diff --git a/include/bitcoin/system/arena.hpp b/include/bitcoin/system/arena.hpp
index 557be4f0d7..19e175112f 100644
--- a/include/bitcoin/system/arena.hpp
+++ b/include/bitcoin/system/arena.hpp
@@ -51,10 +51,17 @@ class arena
         return do_is_equal(other);
     }
 
+    /// Get the remaining area memory capacity (additional to std::pmr).
+    NODISCARD size_t get_capacity() const NOEXCEPT
+    {
+        return do_get_capacity();
+    }
+
 private:
     virtual void* do_allocate(size_t bytes, size_t align) THROWS = 0;
     virtual void do_deallocate(void* ptr, size_t bytes, size_t align) NOEXCEPT = 0;
     virtual bool do_is_equal(const arena& other) const NOEXCEPT = 0;
+    virtual size_t do_get_capacity() const NOEXCEPT = 0;
 };
 
 /// Left can deallocate memory allocated by right and vice versa.
@@ -84,6 +91,7 @@ class BC_API default_arena final
     void* do_allocate(size_t bytes, size_t align) THROWS override;
     void do_deallocate(void* ptr, size_t bytes, size_t align) NOEXCEPT override;
     bool do_is_equal(const arena& other) const NOEXCEPT override;
+    size_t do_get_capacity() const NOEXCEPT override;
 };
 
 } // namespace libbitcoin
diff --git a/src/arena.cpp b/src/arena.cpp
index b922f73b4a..95e6c088f2 100644
--- a/src/arena.cpp
+++ b/src/arena.cpp
@@ -18,6 +18,8 @@
  */
 #include <bitcoin/system/arena.hpp>
 
+#include <bitcoin/system/constants.hpp>
+
 namespace libbitcoin {
 
 BC_PUSH_WARNING(NO_NEW_OR_DELETE)
@@ -27,6 +29,14 @@ bool operator==(const arena& left, const arena& right) NOEXCEPT
     return &left == &right || left.is_equal(right);
 }
 
+// static
+// use bc::default_arena::get() vs. std::pmr::get_default_resource()
+arena* default_arena::get() NOEXCEPT
+{
+    static default_arena resource{};
+    return &resource;
+}
+
 void* default_arena::do_allocate(size_t bytes, size_t) THROWS
 {
     ////if (align > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
@@ -49,11 +59,9 @@ bool default_arena::do_is_equal(const arena& other) const NOEXCEPT
     return &other == this;
 }
 
-// use bc::default_arena::get() vs. std::pmr::get_default_resource()
-arena* default_arena::get() NOEXCEPT
+size_t default_arena::do_get_capacity() const NOEXCEPT
 {
-    static default_arena resource{};
-    return &resource;
+    return max_size_t;
 }
 
 BC_POP_WARNING()
diff --git a/test/test.hpp b/test/test.hpp
index b262350faf..49ba03031e 100644
--- a/test/test.hpp
+++ b/test/test.hpp
@@ -157,6 +157,11 @@ class reporting_arena
         return &other == this;
     }
 
+    size_t do_get_capacity() const NOEXCEPT override
+    {
+        return {};
+    }
+
     void report(void* ptr, size_t bytes, bool allocate) const NOEXCEPT
     {
         if constexpr (Report)
@@ -204,6 +209,11 @@ class mock_arena
         do_is_equal_address = &other;
         return false;
     }
+
+    size_t do_get_capacity() const NOEXCEPT override
+    {
+        return {};
+    }
 };
 
 template <bool Report = false>