diff --git a/src/display.cpp b/src/display.cpp
index 11045650ead..c5449fe9370 100644
--- a/src/display.cpp
+++ b/src/display.cpp
@@ -42,6 +42,7 @@
 #include "play_controller.hpp" //note: this can probably be refactored out
 #include "reports.hpp"
 #include "resources.hpp"
+#include "serialization/chrono.hpp"
 #include "synced_context.hpp"
 #include "team.hpp"
 #include "terrain/builder.hpp"
@@ -1929,7 +1930,7 @@ void display::scroll_to_xy(const point& screen_coordinates, SCROLL_TYPE scroll_t
 		events::pump();
 
 		auto time = std::chrono::steady_clock::now();
-		auto dt = std::chrono::duration_cast<fractional_seconds>(time - prev_time);
+		auto dt = fractional_seconds{time - prev_time};
 
 		// Do not skip too many frames on slow PCs
 		dt = std::min<fractional_seconds>(dt, 200ms);
@@ -2208,8 +2209,7 @@ void display::fade_tod_mask(
 	auto duration = 300ms / turbo_speed();
 	auto start = std::chrono::steady_clock::now();
 	for(auto now = start; now < start + duration; now = std::chrono::steady_clock::now()) {
-		float prop_f = float((now - start).count()) / float(duration.count());
-		uint8_t p = float_to_color(prop_f);
+		uint8_t p = float_to_color(chrono::normalize_progress(now - start, duration));
 		tod_hex_alpha2 = p;
 		tod_hex_alpha1 = ~p;
 		draw_manager::invalidate_region(map_outside_area());
@@ -2242,8 +2242,7 @@ void display::fade_to(const color_t& c, const std::chrono::milliseconds& duratio
 
 	// Smoothly blend and display
 	for(auto now = start; now < start + duration; now = std::chrono::steady_clock::now()) {
-		float prop_f = float((now - start).count()) / float(duration.count());
-		uint8_t p = float_to_color(prop_f);
+		uint8_t p = float_to_color(chrono::normalize_progress(now - start, duration));
 		fade_color_ = fade_start.smooth_blend(fade_end, p);
 		draw_manager::invalidate_region(map_outside_area());
 		events::pump_and_draw();
diff --git a/src/gui/dialogs/outro.cpp b/src/gui/dialogs/outro.cpp
index 8bac44dd1a8..bae05b4c0c8 100644
--- a/src/gui/dialogs/outro.cpp
+++ b/src/gui/dialogs/outro.cpp
@@ -22,6 +22,7 @@
 #include "game_classification.hpp"
 #include "gettext.hpp"
 #include "gui/widgets/window.hpp"
+#include "serialization/chrono.hpp"
 #include "serialization/markup.hpp"
 
 #include <cmath>
@@ -130,7 +131,7 @@ void outro::update()
 	switch(stage_) {
 	case stage::fading_in:
 		if(now <= stage_start_ + fade_duration) {
-			window_canvas.set_variable("fade_alpha", wfl::variant(255.0 * get_fade_progress(now)));
+			window_canvas.set_variable("fade_alpha", wfl::variant(float_to_color(get_fade_progress(now))));
 		} else {
 			goto_stage(stage::waiting);
 		}
@@ -146,7 +147,7 @@ void outro::update()
 
 	case stage::fading_out:
 		if(now <= stage_start_ + fade_duration) {
-			window_canvas.set_variable("fade_alpha", wfl::variant(255.0 * (1.0 - get_fade_progress(now))));
+			window_canvas.set_variable("fade_alpha", wfl::variant(float_to_color(1.0 - get_fade_progress(now))));
 		} else if(++text_index_ < text_.size()) {
 			window_canvas.set_variable("outro_text", wfl::variant(text_[text_index_]));
 			goto_stage(stage::fading_in);
@@ -165,9 +166,7 @@ void outro::update()
 
 double outro::get_fade_progress(const std::chrono::steady_clock::time_point& now) const
 {
-	using fractional_milliseconds = std::chrono::duration<double, std::milli>;
-	const auto time = fractional_milliseconds{now - stage_start_} / fade_duration;
-	return std::clamp(time, 0.0, 1.0);
+	return chrono::normalize_progress(now - stage_start_, fade_duration);
 }
 
 } // namespace dialogs
diff --git a/src/serialization/chrono.hpp b/src/serialization/chrono.hpp
index 4311523642e..24415a3fc33 100644
--- a/src/serialization/chrono.hpp
+++ b/src/serialization/chrono.hpp
@@ -16,6 +16,7 @@
 
 #include "config_attribute_value.hpp"
 
+#include <algorithm>
 #include <chrono>
 #include <iomanip>
 #include <sstream>
@@ -72,6 +73,14 @@ inline auto parse_duration(const config_attribute_value& val, const Duration& de
 	return Duration{val.to_long_long(def.count())};
 }
 
+template<typename RepE, typename PeriodE, typename RepD, typename PeriodD>
+constexpr double normalize_progress(
+	const std::chrono::duration<RepE, PeriodE>& elapsed,
+	const std::chrono::duration<RepD, PeriodD>& duration)
+{
+	return std::clamp(std::chrono::duration<double, PeriodE>{elapsed} / duration, 0.0, 1.0);
+}
+
 template<typename... Ts, typename Rep, typename Period>
 constexpr auto deconstruct_duration(const std::tuple<Ts...>&, const std::chrono::duration<Rep, Period>& span)
 {