diff --git a/src/init.cpp b/src/init.cpp
index 2f7c6588b85c2..090a11a825d38 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -1631,10 +1631,11 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
 
     // On first startup, warn on low block storage space
     if (!fReindex && !fReindexChainState && chain_active_height <= 1) {
+        uint64_t assumed_chain_bytes{chainparams.AssumedBlockchainSize() * 1024 * 1024 * 1024};
         uint64_t additional_bytes_needed{
             chainman.m_blockman.IsPruneMode() ?
-                chainman.m_blockman.GetPruneTarget() :
-                chainparams.AssumedBlockchainSize() * 1024 * 1024 * 1024};
+                std::min(chainman.m_blockman.GetPruneTarget(), assumed_chain_bytes) :
+                assumed_chain_bytes};
 
         if (!CheckDiskSpace(args.GetBlocksDirPath(), additional_bytes_needed)) {
             InitWarning(strprintf(_(
diff --git a/test/functional/rpc_blockchain.py b/test/functional/rpc_blockchain.py
index 7a0cedb1f58cb..6022042c1167b 100755
--- a/test/functional/rpc_blockchain.py
+++ b/test/functional/rpc_blockchain.py
@@ -69,6 +69,7 @@ def set_test_params(self):
 
     def run_test(self):
         self.wallet = MiniWallet(self.nodes[0])
+        self._test_prune_disk_space()
         self.mine_chain()
         self._test_max_future_block_time()
         self.restart_node(
@@ -100,6 +101,13 @@ def mine_chain(self):
             self.generate(self.wallet, 1)
         assert_equal(self.nodes[0].getblockchaininfo()['blocks'], HEIGHT)
 
+    def _test_prune_disk_space(self):
+        self.log.info("Test that a manually pruned node does not run into "
+                      "integer overflow on first start up")
+        self.restart_node(0, extra_args=["-prune=1"])
+        self.log.info("Avoid warning when assumed chain size is enough")
+        self.restart_node(0, extra_args=["-prune=123456789"])
+
     def _test_max_future_block_time(self):
         self.stop_node(0)
         self.log.info("A block tip of more than MAX_FUTURE_BLOCK_TIME in the future raises an error")