diff --git a/boards/airfy-beacon/include/periph_conf.h b/boards/airfy-beacon/include/periph_conf.h
index 4831b6b824..620d15760c 100644
--- a/boards/airfy-beacon/include/periph_conf.h
+++ b/boards/airfy-beacon/include/periph_conf.h
@@ -33,7 +33,6 @@
  *
  * @{
  */
-#define CLOCK_CORECLOCK     (16000000U)     /* fixed for all nRF51822 */
 #define CLOCK_HFCLK         (16U)           /* set to  0: internal RC oscillator
                                                       16: 16MHz crystal
                                                       32: 32MHz crystal */
diff --git a/boards/calliope-mini/include/periph_conf.h b/boards/calliope-mini/include/periph_conf.h
index 4680d07cb3..9578073058 100644
--- a/boards/calliope-mini/include/periph_conf.h
+++ b/boards/calliope-mini/include/periph_conf.h
@@ -32,7 +32,6 @@ extern "C" {
  *
  * @{
  */
-#define CLOCK_CORECLOCK     (16000000U)     /* fixed for all nRF51822 */
 #define CLOCK_HFCLK         (16U)           /* set to  0: internal RC oscillator
                                                       16: 16MHz crystal
                                                       32: 32MHz crystal */
diff --git a/boards/microbit/include/periph_conf.h b/boards/microbit/include/periph_conf.h
index 804a0cf226..ed0ccd0425 100644
--- a/boards/microbit/include/periph_conf.h
+++ b/boards/microbit/include/periph_conf.h
@@ -32,7 +32,6 @@ extern "C" {
  *
  * @{
  */
-#define CLOCK_CORECLOCK     (16000000U)     /* fixed for all nRF51822 */
 #define CLOCK_HFCLK         (16U)           /* set to  0: internal RC oscillator
                                                       16: 16MHz crystal
                                                       32: 32MHz crystal */
diff --git a/boards/nrf51dongle/include/periph_conf.h b/boards/nrf51dongle/include/periph_conf.h
index 315c61fecc..cfa34d41bc 100644
--- a/boards/nrf51dongle/include/periph_conf.h
+++ b/boards/nrf51dongle/include/periph_conf.h
@@ -32,7 +32,6 @@ extern "C" {
  *
  * @{
  */
-#define CLOCK_CORECLOCK     (16000000U)     /* fixed for all nRF51822 */
 #define CLOCK_HFCLK         (16U)           /* set to  0: internal RC oscillator
                                                       16: 16MHz crystal
                                                       32: 32MHz crystal */
diff --git a/boards/nrf6310/include/periph_conf.h b/boards/nrf6310/include/periph_conf.h
index f2cfa01ff4..67d63b06a7 100644
--- a/boards/nrf6310/include/periph_conf.h
+++ b/boards/nrf6310/include/periph_conf.h
@@ -35,7 +35,6 @@ extern "C" {
  *
  * @{
  */
-#define CLOCK_CORECLOCK     (16000000U)     /* fixed for all nRF51822 */
 #define CLOCK_HFCLK         (16U)           /* set to  0: internal RC oscillator
                                                       16: 16MHz crystal
                                                       32: 32MHz crystal */
diff --git a/boards/pca10000/include/periph_conf.h b/boards/pca10000/include/periph_conf.h
index d95e9a7930..64c4a7e2e1 100644
--- a/boards/pca10000/include/periph_conf.h
+++ b/boards/pca10000/include/periph_conf.h
@@ -34,7 +34,6 @@ extern "C" {
  *
  * @{
  */
-#define CLOCK_CORECLOCK     (16000000U)     /* fixed for all nRF51822 */
 #define CLOCK_HFCLK         (16U)           /* set to  0: internal RC oscillator
                                                       16: 16MHz crystal
                                                       32: 32MHz crystal */
diff --git a/boards/pca10005/include/periph_conf.h b/boards/pca10005/include/periph_conf.h
index 26c290f075..3e1435f9a2 100644
--- a/boards/pca10005/include/periph_conf.h
+++ b/boards/pca10005/include/periph_conf.h
@@ -34,7 +34,6 @@ extern "C" {
  *
  * @{
  */
-#define CLOCK_CORECLOCK     (16000000U)     /* fixed for all nRF51822 */
 #define CLOCK_HFCLK         (16U)           /* set to  0: internal RC oscillator
                                                       16: 16MHz crystal
                                                       32: 32MHz crystal */
diff --git a/boards/yunjia-nrf51822/include/periph_conf.h b/boards/yunjia-nrf51822/include/periph_conf.h
index f37321198b..50992a1065 100644
--- a/boards/yunjia-nrf51822/include/periph_conf.h
+++ b/boards/yunjia-nrf51822/include/periph_conf.h
@@ -32,7 +32,6 @@ extern "C" {
  *
  * @{
  */
-#define CLOCK_CORECLOCK     (16000000U)     /* fixed for all nRF51822 */
 #define CLOCK_HFCLK         (16U)           /* set to  0: internal RC oscillator
                                                       16: 16MHz crystal
                                                       32: 32MHz crystal */
diff --git a/cpu/nrf51/include/periph_cpu.h b/cpu/nrf51/include/periph_cpu.h
index d41b968a5e..251bd319c7 100644
--- a/cpu/nrf51/include/periph_cpu.h
+++ b/cpu/nrf51/include/periph_cpu.h
@@ -25,6 +25,11 @@
 extern "C" {
 #endif
 
+/**
+ * @brief   System core clock speed, fixed to 16MHz for all NRF51x CPUs
+ */
+#define CLOCK_CORECLOCK     (16000000U)
+
 /**
  * @brief   Redefine some peripheral names to unify them between nRF51 and 52
  * @{