diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index 8fac904..fc437c8 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -13,6 +13,7 @@ env:
   BITCOIND_PASS: dlcdevkit
   ESPLORA_HOST: http://localhost:30000
   RPC_WALLET: ddk
+  NB_CONFIRMATIONS: 6
 
 jobs:
   clippy:
diff --git a/ddk/src/chain/esplora.rs b/ddk/src/chain/esplora.rs
index 38dd935..ae6e408 100644
--- a/ddk/src/chain/esplora.rs
+++ b/ddk/src/chain/esplora.rs
@@ -163,10 +163,12 @@ impl ddk_manager::Blockchain for EsploraClient {
             .get_height()
             .await
             .map_err(esplora_err_to_manager_err)?;
-
         if txn.confirmed {
             match txn.block_height {
-                Some(height) => Ok(tip_height - height),
+                Some(height) => Ok(tip_height
+                    .checked_sub(height)
+                    .map(|diff| diff + 1)
+                    .unwrap_or(0)),
                 None => Ok(0),
             }
         } else {