diff --git a/Marlin/src/MarlinCore.cpp b/Marlin/src/MarlinCore.cpp
index da3c6cbaa2..d05c9c6014 100644
--- a/Marlin/src/MarlinCore.cpp
+++ b/Marlin/src/MarlinCore.cpp
@@ -227,7 +227,7 @@ bool wait_for_heatup = true;
 
 // Inactivity shutdown
 millis_t max_inactive_time, // = 0
-         stepper_inactive_time = (DEFAULT_STEPPER_DEACTIVE_TIME) * 1000UL;
+         stepper_inactive_time = SEC_TO_MS(DEFAULT_STEPPER_DEACTIVE_TIME);
 
 #if PIN_EXISTS(CHDK)
   extern millis_t chdk_timeout;
@@ -543,7 +543,7 @@ inline void manage_inactivity(const bool ignore_stepper_queue=false) {
 
   #if ENABLED(EXTRUDER_RUNOUT_PREVENT)
     if (thermalManager.degHotend(active_extruder) > EXTRUDER_RUNOUT_MINTEMP
-      && ELAPSED(ms, gcode.previous_move_ms + (EXTRUDER_RUNOUT_SECONDS) * 1000UL)
+      && ELAPSED(ms, gcode.previous_move_ms + SEC_TO_MS(EXTRUDER_RUNOUT_SECONDS))
       && !planner.has_blocks_queued()
     ) {
       #if ENABLED(SWITCHING_EXTRUDER)
diff --git a/Marlin/src/core/millis_t.h b/Marlin/src/core/millis_t.h
index 39ea17b9f0..bf0b0bb308 100644
--- a/Marlin/src/core/millis_t.h
+++ b/Marlin/src/core/millis_t.h
@@ -25,5 +25,9 @@
 
 typedef uint32_t millis_t;
 
+#define SEC_TO_MS(N) millis_t((N)*1000UL)
+#define MIN_TO_MS(N) SEC_TO_MS((N)*60UL)
+#define MS_TO_SEC(N) millis_t((N)/1000UL)
+
 #define PENDING(NOW,SOON) ((int32_t)(NOW-(SOON))<0)
 #define ELAPSED(NOW,SOON) (!PENDING(NOW,SOON))
diff --git a/Marlin/src/feature/controllerfan.cpp b/Marlin/src/feature/controllerfan.cpp
index 0746700407..debfdea1f9 100644
--- a/Marlin/src/feature/controllerfan.cpp
+++ b/Marlin/src/feature/controllerfan.cpp
@@ -91,7 +91,7 @@ void ControllerFan::update() {
     //  - If AutoMode is on and steppers have been enabled for CONTROLLERFAN_IDLE_TIME seconds.
     //  - If System is on idle and idle fan speed settings is activated.
     set_fan_speed(
-      settings.auto_mode && lastMotorOn && PENDING(ms, lastMotorOn + settings.duration * 1000UL)
+      settings.auto_mode && lastMotorOn && PENDING(ms, lastMotorOn + SEC_TO_MS(settings.duration))
       ? settings.active_speed : settings.idle_speed
     );
 
diff --git a/Marlin/src/feature/pause.cpp b/Marlin/src/feature/pause.cpp
index 23fa2fee01..259b130822 100644
--- a/Marlin/src/feature/pause.cpp
+++ b/Marlin/src/feature/pause.cpp
@@ -485,7 +485,7 @@ void wait_for_confirmation(const bool is_reload/*=false*/, const int8_t max_beep
   #endif
 
   // Start the heater idle timers
-  const millis_t nozzle_timeout = (millis_t)(PAUSE_PARK_NOZZLE_TIMEOUT) * 1000UL;
+  const millis_t nozzle_timeout = SEC_TO_MS(PAUSE_PARK_NOZZLE_TIMEOUT);
 
   HOTEND_LOOP() thermalManager.hotend_idle[e].start(nozzle_timeout);
 
@@ -549,7 +549,7 @@ void wait_for_confirmation(const bool is_reload/*=false*/, const int8_t max_beep
       show_continue_prompt(is_reload);
 
       // Start the heater idle timers
-      const millis_t nozzle_timeout = (millis_t)(PAUSE_PARK_NOZZLE_TIMEOUT) * 1000UL;
+      const millis_t nozzle_timeout = SEC_TO_MS(PAUSE_PARK_NOZZLE_TIMEOUT);
 
       HOTEND_LOOP() thermalManager.hotend_idle[e].start(nozzle_timeout);
       #if ENABLED(HOST_PROMPT_SUPPORT)
diff --git a/Marlin/src/feature/power.cpp b/Marlin/src/feature/power.cpp
index 1fa751811e..510747d208 100644
--- a/Marlin/src/feature/power.cpp
+++ b/Marlin/src/feature/power.cpp
@@ -98,7 +98,7 @@ void Power::check() {
     nextPowerCheck = ms + 2500UL;
     if (is_power_needed())
       power_on();
-    else if (!lastPowerOn || ELAPSED(ms, lastPowerOn + (POWER_TIMEOUT) * 1000UL))
+    else if (!lastPowerOn || ELAPSED(ms, lastPowerOn + SEC_TO_MS(POWER_TIMEOUT)))
       power_off();
   }
 }
diff --git a/Marlin/src/gcode/calibrate/G76_M871.cpp b/Marlin/src/gcode/calibrate/G76_M871.cpp
index c878f83a17..4bc27b82f5 100644
--- a/Marlin/src/gcode/calibrate/G76_M871.cpp
+++ b/Marlin/src/gcode/calibrate/G76_M871.cpp
@@ -182,7 +182,7 @@ void GcodeSuite::G76() {
       do_blocking_move_to(parkpos);
 
       // Wait for heatbed to reach target temp and probe to cool below target temp
-      if (wait_for_temps(target_bed, target_probe, next_temp_report, millis() + 900UL * 1000UL)) {
+      if (wait_for_temps(target_bed, target_probe, next_temp_report, millis() + MIN_TO_MS(15))) {
         SERIAL_ECHOLNPGM("!Bed heating timeout.");
         break;
       }
diff --git a/Marlin/src/gcode/gcode.cpp b/Marlin/src/gcode/gcode.cpp
index 0937a86bd2..57abc37b0d 100644
--- a/Marlin/src/gcode/gcode.cpp
+++ b/Marlin/src/gcode/gcode.cpp
@@ -988,7 +988,7 @@ void GcodeSuite::process_subcommands_now(char * gcode) {
           break;
       }
     }
-    next_busy_signal_ms = ms + host_keepalive_interval * 1000UL;
+    next_busy_signal_ms = ms + SEC_TO_MS(host_keepalive_interval);
   }
 
 #endif // HOST_KEEPALIVE_FEATURE
diff --git a/Marlin/src/libs/stopwatch.cpp b/Marlin/src/libs/stopwatch.cpp
index 6b01158cb9..c75eb2da09 100644
--- a/Marlin/src/libs/stopwatch.cpp
+++ b/Marlin/src/libs/stopwatch.cpp
@@ -106,8 +106,7 @@ void Stopwatch::reset() {
 }
 
 millis_t Stopwatch::duration() {
-  return ((isRunning() ? millis() : stopTimestamp)
-          - startTimestamp) / 1000UL + accumulator;
+  return accumulator + MS_TO_SEC((isRunning() ? millis() : stopTimestamp) - startTimestamp);
 }
 
 #if ENABLED(DEBUG_STOPWATCH)
diff --git a/Marlin/src/module/temperature.cpp b/Marlin/src/module/temperature.cpp
index af2f1a10e8..f9f311635e 100644
--- a/Marlin/src/module/temperature.cpp
+++ b/Marlin/src/module/temperature.cpp
@@ -399,7 +399,7 @@ volatile bool Temperature::raw_temps_ready = false;
       const uint16_t watch_temp_period = GTV(WATCH_BED_TEMP_PERIOD, WATCH_TEMP_PERIOD);
       const uint8_t watch_temp_increase = GTV(WATCH_BED_TEMP_INCREASE, WATCH_TEMP_INCREASE);
       const float watch_temp_target = target - float(watch_temp_increase + GTV(TEMP_BED_HYSTERESIS, TEMP_HYSTERESIS) + 1);
-      millis_t temp_change_ms = next_temp_ms + watch_temp_period * 1000UL;
+      millis_t temp_change_ms = next_temp_ms + SEC_TO_MS(watch_temp_period);
       float next_watch_temp = 0.0;
       bool heated = false;
     #endif
@@ -546,7 +546,7 @@ volatile bool Temperature::raw_temps_ready = false;
             if (!heated) {                                            // If not yet reached target...
               if (current_temp > next_watch_temp) {                   // Over the watch temp?
                 next_watch_temp = current_temp + watch_temp_increase; // - set the next temp to watch for
-                temp_change_ms = ms + watch_temp_period * 1000UL;     // - move the expiration timer up
+                temp_change_ms = ms + SEC_TO_MS(watch_temp_period);     // - move the expiration timer up
                 if (current_temp > watch_temp_target) heated = true;  // - Flag if target temperature reached
               }
               else if (ELAPSED(ms, temp_change_ms))                   // Watch timer expired
@@ -2051,7 +2051,7 @@ void Temperature::init() {
         #endif
 
         if (current >= tr_target_temperature[heater_index] - hysteresis_degc) {
-          sm.timer = millis() + period_seconds * 1000UL;
+          sm.timer = millis() + SEC_TO_MS(period_seconds);
           break;
         }
         else if (PENDING(millis(), sm.timer)) break;
@@ -3124,7 +3124,7 @@ void Temperature::tick() {
         millis_t residency_start_ms = 0;
         bool first_loop = true;
         // Loop until the temperature has stabilized
-        #define TEMP_CONDITIONS (!residency_start_ms || PENDING(now, residency_start_ms + (TEMP_RESIDENCY_TIME) * 1000UL))
+        #define TEMP_CONDITIONS (!residency_start_ms || PENDING(now, residency_start_ms + SEC_TO_MS(TEMP_RESIDENCY_TIME)))
       #else
         // Loop until the temperature is very close target
         #define TEMP_CONDITIONS (wants_to_cool ? isCoolingHotend(target_extruder) : isHeatingHotend(target_extruder))
@@ -3160,7 +3160,7 @@ void Temperature::tick() {
           #if TEMP_RESIDENCY_TIME > 0
             SERIAL_ECHOPGM(" W:");
             if (residency_start_ms)
-              SERIAL_ECHO(long((((TEMP_RESIDENCY_TIME) * 1000UL) - (now - residency_start_ms)) / 1000UL));
+              SERIAL_ECHO(long((SEC_TO_MS(TEMP_RESIDENCY_TIME) - (now - residency_start_ms)) / 1000UL));
             else
               SERIAL_CHAR('?');
           #endif
@@ -3185,7 +3185,7 @@ void Temperature::tick() {
             // Start the TEMP_RESIDENCY_TIME timer when we reach target temp for the first time.
             if (temp_diff < TEMP_WINDOW) {
               residency_start_ms = now;
-              if (first_loop) residency_start_ms += (TEMP_RESIDENCY_TIME) * 1000UL;
+              if (first_loop) residency_start_ms += SEC_TO_MS(TEMP_RESIDENCY_TIME);
             }
           }
           else if (temp_diff > TEMP_HYSTERESIS) {
@@ -3247,7 +3247,7 @@ void Temperature::tick() {
         millis_t residency_start_ms = 0;
         bool first_loop = true;
         // Loop until the temperature has stabilized
-        #define TEMP_BED_CONDITIONS (!residency_start_ms || PENDING(now, residency_start_ms + (TEMP_BED_RESIDENCY_TIME) * 1000UL))
+        #define TEMP_BED_CONDITIONS (!residency_start_ms || PENDING(now, residency_start_ms + SEC_TO_MS(TEMP_BED_RESIDENCY_TIME)))
       #else
         // Loop until the temperature is very close target
         #define TEMP_BED_CONDITIONS (wants_to_cool ? isCoolingBed() : isHeatingBed())
@@ -3284,7 +3284,7 @@ void Temperature::tick() {
           #if TEMP_BED_RESIDENCY_TIME > 0
             SERIAL_ECHOPGM(" W:");
             if (residency_start_ms)
-              SERIAL_ECHO(long((((TEMP_BED_RESIDENCY_TIME) * 1000UL) - (now - residency_start_ms)) / 1000UL));
+              SERIAL_ECHO(long((SEC_TO_MS(TEMP_BED_RESIDENCY_TIME) - (now - residency_start_ms)) / 1000UL));
             else
               SERIAL_CHAR('?');
           #endif
@@ -3309,7 +3309,7 @@ void Temperature::tick() {
             // Start the TEMP_BED_RESIDENCY_TIME timer when we reach target temp for the first time.
             if (temp_diff < TEMP_BED_WINDOW) {
               residency_start_ms = now;
-              if (first_loop) residency_start_ms += (TEMP_BED_RESIDENCY_TIME) * 1000UL;
+              if (first_loop) residency_start_ms += SEC_TO_MS(TEMP_BED_RESIDENCY_TIME);
             }
           }
           else if (temp_diff > TEMP_BED_HYSTERESIS) {
@@ -3373,7 +3373,7 @@ void Temperature::tick() {
         millis_t residency_start_ms = 0;
         bool first_loop = true;
         // Loop until the temperature has stabilized
-        #define TEMP_CHAMBER_CONDITIONS (!residency_start_ms || PENDING(now, residency_start_ms + (TEMP_CHAMBER_RESIDENCY_TIME) * 1000UL))
+        #define TEMP_CHAMBER_CONDITIONS (!residency_start_ms || PENDING(now, residency_start_ms + SEC_TO_MS(TEMP_CHAMBER_RESIDENCY_TIME)))
       #else
         // Loop until the temperature is very close target
         #define TEMP_CHAMBER_CONDITIONS (wants_to_cool ? isCoolingChamber() : isHeatingChamber())
@@ -3405,7 +3405,7 @@ void Temperature::tick() {
           #if TEMP_CHAMBER_RESIDENCY_TIME > 0
             SERIAL_ECHOPGM(" W:");
             if (residency_start_ms)
-              SERIAL_ECHO(long((((TEMP_CHAMBER_RESIDENCY_TIME) * 1000UL) - (now - residency_start_ms)) / 1000UL));
+              SERIAL_ECHO(long((SEC_TO_MS(TEMP_CHAMBER_RESIDENCY_TIME) - (now - residency_start_ms)) / 1000UL));
             else
               SERIAL_CHAR('?');
           #endif
@@ -3425,7 +3425,7 @@ void Temperature::tick() {
             // Start the TEMP_CHAMBER_RESIDENCY_TIME timer when we reach target temp for the first time.
             if (temp_diff < TEMP_CHAMBER_WINDOW) {
               residency_start_ms = now;
-              if (first_loop) residency_start_ms += (TEMP_CHAMBER_RESIDENCY_TIME) * 1000UL;
+              if (first_loop) residency_start_ms += SEC_TO_MS(TEMP_CHAMBER_RESIDENCY_TIME);
             }
           }
           else if (temp_diff > TEMP_CHAMBER_HYSTERESIS) {
diff --git a/Marlin/src/module/temperature.h b/Marlin/src/module/temperature.h
index 24e0054496..cba1642afd 100644
--- a/Marlin/src/module/temperature.h
+++ b/Marlin/src/module/temperature.h
@@ -241,7 +241,7 @@ struct HeaterWatch {
       const int16_t newtarget = curr + INCREASE;
       if (newtarget < tgt - HYSTERESIS - 1) {
         target = newtarget;
-        next_ms = millis() + PERIOD * 1000UL;
+        next_ms = millis() + SEC_TO_MS(PERIOD);
         return;
       }
     }