p1.len;
 	HTX_SL_P2_LEN(sl) = p2.len;