diff --git a/neqo-bin/src/lib.rs b/neqo-bin/src/lib.rs
index d53a5039eb..c7d7ca883e 100644
--- a/neqo-bin/src/lib.rs
+++ b/neqo-bin/src/lib.rs
@@ -17,7 +17,7 @@ use std::{
 use clap::Parser;
 use neqo_transport::{
     tparams::PreferredAddress, CongestionControlAlgorithm, ConnectionParameters, StreamType,
-    Version,
+    Version, INITIAL_RTT,
 };
 
 pub mod client;
@@ -117,9 +117,9 @@ pub struct QuicParameters {
     /// The idle timeout for connections, in seconds.
     pub idle_timeout: u64,
 
-    #[arg(long = "init_rtt", default_value = "100")]
-    /// The initial round-trip time.
-    pub initial_rtt_ms: u64,
+    #[arg(long = "init_rtt")]
+    /// The initial round-trip time. Defaults to [``INITIAL_RTT``] if not specified.
+    pub initial_rtt_ms: Option<u64>,
 
     #[arg(long = "cc", default_value = "newreno")]
     /// The congestion controller to use.
@@ -150,6 +150,7 @@ impl Default for QuicParameters {
             max_streams_bidi: 16,
             max_streams_uni: 16,
             idle_timeout: 30,
+            initial_rtt_ms: None,
             congestion_control: CongestionControlAlgorithm::NewReno,
             no_pacing: false,
             no_pmtud: false,
@@ -226,7 +227,10 @@ impl QuicParameters {
             .max_streams(StreamType::BiDi, self.max_streams_bidi)
             .max_streams(StreamType::UniDi, self.max_streams_uni)
             .idle_timeout(Duration::from_secs(self.idle_timeout))
-            .initial_rtt(Duration::from_millis(self.initial_rtt_ms))
+            .initial_rtt(
+                self.initial_rtt_ms
+                    .map_or(INITIAL_RTT, Duration::from_millis),
+            )
             .cc_algorithm(self.congestion_control)
             .pacing(!self.no_pacing)
             .pmtud(!self.no_pmtud);
diff --git a/neqo-transport/src/connection/params.rs b/neqo-transport/src/connection/params.rs
index d73da35e0d..c4bc38d2c3 100644
--- a/neqo-transport/src/connection/params.rs
+++ b/neqo-transport/src/connection/params.rs
@@ -10,7 +10,7 @@ pub use crate::recovery::FAST_PTO_SCALE;
 use crate::{
     connection::{ConnectionIdManager, Role, LOCAL_ACTIVE_CID_LIMIT},
     recv_stream::RECV_BUFFER_SIZE,
-    rtt::{DEFAULT_INITIAL_RTT, GRANULARITY},
+    rtt::{GRANULARITY, INITIAL_RTT},
     stream_id::StreamType,
     tparams::{self, PreferredAddress, TransportParameter, TransportParametersHandler},
     tracking::DEFAULT_ACK_DELAY,
@@ -99,7 +99,7 @@ impl Default for ConnectionParameters {
             max_streams_uni: LOCAL_STREAM_LIMIT_UNI,
             ack_ratio: DEFAULT_ACK_RATIO,
             idle_timeout: DEFAULT_IDLE_TIMEOUT,
-            initial_rtt: DEFAULT_INITIAL_RTT,
+            initial_rtt: INITIAL_RTT,
             preferred_address: PreferredAddressConfig::Default,
             datagram_size: 0,
             outgoing_datagram_queue: MAX_QUEUED_DATAGRAMS_DEFAULT,
diff --git a/neqo-transport/src/connection/tests/mod.rs b/neqo-transport/src/connection/tests/mod.rs
index 25349bad74..3528f7d488 100644
--- a/neqo-transport/src/connection/tests/mod.rs
+++ b/neqo-transport/src/connection/tests/mod.rs
@@ -697,8 +697,8 @@ fn create_client() {
     assert!(matches!(client.state(), State::Init));
     let stats = client.stats();
     assert_default_stats(&stats);
-    assert_eq!(stats.rtt, crate::rtt::DEFAULT_INITIAL_RTT);
-    assert_eq!(stats.rttvar, crate::rtt::DEFAULT_INITIAL_RTT / 2);
+    assert_eq!(stats.rtt, crate::rtt::INITIAL_RTT);
+    assert_eq!(stats.rttvar, crate::rtt::INITIAL_RTT / 2);
 }
 
 #[test]
diff --git a/neqo-transport/src/lib.rs b/neqo-transport/src/lib.rs
index 7b650b7f2e..4e93c143d6 100644
--- a/neqo-transport/src/lib.rs
+++ b/neqo-transport/src/lib.rs
@@ -50,6 +50,8 @@ pub mod tparams;
 mod tracking;
 pub mod version;
 
+pub use rtt::INITIAL_RTT;
+
 pub use self::{
     cc::CongestionControlAlgorithm,
     cid::{
diff --git a/neqo-transport/src/rtt.rs b/neqo-transport/src/rtt.rs
index 37128ac92e..ba623a1a1c 100644
--- a/neqo-transport/src/rtt.rs
+++ b/neqo-transport/src/rtt.rs
@@ -25,7 +25,7 @@ use crate::{
 /// `select()`, or similar) can reliably deliver; see `neqo_common::hrtime`.
 pub const GRANULARITY: Duration = Duration::from_millis(1);
 // Defined in -recovery 6.2 as 333ms but using lower value.
-pub const DEFAULT_INITIAL_RTT: Duration = Duration::from_millis(100);
+pub const INITIAL_RTT: Duration = Duration::from_millis(100);
 
 /// The source of the RTT measurement.
 #[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, Copy)]
@@ -219,10 +219,10 @@ impl Default for RttEstimate {
     fn default() -> Self {
         Self {
             first_sample_time: None,
-            latest_rtt: DEFAULT_INITIAL_RTT,
-            smoothed_rtt: DEFAULT_INITIAL_RTT,
-            rttvar: DEFAULT_INITIAL_RTT / 2,
-            min_rtt: DEFAULT_INITIAL_RTT,
+            latest_rtt: INITIAL_RTT,
+            smoothed_rtt: INITIAL_RTT,
+            rttvar: INITIAL_RTT / 2,
+            min_rtt: INITIAL_RTT,
             ack_delay: PeerAckDelay::default(),
             best_source: RttSource::Guesstimate,
         }