diff --git a/adc.c b/adc.c
index f3e3491..86bf37b 100644
--- a/adc.c
+++ b/adc.c
@@ -20,7 +20,7 @@ void adc_setup(void) {
 
 uint32_t adc_bat_voltage(void) {
   if (adc_get_flag(ADC1, ADC_SR_EOC)) {
-    bat_voltage_mv = adc_read_regular(ADC1);
+    bat_voltage_mv = adc_read_regular(ADC1) * 3300 / 2048;
   }
   return bat_voltage_mv;
 }