diff --git a/electrum/commands.py b/electrum/commands.py
index 3159f4ed5..b72d937fd 100644
--- a/electrum/commands.py
+++ b/electrum/commands.py
@@ -1199,7 +1199,7 @@ class Commands:
         else:
             lightning_amount_sat = satoshis(lightning_amount)
             claim_fee = sm.get_claim_fee()
-            onchain_amount_sat = satoshis(onchain_amount + claim_fee)
+            onchain_amount_sat = satoshis(onchain_amount) + claim_fee
             success = await wallet.lnworker.swap_manager.reverse_swap(
                 lightning_amount_sat=lightning_amount_sat,
                 expected_onchain_amount_sat=onchain_amount_sat,