diff --git a/eww/eww-battery-monitor b/eww/eww-battery-monitor
index d5ae9c7..cc0fe37 100755
--- a/eww/eww-battery-monitor
+++ b/eww/eww-battery-monitor
@@ -56,13 +56,24 @@ function warn_if_low() {
 
 function print_state() {
     percentage = state_info["percentage"]
-    printf "%s%s%d%%\n",
-           get_icon(percentage),
-           state_info["charging"] ? "󱐋" : "",
-           percentage
+    tooltip = ""
+    if (state_info["charging"]) {
+        tooltip = "Until Full: " state_info["time to full"]
+    } else {
+        tooltip = "Until Empty: " state_info["time to empty"]
+    }
+    printf "{\"text\":\"%s%s%d%%\",\"tooltip\":\"%s\"}\n",
+        get_icon(percentage),
+        state_info["charging"] ? "󱐋" : "",
+        percentage,
+        tooltip
     fflush()
 }
 
+function string_or(str, def) {
+    return str == "" ? def : str
+}
+
 function parse_record(record, exit_on_absent) {
     split(record, fields)
     for (i in fields) {
@@ -77,6 +88,8 @@ function parse_record(record, exit_on_absent) {
     } else if ((! BATTERY && props["power supply"] == "yes" && \
          props["native-path"] ~ /BAT[0-9]+/) || name == BATTERY) {
         state_info["percentage"] = props["percentage"] + 0
+        state_info["time to full"] = string_or(props["time to full"], "Unknown")
+        state_info["time to empty"] = string_or(props["time to empty"], "Unknown")
         return 1
     } else if ((! ADAPTER && props["power supply"] == "yes" && \
                 props["native-path"] ~ /ADP[0-9]+/) || name == ADAPTER) {