diff --git a/src/_P005_DHT.ino b/src/_P005_DHT.ino
index d0d503e77..68315c259 100644
--- a/src/_P005_DHT.ino
+++ b/src/_P005_DHT.ino
@@ -66,7 +66,7 @@ boolean Plugin_005(uint8_t function, struct EventStruct *event, String& string)
         const __FlashStringHelper * options[] = { F("DHT 11"), F("DHT 22"), F("DHT 12"), F("Sonoff am2301"), F("Sonoff si7021"), F("Sonoff MS01") };
         const int indices[] = { P005_DHT11, P005_DHT22, P005_DHT12, P005_AM2301, P005_SI7021, P005_MS01 };
 
-        constexpr size_t nrElements = sizeof(indices) / sizeof(indices[0]);
+        constexpr size_t nrElements = NR_ELEMENTS(indices);
 
         addFormSelector(F("Sensor model"), F("dhttype"), nrElements, options, indices, PCONFIG(0) );
 
diff --git a/src/_P026_Sysinfo.ino b/src/_P026_Sysinfo.ino
index 188891355..9139efece 100644
--- a/src/_P026_Sysinfo.ino
+++ b/src/_P026_Sysinfo.ino
@@ -42,7 +42,7 @@ const __FlashStringHelper* Plugin_026_valuename(uint8_t value_nr, bool displaySt
     F("Free 2nd Heap"), F("free2ndheap")
   };
   const size_t index = (2* value_nr) + (displayString ? 0 : 1);
-  constexpr size_t nrStrings = sizeof(strings) / sizeof(strings[0]);
+  constexpr size_t nrStrings = NR_ELEMENTS(strings);
   if (index < nrStrings) {
     return strings[index];
   }
diff --git a/src/_P076_HLW8012.ino b/src/_P076_HLW8012.ino
index b19fafa98..1925b3283 100644
--- a/src/_P076_HLW8012.ino
+++ b/src/_P076_HLW8012.ino
@@ -173,7 +173,7 @@ boolean Plugin_076(uint8_t function, struct EventStruct *event, String& string)
           P076_Gosund,
           P076_Shelly_PLUG_S
         };
-        constexpr int nrElements = sizeof(predefinedId) / sizeof(predefinedId[0]);
+        constexpr int nrElements = NR_ELEMENTS(predefinedId);
         addFormSelector(F("Device"),
                         F("preDefDevSel"), nrElements,
                         predefinedNames, predefinedId, devicePinSettings);
diff --git a/src/_P078_Eastron.ino b/src/_P078_Eastron.ino
index e25b56233..9e6dc3689 100644
--- a/src/_P078_Eastron.ino
+++ b/src/_P078_Eastron.ino
@@ -178,7 +178,7 @@ boolean Plugin_078(uint8_t function, struct EventStruct *event, String& string)
           F("SDM72_V2"),
           F("SDM320C")
         };
-        constexpr size_t nrOptions = sizeof(options_model) / sizeof(options_model[0]);
+        constexpr size_t nrOptions = NR_ELEMENTS(options_model);
         addFormSelector(F("Model Type"), P078_MODEL_LABEL, nrOptions, options_model, nullptr, P078_MODEL);
         addFormNote(F("Submit after changing the modell to update Output Configuration."));
       }
@@ -378,7 +378,7 @@ boolean Plugin_078(uint8_t function, struct EventStruct *event, String& string)
 
               if (new_baud > 5) {
                 const int baudrates[]     = { 2400, 4800, 9600, 19200, 38400, 1200 };
-                constexpr int nrBaudRates = sizeof(baudrates) / sizeof(baudrates[0]);
+                constexpr int nrBaudRates = NR_ELEMENTS(baudrates);
 
                 for (int i = 0; i < nrBaudRates && new_baud > 5; ++i) {
                   if (new_baud == baudrates[i]) {
diff --git a/src/_P148_POWRxxD_THR3xxD.ino b/src/_P148_POWRxxD_THR3xxD.ino
index 0ab3a394d..bb90e7573 100644
--- a/src/_P148_POWRxxD_THR3xxD.ino
+++ b/src/_P148_POWRxxD_THR3xxD.ino
@@ -71,7 +71,7 @@ boolean Plugin_148(uint8_t function, struct EventStruct *event, String& string)
         P148_GPIO_TM1621_RD,
         P148_GPIO_TM1621_CS
       };
-      constexpr size_t nrElements = sizeof(values) / sizeof(values[0]);
+      constexpr size_t nrElements = NR_ELEMENTS(values);
 
       for (size_t i = 0; i < nrElements; ++i) {
         if (i != 0) { addHtml(event->String1); }
@@ -126,7 +126,7 @@ boolean Plugin_148(uint8_t function, struct EventStruct *event, String& string)
           static_cast<int>(P148_data_struct::Tm1621Device::POWR3xxD),
           static_cast<int>(P148_data_struct::Tm1621Device::THR3xxD)
         };
-        constexpr size_t nrElements = sizeof(optionValues) / sizeof(optionValues[0]);
+        constexpr size_t nrElements = NR_ELEMENTS(optionValues);
 
         addFormSelector(F("Device Template"), F("devtmpl"), nrElements, options, optionValues, P148_DEVICE_SELECTOR);
         addFormNote(F("GPIO settings will be ignored when selecting other than 'Custom'"));
diff --git a/src/include/ESPEasy_config.h b/src/include/ESPEasy_config.h
index f78935bd3..5c1bd4932 100644
--- a/src/include/ESPEasy_config.h
+++ b/src/include/ESPEasy_config.h
@@ -82,6 +82,7 @@
 
 #define ZERO_FILL(S)  memset((S), 0, sizeof(S))
 #define ZERO_TERMINATE(S)  S[sizeof(S) - 1] = 0
+#define NR_ELEMENTS(ARR) sizeof(ARR) / sizeof(ARR[0])
 
 #ifdef ESP32
   // Special macros to disable interrupts from within an ISR function.
diff --git a/src/src/DataStructs_templ/SettingsStruct.cpp b/src/src/DataStructs_templ/SettingsStruct.cpp
index 0c232fc58..78bc968d1 100644
--- a/src/src/DataStructs_templ/SettingsStruct.cpp
+++ b/src/src/DataStructs_templ/SettingsStruct.cpp
@@ -575,15 +575,15 @@ void SettingsStruct_tmpl<N_TASKS>::clearMisc() {
     // Here we initialize all data to 0, so this is the ONLY reason why PinBootStates 
     // can now be directly accessed.
     // In all other use cases, use the get and set functions for it.
-    constexpr uint8_t maxStates = sizeof(PinBootStates) / sizeof(PinBootStates[0]);
+    constexpr size_t maxStates = NR_ELEMENTS(PinBootStates);
 
-    for (uint8_t i = 0; i < maxStates; ++i) {
+    for (size_t i = 0; i < maxStates; ++i) {
       PinBootStates[i] = 0;
     }
     # ifdef ESP32
-    constexpr uint8_t maxStatesesp32 = sizeof(PinBootStates_ESP32) / sizeof(PinBootStates_ESP32[0]);
+    constexpr size_t maxStatesesp32 = NR_ELEMENTS(PinBootStates_ESP32);
 
-    for (uint8_t i = 0; i < maxStatesesp32; ++i) {
+    for (size_t i = 0; i < maxStatesesp32; ++i) {
       PinBootStates_ESP32[i] = 0;
     }
     # endif // ifdef ESP32
@@ -710,14 +710,14 @@ bool SettingsStruct_tmpl<N_TASKS>::getPinBootStateIndex(
 
   if (!GPIO_IS_VALID_GPIO(gpio_pin)) { return false; }
 # endif // ifdef ESP32
-  constexpr uint8_t maxStates = sizeof(PinBootStates) / sizeof(PinBootStates[0]);
+  constexpr uint8_t maxStates = NR_ELEMENTS(PinBootStates);
 
   if (gpio_pin < maxStates) {
     index_low = gpio_pin;
     return true;
   }
 # ifdef ESP32
-  constexpr uint8_t maxStatesesp32 = sizeof(PinBootStates_ESP32) / sizeof(PinBootStates_ESP32[0]);
+  constexpr uint8_t maxStatesesp32 = NR_ELEMENTS(PinBootStates_ESP32);
 
   index_high = gpio_pin - maxStates;
 
diff --git a/src/src/Helpers/Convert.cpp b/src/src/Helpers/Convert.cpp
index c68cb7806..e40851b60 100644
--- a/src/src/Helpers/Convert.cpp
+++ b/src/src/Helpers/Convert.cpp
@@ -25,7 +25,7 @@ const __FlashStringHelper * getBearing(int degrees)
     F("NW"),
     F("NNW")
   };
-  constexpr size_t nrDirections = sizeof(directions) / sizeof(directions[0]);
+  constexpr size_t nrDirections = NR_ELEMENTS(directions);
   const float stepsize          = (360.0f / nrDirections);
 
   if (degrees < 0) { degrees += 360; } // Allow for bearing -360 .. 359
@@ -38,14 +38,15 @@ const __FlashStringHelper * getBearing(int degrees)
 }
 
 float CelsiusToFahrenheit(float celsius) {
-  return celsius * (9.0f / 5.0f) + 32;
+  constexpr float ratio = 9.0f / 5.0f;
+  return celsius * ratio + 32;
 }
 
 int m_secToBeaufort(float m_per_sec) {
   // Use ints wit 0.1 m/sec resolution to reduce size.
   const uint16_t dm_per_sec = 10 * m_per_sec;
   const uint16_t speeds[]{3, 16, 34, 55, 80, 108, 139, 172, 208, 245, 285, 326};  
-  constexpr int nrElements = sizeof(speeds) / sizeof(speeds[0]);
+  constexpr int nrElements = NR_ELEMENTS(speeds);
   
   for (int bft = 0; bft < nrElements; ++bft) {
     if (dm_per_sec < speeds[bft]) return bft;
diff --git a/src/src/Helpers/ESPEasy_Storage.cpp b/src/src/Helpers/ESPEasy_Storage.cpp
index 5864d35d7..d486392c3 100644
--- a/src/src/Helpers/ESPEasy_Storage.cpp
+++ b/src/src/Helpers/ESPEasy_Storage.cpp
@@ -354,7 +354,7 @@ bool BuildFixes()
   }
   if (Settings.Build < 20111) {
     #ifdef ESP32
-    constexpr uint8_t maxStatesesp32 = sizeof(Settings.PinBootStates_ESP32) / sizeof(Settings.PinBootStates_ESP32[0]);
+    constexpr uint8_t maxStatesesp32 = NR_ELEMENTS(Settings.PinBootStates_ESP32);
     for (uint8_t i = 0; i < maxStatesesp32; ++i) {
       Settings.PinBootStates_ESP32[i] = 0;
     }
diff --git a/src/src/Helpers/Rules_calculate.cpp b/src/src/Helpers/Rules_calculate.cpp
index f5fe0034f..1a93ecb76 100644
--- a/src/src/Helpers/Rules_calculate.cpp
+++ b/src/src/Helpers/Rules_calculate.cpp
@@ -647,7 +647,7 @@ String RulesCalculate_t::preProces(const String& input)
 
   };
 
-  constexpr size_t nrOperators = sizeof(operators) / sizeof(operators[0]);
+  constexpr size_t nrOperators = NR_ELEMENTS(operators);
 
   for (size_t i = 0; i < nrOperators; ++i) {
     const UnaryOperator op = operators[i];
diff --git a/src/src/Helpers/_CPlugin_init.cpp b/src/src/Helpers/_CPlugin_init.cpp
index a2741f7c4..a2e14abc5 100644
--- a/src/src/Helpers/_CPlugin_init.cpp
+++ b/src/src/Helpers/_CPlugin_init.cpp
@@ -2073,7 +2073,7 @@ protocolIndex_t CPlugin_id_to_ProtocolIndex[CPLUGIN_MAX + 1]{};
 constexpr size_t ProtocolIndex_to_CPlugin_id_size = sizeof(ProtocolIndex_to_CPlugin_id);
 
 // constexpr size_t Plugin_ptr_size               = sizeof(Plugin_ptr);
-constexpr size_t CPlugin_id_to_ProtocolIndex_size = sizeof(CPlugin_id_to_ProtocolIndex) / sizeof(CPlugin_id_to_ProtocolIndex[0]);
+constexpr size_t CPlugin_id_to_ProtocolIndex_size = NR_ELEMENTS(CPlugin_id_to_ProtocolIndex);
 
 
 protocolIndex_t getProtocolIndex_from_CPluginID_(cpluginID_t cpluginID)
diff --git a/src/src/Helpers/_Plugin_Helper_serial.cpp b/src/src/Helpers/_Plugin_Helper_serial.cpp
index 72d396f30..1a2628bd3 100644
--- a/src/src/Helpers/_Plugin_Helper_serial.cpp
+++ b/src/src/Helpers/_Plugin_Helper_serial.cpp
@@ -272,7 +272,7 @@ void serialHelper_webformLoad(ESPEasySerialPort port, int rxPinDef, int txPinDef
 #endif // if USES_I2C_SC16IS752
   };
 
-  constexpr int NR_ESPEASY_SERIAL_TYPES = sizeof(ids) / sizeof(ids[1]);
+  constexpr int NR_ESPEASY_SERIAL_TYPES = NR_ELEMENTS(ids);
   String options[NR_ESPEASY_SERIAL_TYPES];
 
 //  String attr[NR_ESPEASY_SERIAL_TYPES];
diff --git a/src/src/Helpers/_Plugin_SensorTypeHelper.cpp b/src/src/Helpers/_Plugin_SensorTypeHelper.cpp
index 686299d40..c42b7edda 100644
--- a/src/src/Helpers/_Plugin_SensorTypeHelper.cpp
+++ b/src/src/Helpers/_Plugin_SensorTypeHelper.cpp
@@ -43,7 +43,7 @@ void sensorTypeHelper_webformLoad_allTypes(struct EventStruct *event, uint8_t pc
 #endif
     static_cast<uint8_t>(Sensor_VType::SENSOR_TYPE_STRING)
   };
-  constexpr int optionCount = sizeof(optionValues) / sizeof(optionValues[0]);
+  constexpr int optionCount = NR_ELEMENTS(optionValues);
 
   sensorTypeHelper_webformLoad(event, pconfigIndex, optionCount, optionValues);
 }
@@ -56,7 +56,7 @@ void sensorTypeHelper_webformLoad_simple(struct EventStruct *event, uint8_t pcon
     static_cast<uint8_t>(Sensor_VType::SENSOR_TYPE_TRIPLE),
     static_cast<uint8_t>(Sensor_VType::SENSOR_TYPE_QUAD)
   };
-  constexpr int optionCount = sizeof(optionValues) / sizeof(optionValues[0]);
+  constexpr int optionCount = NR_ELEMENTS(optionValues);
 
   sensorTypeHelper_webformLoad(event, pconfigIndex, optionCount, optionValues);
 }
diff --git a/src/src/PluginStructs/P052_data_struct.cpp b/src/src/PluginStructs/P052_data_struct.cpp
index 363cab2e3..a362c2eaa 100644
--- a/src/src/PluginStructs/P052_data_struct.cpp
+++ b/src/src/PluginStructs/P052_data_struct.cpp
@@ -30,7 +30,7 @@ const __FlashStringHelper * P052_data_struct::Plugin_052_valuename(uint8_t value
     F("Error Status"),           F("err")
   };
   const size_t index = (2* value_nr) + (displayString ? 0 : 1);
-  constexpr size_t nrStrings = sizeof(strings) / sizeof(strings[0]);
+  constexpr size_t nrStrings = NR_ELEMENTS(strings);
   if (index < nrStrings) {
     return strings[index];
   }
diff --git a/src/src/PluginStructs/P077_data_struct.cpp b/src/src/PluginStructs/P077_data_struct.cpp
index 4e5f93846..2a201f00a 100644
--- a/src/src/PluginStructs/P077_data_struct.cpp
+++ b/src/src/PluginStructs/P077_data_struct.cpp
@@ -17,7 +17,7 @@ const __FlashStringHelper* Plugin_077_valuename(P077_query value_nr, bool displa
     F("Power Factor"),   F("pf"),
     F("Reactive Power"), F("VAR")
   };
-  constexpr size_t nrStrings = sizeof(strings) / sizeof(strings[0]);
+  constexpr size_t nrStrings = NR_ELEMENTS(strings);
   const size_t     index     = static_cast<size_t>(value_nr) * 2 + (displayString ? 0 : 1);
 
   if (index < nrStrings) {
@@ -71,7 +71,7 @@ bool P077_data_struct::init(ESPEasySerialPort port, const int16_t serial_rx, con
 
 uint32_t P077_data_struct::get_24bit_value(uint8_t offset) const {
   uint32_t res{};
-  constexpr size_t bufsize = sizeof(serial_in_buffer) / sizeof(serial_in_buffer[0]);
+  constexpr size_t bufsize = NR_ELEMENTS(serial_in_buffer);
 
   if ((offset + 2u) < bufsize) {
     res = serial_in_buffer[offset] << 16 |
@@ -311,7 +311,7 @@ bool P077_data_struct::checksumMatch() const
 }
 
 bool P077_data_struct::plugin_read(struct EventStruct *event) {
-  constexpr uint8_t nrElements = sizeof(_cache) / sizeof(_cache[0]);
+  constexpr uint8_t nrElements = NR_ELEMENTS(_cache);
 
   for (uint8_t i = 0; i < P077_NR_OUTPUT_VALUES; ++i) {
     const uint8_t pconfigIndex = i + P077_QUERY1_CONFIG_POS;
@@ -414,7 +414,7 @@ int P077_data_struct::serial_Available() {
 
 void P077_data_struct::setOutputValue(struct EventStruct *event, P077_query outputType, float value) {
   const uint8_t index          = static_cast<uint8_t>(outputType);
-  constexpr uint8_t nrElements = sizeof(_cache) / sizeof(_cache[0]);
+  constexpr uint8_t nrElements = NR_ELEMENTS(_cache);
 
   if (index < nrElements) {
     _cache[index].add(value);
@@ -443,7 +443,7 @@ void P077_data_struct::setOutputValue(struct EventStruct *event, P077_query outp
 float P077_data_struct::getValue(P077_query outputType) const
 {
   const uint8_t index          = static_cast<uint8_t>(outputType);
-  constexpr uint8_t nrElements = sizeof(_cache) / sizeof(_cache[0]);
+  constexpr uint8_t nrElements = NR_ELEMENTS(_cache);
 
   float res{};
 
diff --git a/src/src/PluginStructs/P078_data_struct.cpp b/src/src/PluginStructs/P078_data_struct.cpp
index 48e8dfc08..f4a50c5eb 100644
--- a/src/src/PluginStructs/P078_data_struct.cpp
+++ b/src/src/PluginStructs/P078_data_struct.cpp
@@ -130,7 +130,7 @@ constexpr p078_register_description register_description_list[] = {
 };
 // *INDENT-ON*
 
-constexpr int register_description_list_size = sizeof(register_description_list) / sizeof(register_description_list[0]);
+constexpr int register_description_list_size = NR_ELEMENTS(register_description_list);
 
 const __FlashStringHelper* SDM_UOMtoString(SDM_UOM uom, bool display) {
   const __FlashStringHelper *strings[] = {
@@ -148,7 +148,7 @@ const __FlashStringHelper* SDM_UOMtoString(SDM_UOM uom, bool display) {
     F("Apparent Energy"), F("kVAh"),
     F("Reactive Energy"), F("kVArh")
   };
-  constexpr size_t nrStrings = sizeof(strings) / sizeof(strings[0]);
+  constexpr size_t nrStrings = NR_ELEMENTS(strings);
   size_t index               = 2 * static_cast<size_t>(uom);
 
   if (!display) { ++index; }
diff --git a/src/src/WebServer/AdvancedConfigPage.cpp b/src/src/WebServer/AdvancedConfigPage.cpp
index 135f74de9..71ae6ed6c 100644
--- a/src/src/WebServer/AdvancedConfigPage.cpp
+++ b/src/src/WebServer/AdvancedConfigPage.cpp
@@ -321,9 +321,10 @@ void handle_advanced() {
     F("Dark"),
   };
   const int cssModeOptions[] = { 0, 1, 2};
+  constexpr int nrCssModeOptions = NR_ELEMENTS(cssModeOptions);
     addFormSelector(getLabel(LabelType::ENABLE_AUTO_DARK_MODE),
                     getInternalLabel(LabelType::ENABLE_AUTO_DARK_MODE),
-                    sizeof(cssModeOptions) / sizeof(int),
+                    nrCssModeOptions,
                     cssModeNames,
                     cssModeOptions,
                     Settings.getCssMode());
diff --git a/src/src/WebServer/ESPEasy_WebServer.cpp b/src/src/WebServer/ESPEasy_WebServer.cpp
index bb1dd1106..58b98bbf6 100644
--- a/src/src/WebServer/ESPEasy_WebServer.cpp
+++ b/src/src/WebServer/ESPEasy_WebServer.cpp
@@ -320,7 +320,7 @@ void WebServerInit()
   // List of headers to be recorded
   // "If-None-Match" is used to see whether we need to serve a static file, or simply can reply with a 304 (not modified)
   const char * headerkeys[] = {"If-None-Match"};
-  const size_t headerkeyssize = sizeof(headerkeys)/sizeof(char*);
+  constexpr size_t headerkeyssize = NR_ELEMENTS(headerkeys);
   web_server.collectHeaders(headerkeys, headerkeyssize );
   #if defined(ESP8266) || defined(ESP32)
   {
diff --git a/src/src/WebServer/HardwarePage.cpp b/src/src/WebServer/HardwarePage.cpp
index da92c03c9..9f970b4f0 100644
--- a/src/src/WebServer/HardwarePage.cpp
+++ b/src/src/WebServer/HardwarePage.cpp
@@ -210,7 +210,7 @@ void handle_hardware() {
       #endif
       static_cast<int>(SPI_Options_e::UserDefined)
     };
-    constexpr size_t nrOptions = sizeof(spi_index) / sizeof(spi_index[0]);
+    constexpr size_t nrOptions = NR_ELEMENTS(spi_index);
     addFormSelector_script(F("Init SPI"), F("initspi"), nrOptions, spi_options, spi_index, nullptr, Settings.InitSPI, F("spiOptionChanged(this)"));
     // User-defined pins
     addFormPinSelect(PinSelectPurpose::SPI, formatGpioName_output(F("CLK")),  F("spipinsclk"), Settings.SPI_SCLK_pin);