diff --git a/cores/esp8266/Arduino.h b/cores/esp8266/Arduino.h
index 19c25e899..6b9aedcfb 100644
--- a/cores/esp8266/Arduino.h
+++ b/cores/esp8266/Arduino.h
@@ -186,4 +186,48 @@ long map(long, long, long, long, long);
 
 #include "pins_arduino.h"
 
+/**
+ * User-defined Literals
+ *  usage:
+ *
+ *   uint32_t = test = 10_MHz; // --> 10000000
+ */
+#ifdef __cplusplus
+unsigned long long operator"" _kHz(unsigned long long x) {
+    return x * 1000;
+}
+
+unsigned long long operator"" _MHz(unsigned long long x) {
+    return x * 1000 * 1000;
+}
+
+unsigned long long operator"" _GHz(unsigned long long x) {
+    return x * 1000 * 1000 * 1000;
+}
+
+unsigned long long operator"" _kBit(unsigned long long x) {
+    return x * 1024;
+}
+
+unsigned long long operator"" _MBit(unsigned long long x) {
+    return x * 1024 * 1024;
+}
+
+unsigned long long operator"" _GBit(unsigned long long x) {
+    return x * 1024 * 1024 * 1024;
+}
+
+unsigned long long operator"" _kB(unsigned long long x) {
+    return x * 1024;
+}
+
+unsigned long long operator"" _MB(unsigned long long x) {
+    return x * 1024 * 1024;
+}
+
+unsigned long long operator"" _GB(unsigned long long x) {
+    return x * 1024 * 1024 * 1024;
+}
+#endif
+
 #endif
diff --git a/cores/esp8266/Esp.cpp b/cores/esp8266/Esp.cpp
index 190ff3009..5dafde53e 100644
--- a/cores/esp8266/Esp.cpp
+++ b/cores/esp8266/Esp.cpp
@@ -24,18 +24,6 @@ extern "C" {
 #include "user_interface.h"
 }
 
-#define kHz (1000L)
-#define MHz (1000L*kHz)
-#define GHz (1000L*MHz)
-
-#define kBit (1024L)
-#define MBit (1024L*kBit)
-#define GBit (1024L*MBit)
-
-#define kB (1024L)
-#define MB (1024L*kB)
-#define GB (1024L*MB)
-
 //extern "C" void ets_wdt_init(uint32_t val);
 extern "C" void ets_wdt_enable(void);
 extern "C" void ets_wdt_disable(void);
@@ -134,15 +122,15 @@ uint32_t EspClass::getFlashChipSize(void)
     if(spi_flash_read(0x0000, &data, 4) == SPI_FLASH_RESULT_OK) {
         switch((bytes[3] & 0xf0) >> 4) {
             case 0x0: // 4 Mbit (512KB)
-                return (512 * kB);
+                return (512_kB);
             case 0x1: // 2 MBit (256KB)
-                return (256 * kB);
+                return (256_kB);
             case 0x2: // 8 MBit (1MB)
-                return (1 * MB);
+                return (1_MB);
             case 0x3: // 16 MBit (2MB)
-                return (2 * MB);
+                return (2_MB);
             case 0x4: // 32 MBit (4MB)
-                return (4 * MB);
+                return (4_MB);
             default: // fail?
                 return 0;
         }
@@ -158,13 +146,13 @@ uint32_t EspClass::getFlashChipSpeed(void)
     if(spi_flash_read(0x0000, &data, 4) == SPI_FLASH_RESULT_OK) {
         switch(bytes[3] & 0x0F) {
             case 0x0: // 40 MHz
-                return (40 * MHz);
+                return (40_MHz);
             case 0x1: // 26 MHz
-                return (26 * MHz);
+                return (26_MHz);
             case 0x2: // 20 MHz
-                return (20 * MHz);
+                return (20_MHz);
             case 0xf: // 80 MHz
-                return (80 * MHz);
+                return (80_MHz);
             default: // fail?
                 return 0;
         }