diff --git a/contracts/igps/core/src/error.rs b/contracts/igps/core/src/error.rs
index 1a8ebb72..7eb7c07c 100644
--- a/contracts/igps/core/src/error.rs
+++ b/contracts/igps/core/src/error.rs
@@ -1,3 +1,5 @@
+use cosmwasm_std::{Coin, Uint256};
+
 #[derive(thiserror::Error, Debug, PartialEq)]
 pub enum ContractError {
     #[error("{0}")]
@@ -12,8 +14,11 @@ pub enum ContractError {
     #[error("unauthorized")]
     Unauthorized {},
 
-    #[error("insufficient funds")]
-    InsufficientFunds {},
+    #[error("insufficient funds: needed {gas_needed:?}, but only received {received:?}")]
+    InsufficientFunds {
+        received: Uint256,
+        gas_needed: Uint256,
+    },
 
     #[error("gas oracle not found for {0}")]
     GasOracleNotFound(u32),
diff --git a/contracts/igps/core/src/execute.rs b/contracts/igps/core/src/execute.rs
index ba375d03..c8dd1c64 100644
--- a/contracts/igps/core/src/execute.rs
+++ b/contracts/igps/core/src/execute.rs
@@ -97,7 +97,13 @@ pub fn pay_for_gas(
     let gas_token = GAS_TOKEN.load(deps.storage)?;
     let received = Uint256::from(cw_utils::must_pay(&info, &gas_token)?);
     let gas_needed = quote_gas_price(deps.storage, &deps.querier, dest_domain, gas_amount)?;
-    ensure!(received >= gas_needed, ContractError::InsufficientFunds {});
+    ensure!(
+        received >= gas_needed,
+        ContractError::InsufficientFunds {
+            received,
+            gas_needed,
+        }
+    );
 
     let payment_gap = Uint128::from_str(&(received - gas_needed).to_string())?;