diff --git a/src/common/system.cpp b/src/common/system.cpp
index 72e9de100be..98bc01471d5 100644
--- a/src/common/system.cpp
+++ b/src/common/system.cpp
@@ -37,9 +37,6 @@
 
 using util::ReplaceAll;
 
-// Application startup time (used for uptime calculation)
-const int64_t nStartupTime = GetTime();
-
 #ifndef WIN32
 std::string ShellEscape(const std::string& arg)
 {
@@ -130,8 +127,8 @@ std::optional<size_t> GetTotalRAM()
     return std::nullopt;
 }
 
-// Obtain the application startup time (used for uptime calculation)
-int64_t GetStartupTime()
+SteadyClock::duration GetUptime()
 {
-    return nStartupTime;
+    static const auto g_startup_time{SteadyClock::now()};
+    return SteadyClock::now() - g_startup_time;
 }
diff --git a/src/common/system.h b/src/common/system.h
index 2184f1d4c9e..a3100fecbc1 100644
--- a/src/common/system.h
+++ b/src/common/system.h
@@ -7,13 +7,15 @@
 #define BITCOIN_COMMON_SYSTEM_H
 
 #include <bitcoin-build-config.h> // IWYU pragma: keep
+#include <util/time.h>
 
+#include <chrono>
 #include <cstdint>
 #include <optional>
 #include <string>
 
-// Application startup time (used for uptime calculation)
-int64_t GetStartupTime();
+/// Monotonic uptime (not affected by system time changes).
+SteadyClock::duration GetUptime();
 
 void SetupEnvironment();
 [[nodiscard]] bool SetupNetworking();
diff --git a/src/qt/clientmodel.cpp b/src/qt/clientmodel.cpp
index dda26fa059b..cd7d9e32587 100644
--- a/src/qt/clientmodel.cpp
+++ b/src/qt/clientmodel.cpp
@@ -210,7 +210,7 @@ bool ClientModel::isReleaseVersion() const
 
 QString ClientModel::formatClientStartupTime() const
 {
-    return QDateTime::fromSecsSinceEpoch(GetStartupTime()).toString();
+    return QDateTime::currentDateTime().addSecs(-TicksSeconds(GetUptime())).toString();
 }
 
 QString ClientModel::dataDir() const
diff --git a/src/rpc/server.cpp b/src/rpc/server.cpp
index 5fd733d056b..01fb815a967 100644
--- a/src/rpc/server.cpp
+++ b/src/rpc/server.cpp
@@ -184,7 +184,7 @@ static RPCHelpMan uptime()
                 },
         [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
 {
-    return GetTime() - GetStartupTime();
+    return TicksSeconds(GetUptime());
 }
     };
 }
diff --git a/src/test/util_tests.cpp b/src/test/util_tests.cpp
index eb6057a6ffb..2b4e5330e9e 100644
--- a/src/test/util_tests.cpp
+++ b/src/test/util_tests.cpp
@@ -600,6 +600,15 @@ BOOST_AUTO_TEST_CASE(util_mocktime)
     SetMockTime(0s);
 }
 
+BOOST_AUTO_TEST_CASE(util_ticksseconds)
+{
+    BOOST_CHECK_EQUAL(TicksSeconds(0s), 0);
+    BOOST_CHECK_EQUAL(TicksSeconds(1s), 1);
+    BOOST_CHECK_EQUAL(TicksSeconds(999ms), 0);
+    BOOST_CHECK_EQUAL(TicksSeconds(1000ms), 1);
+    BOOST_CHECK_EQUAL(TicksSeconds(1500ms), 1);
+}
+
 BOOST_AUTO_TEST_CASE(test_IsDigit)
 {
     BOOST_CHECK_EQUAL(IsDigit('0'), true);
diff --git a/src/util/time.h b/src/util/time.h
index 0f98726d224..59abc4d5a7f 100644
--- a/src/util/time.h
+++ b/src/util/time.h
@@ -74,6 +74,12 @@ constexpr auto Ticks(Dur2 d)
 {
     return std::chrono::duration_cast<Dur1>(d).count();
 }
+
+template <typename Duration>
+constexpr int64_t TicksSeconds(Duration d)
+{
+    return int64_t{Ticks<std::chrono::seconds>(d)};
+}
 template <typename Duration, typename Timepoint>
 constexpr auto TicksSinceEpoch(Timepoint t)
 {
diff --git a/test/functional/rpc_uptime.py b/test/functional/rpc_uptime.py
index 74880417941..817ba2b4b53 100755
--- a/test/functional/rpc_uptime.py
+++ b/test/functional/rpc_uptime.py
@@ -26,9 +26,12 @@ class UptimeTest(BitcoinTestFramework):
         assert_raises_rpc_error(-8, "Mocktime must be in the range [0, 9223372036], not -1.", self.nodes[0].setmocktime, -1)
 
     def _test_uptime(self):
-        wait_time = 10
-        self.nodes[0].setmocktime(int(time.time() + wait_time))
-        assert self.nodes[0].uptime() >= wait_time
+        wait_time = 20_000
+        uptime_before = self.nodes[0].uptime()
+        self.nodes[0].setmocktime(int(time.time()) + wait_time)
+        uptime_after = self.nodes[0].uptime()
+        self.nodes[0].setmocktime(0)
+        assert uptime_after - uptime_before < wait_time, "uptime should not jump with wall clock"
 
 
 if __name__ == '__main__':