diff --git a/firmware/application/tone_key.cpp b/firmware/application/tone_key.cpp
index 5f6aaf98..44858786 100644
--- a/firmware/application/tone_key.cpp
+++ b/firmware/application/tone_key.cpp
@@ -85,7 +85,7 @@ const tone_key_t tone_keys = {
     {"Senn. 32.768k", F2Ix100(32768.0)}};
 
 std::string fx100_string(uint32_t f) {
-    return to_string_dec_uint(f / 100) + "." + to_string_dec_uint((f / 10) % 10);
+    return to_string_dec_uint(f / 100) + "." + to_string_dec_uint(((f + 5) / 10) % 10);
 }
 
 float tone_key_frequency(tone_index index) {
diff --git a/firmware/application/tone_key.hpp b/firmware/application/tone_key.hpp
index f2e998f0..6866bfc4 100644
--- a/firmware/application/tone_key.hpp
+++ b/firmware/application/tone_key.hpp
@@ -31,7 +31,7 @@ namespace tonekey {
 
 #define TONE_FREQ_TOLERANCE_CENTIHZ (4 * 100)
 #define TONE_DISPLAY_TOGGLE_COUNTER 3
-#define F2Ix100(x) (int32_t)(x * 100.0)
+#define F2Ix100(x) (int32_t)(x * 100.0 + 0.5)  // add 0.5f to round vs truncate during FP->int conversion
 
 using tone_index = int32_t;
 using tone_key_t = std::vector<std::pair<std::string, uint32_t>>;