diff --git a/doc/api/net.md b/doc/api/net.md
index f8cd3ccf8d3c40..e1de1958f4cf42 100644
--- a/doc/api/net.md
+++ b/doc/api/net.md
@@ -1402,6 +1402,10 @@ data packet received and the first keepalive probe. Setting `0` for
 `initialDelay` will leave the value unchanged from the default
 (or previous) setting.
 
+**Note**: Node.js converts initialDelay from milliseconds to seconds and truncates any fractional part.
+For example, `setKeepAlive(true, 500)` does not update the delay because it is truncated to `0`, leaving the value
+unchanged, while `setKeepAlive(true, 1500)` sets it to `1` second.
+
 Enabling the keep-alive functionality will set the following socket options:
 
 * `SO_KEEPALIVE=1`