diff --git a/bus-mapping/src/circuit_input_builder.rs b/bus-mapping/src/circuit_input_builder.rs
index b2b5c20560..5d3c1b582f 100644
--- a/bus-mapping/src/circuit_input_builder.rs
+++ b/bus-mapping/src/circuit_input_builder.rs
@@ -346,7 +346,11 @@ impl CircuitInputBuilder<DynamicCParams> {
                 .transactions
                 .iter()
                 .fold(0, |acc, tx| acc + tx.input.len());
-            let max_exp_steps = self.block.exp_events.len();
+            let max_exp_steps = self
+                .block
+                .exp_events
+                .iter()
+                .fold(0usize, |acc, e| acc + e.steps.len());
             // The `+ 2` is used to take into account the two extra empty copy rows needed
             // to satisfy the query at `Rotation(2)` performed inside of the
             // `rows[2].value == rows[0].value * r + rows[1].value` requirement in the RLC