diff --git a/Cargo.lock b/Cargo.lock
index 7e7c5ff87dc0..939863e05c8f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -8333,6 +8333,7 @@ dependencies = [
  "derive_more",
  "eyre",
  "futures",
+ "maili-flz",
  "op-alloy-consensus",
  "op-alloy-rpc-types-engine",
  "parking_lot",
diff --git a/Cargo.toml b/Cargo.toml
index 42a94ea63f63..d2186ac016cf 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -472,9 +472,11 @@ alloy-transport-ws = { version = "0.9.2", default-features = false }
 # op
 op-alloy-rpc-types = { version = "0.9.0", default-features = false }
 op-alloy-rpc-types-engine = { version =  "0.9.0", default-features = false }
-maili-rpc = { version =  "0.1.6", default-features = false }
 op-alloy-network = { version =  "0.9.0", default-features = false }
 op-alloy-consensus = { version =  "0.9.0", default-features = false }
+## op-maili
+maili-rpc = { version =  "0.1.6", default-features = false }
+maili-flz = { version =  "0.1.6", default-features = false }
 
 # misc
 aquamarine = "0.6"
diff --git a/crates/optimism/node/Cargo.toml b/crates/optimism/node/Cargo.toml
index 8a597b9ae8a7..3910b7feccbb 100644
--- a/crates/optimism/node/Cargo.toml
+++ b/crates/optimism/node/Cargo.toml
@@ -52,6 +52,7 @@ alloy-eips.workspace = true
 alloy-primitives.workspace = true
 op-alloy-consensus.workspace = true
 op-alloy-rpc-types-engine.workspace = true
+maili-flz.workspace = true
 alloy-rpc-types-engine.workspace = true
 alloy-consensus.workspace = true
 
diff --git a/crates/optimism/node/src/txpool.rs b/crates/optimism/node/src/txpool.rs
index e2f50cb09d98..51506e7a90d0 100644
--- a/crates/optimism/node/src/txpool.rs
+++ b/crates/optimism/node/src/txpool.rs
@@ -45,7 +45,7 @@ pub struct OpPooledTransaction {
     #[deref]
     inner: EthPooledTransaction<OpTransactionSigned>,
     /// The estimated size of this transaction, lazily computed.
-    estimated_tx_compressed_size: OnceLock<u32>,
+    estimated_tx_compressed_size: OnceLock<u64>,
 }
 
 impl OpPooledTransaction {
@@ -58,14 +58,25 @@ impl OpPooledTransaction {
     }
 
     /// Returns the estimated compressed size of a transaction in bytes scaled by 1e6.
-    // This value is computed based on the following formula:
-    // `max(minTransactionSize, intercept + fastlzCoef*fastlzSize)`
-    pub fn estimated_compressed_size(&self) -> u32 {
-        // TODO(mattsse): use standalone flz compute function
-        *self.estimated_tx_compressed_size.get_or_init(|| self.inner.encoded_length as u32)
+    /// This value is computed based on the following formula:
+    /// `max(minTransactionSize, intercept + fastlzCoef*fastlzSize)`
+    pub fn estimated_compressed_size(&self) -> u64 {
+        *self
+            .estimated_tx_compressed_size
+            .get_or_init(|| tx_estimated_size_fjord(&self.inner.transaction().encoded_2718()))
     }
 }
 
+/// Calculate the estimated compressed transaction size in bytes, scaled by 1e6.
+/// This value is computed based on the following formula:
+/// max(minTransactionSize, intercept + fastlzCoef*fastlzSize)
+// TODO(mattsse): replace with library fn from revm or maili once available
+fn tx_estimated_size_fjord(input: &[u8]) -> u64 {
+    let fastlz_size = maili_flz::flz_compress_len(input) as u64;
+
+    fastlz_size.saturating_mul(836_500).saturating_sub(42_585_600).max(100_000_000)
+}
+
 impl From<RecoveredTx<op_alloy_consensus::OpPooledTransaction>> for OpPooledTransaction {
     fn from(tx: RecoveredTx<op_alloy_consensus::OpPooledTransaction>) -> Self {
         let encoded_len = tx.encode_2718_len();