diff --git a/src/kernel/bitcoinkernel.cpp b/src/kernel/bitcoinkernel.cpp
index dc03be71461..4ba60c1b56c 100644
--- a/src/kernel/bitcoinkernel.cpp
+++ b/src/kernel/bitcoinkernel.cpp
@@ -1352,13 +1352,13 @@ const btck_Chain* btck_chainstate_manager_get_active_chain(const btck_Chainstate
     return btck_Chain::ref(&WITH_LOCK(btck_ChainstateManager::get(chainman).m_chainman->GetMutex(), return btck_ChainstateManager::get(chainman).m_chainman->ActiveChain()));
 }
 
-int btck_chain_get_height(const btck_Chain* chain)
+int32_t btck_chain_get_height(const btck_Chain* chain)
 {
     LOCK(::cs_main);
     return btck_Chain::get(chain).Height();
 }
 
-const btck_BlockTreeEntry* btck_chain_get_by_height(const btck_Chain* chain, int height)
+const btck_BlockTreeEntry* btck_chain_get_by_height(const btck_Chain* chain, int32_t height)
 {
     LOCK(::cs_main);
     return btck_BlockTreeEntry::ref(btck_Chain::get(chain)[height]);
diff --git a/src/kernel/bitcoinkernel.h b/src/kernel/bitcoinkernel.h
index d3028b491d2..cd837573dff 100644
--- a/src/kernel/bitcoinkernel.h
+++ b/src/kernel/bitcoinkernel.h
@@ -112,6 +112,12 @@ extern "C" {
  * object.
  *
  * Array lengths follow the pointer argument they describe.
+ *
+ * @section types Type conventions
+ *
+ * Fixed-width integer types (e.g. int32_t, uint32_t) are used for data values
+ * such as heights. Plain int and unsigned int are used for boolean-like values
+ * and flags.
  */
 
 /**
@@ -1423,7 +1429,7 @@ BITCOINKERNEL_API int32_t BITCOINKERNEL_WARN_UNUSED_RESULT btck_chain_get_height
  */
 BITCOINKERNEL_API const btck_BlockTreeEntry* BITCOINKERNEL_WARN_UNUSED_RESULT btck_chain_get_by_height(
     const btck_Chain* chain,
-    int block_height) BITCOINKERNEL_ARG_NONNULL(1);
+    int32_t block_height) BITCOINKERNEL_ARG_NONNULL(1);
 
 /**
  * @brief Return true if the passed in chain contains the block tree entry.
diff --git a/src/kernel/bitcoinkernel_wrapper.h b/src/kernel/bitcoinkernel_wrapper.h
index cb7af8b35dd..38dd709f948 100644
--- a/src/kernel/bitcoinkernel_wrapper.h
+++ b/src/kernel/bitcoinkernel_wrapper.h
@@ -1122,12 +1122,12 @@ public:
         return btck_chain_get_height(get());
     }
 
-    int CountEntries() const
+    int32_t CountEntries() const
     {
         return btck_chain_get_height(get()) + 1;
     }
 
-    BlockTreeEntry GetByHeight(int height) const
+    BlockTreeEntry GetByHeight(int32_t height) const
     {
         auto index{btck_chain_get_by_height(get(), height)};
         if (!index) throw std::runtime_error("No entry in the chain at the provided height");