diff --git a/src/arm/midr.c b/src/arm/midr.c
index 62a0300..c5531df 100644
--- a/src/arm/midr.c
+++ b/src/arm/midr.c
@@ -40,12 +40,14 @@ struct cache* get_cache_info(struct cpuInfo* cpu) {
 struct frequency* get_frequency_info(uint32_t core) {
   struct frequency* freq = emalloc(sizeof(struct frequency));
 
+  freq->measured = false;
   freq->base = UNKNOWN_DATA;
   freq->max = get_max_freq_from_file(core);
   #ifdef __linux__
     if (freq->max == UNKNOWN_DATA) {
       printWarn("Unable to find max frequency from udev, measuring CPU frequency");
       freq->max = measure_max_frequency(core);
+      freq->measured = true;
     }
   #endif
 
diff --git a/src/common/cpu.c b/src/common/cpu.c
index a7d53ca..946c990 100644
--- a/src/common/cpu.c
+++ b/src/common/cpu.c
@@ -145,17 +145,25 @@ char* get_str_l3(struct cache* cach) {
 
 char* get_str_freq(struct frequency* freq) {
   //Max 3 digits and 3 for '(M/G)Hz' plus 1 for '\0'
-  uint32_t size = (5+1+3+1);
+  uint32_t size = (1+5+1+3+1);
   assert(strlen(STRING_UNKNOWN)+1 <= size);
-  char* string = emalloc(sizeof(char)*size);
-  memset(string, 0, sizeof(char)*size);
+  char* string = ecalloc(size, sizeof(char));
 
-  if(freq->max == UNKNOWN_DATA || freq->max < 0)
+  if(freq->max == UNKNOWN_DATA || freq->max < 0) {
     snprintf(string,strlen(STRING_UNKNOWN)+1,STRING_UNKNOWN);
-  else if(freq->max >= 1000)
-    snprintf(string,size,"%.3f "STRING_GIGAHERZ,(float)(freq->max)/1000);
-  else
-    snprintf(string,size,"%d "STRING_MEGAHERZ,freq->max);
+  }
+  else if(freq->max >= 1000) {
+    if (freq->measured)
+      snprintf(string,size,"~%.3f "STRING_GIGAHERZ,(float)(freq->max)/1000);
+    else
+      snprintf(string,size,"%.3f "STRING_GIGAHERZ,(float)(freq->max)/1000);
+  }
+  else {
+    if (freq->measured)
+      snprintf(string,size,"~%d "STRING_MEGAHERZ,freq->max);
+    else
+      snprintf(string,size,"%d "STRING_MEGAHERZ,freq->max);
+  }
 
   return string;
 }
diff --git a/src/common/cpu.h b/src/common/cpu.h
index da023e0..fbe0848 100644
--- a/src/common/cpu.h
+++ b/src/common/cpu.h
@@ -57,6 +57,8 @@ typedef int32_t VENDOR;
 struct frequency {
   int32_t base;
   int32_t max;
+  // Indicates if max frequency was measured
+  bool measured;
 };
 
 struct hypervisor {
diff --git a/src/ppc/ppc.c b/src/ppc/ppc.c
index 90ae308..4758d27 100644
--- a/src/ppc/ppc.c
+++ b/src/ppc/ppc.c
@@ -146,6 +146,7 @@ struct uarch* get_cpu_uarch(struct cpuInfo* cpu) {
 struct frequency* get_frequency_info(void) {
   struct frequency* freq = emalloc(sizeof(struct frequency));
 
+  freq->measured = false;
   freq->max = get_max_freq_from_file(0);
   freq->base = get_min_freq_from_file(0);
 
diff --git a/src/riscv/riscv.c b/src/riscv/riscv.c
index c9e1b1f..b378f30 100644
--- a/src/riscv/riscv.c
+++ b/src/riscv/riscv.c
@@ -19,6 +19,7 @@
 struct frequency* get_frequency_info(uint32_t core) {
   struct frequency* freq = emalloc(sizeof(struct frequency));
 
+  freq->measured = false;
   freq->base = UNKNOWN_DATA;
   freq->max = get_max_freq_from_file(core);
 
diff --git a/src/x86/cpuid.c b/src/x86/cpuid.c
index 48f10f8..84821d6 100644
--- a/src/x86/cpuid.c
+++ b/src/x86/cpuid.c
@@ -923,6 +923,7 @@ struct cache* get_cache_info(struct cpuInfo* cpu) {
 
 struct frequency* get_frequency_info(struct cpuInfo* cpu) {
   struct frequency* freq = emalloc(sizeof(struct frequency));
+  freq->measured = false;
 
   if(cpu->maxLevels < 0x00000016) {
     #if defined (_WIN32) || defined (__APPLE__)
@@ -976,6 +977,7 @@ struct frequency* get_frequency_info(struct cpuInfo* cpu) {
       printWarn("All previous methods failed, measuring CPU frequency");
       // TODO: Support hybrid architectures
       freq->max = measure_max_frequency(0);
+      freq->measured = true;
     }
   #endif