diff --git a/ethers/provider.nim b/ethers/provider.nim
index db7f0a4..33c2038 100644
--- a/ethers/provider.nim
+++ b/ethers/provider.nim
@@ -230,22 +230,27 @@ proc confirm*(
   {.async: (raises: [CancelledError, ProviderError, EthersError]).} =
 
   ## Waits for a transaction to be mined and for the specified number of blocks
-  ## to pass since it was mined (confirmations).
+  ## to pass since it was mined (confirmations). The number of confirmations
+  ## includes the block in which the transaction was mined.
   ## A timeout, in blocks, can be specified that will raise an error if too many
   ## blocks have passed without the tx having been mined.
 
+  assert confirmations > 0
+
   var blockNumber: UInt256
   let blockEvent = newAsyncEvent()
 
-  proc onBlockNumber(number: UInt256) =
-    blockNumber = number
-    blockEvent.fire()
+  proc updateBlockNumber {.async: (raises: [ProviderError]).} =
+    let number = await tx.provider.getBlockNumber()
+    if number > blockNumber:
+      blockNumber = number
+      blockEvent.fire()
 
-  proc onBlock(blck: Block) =
-    if number =? blck.number:
-      onBlockNumber(number)
+  proc onBlock(_: Block) =
+    # ignore block parameter; hardhat may call this with pending blocks
+    asyncSpawn updateBlockNumber()
 
-  onBlockNumber(await tx.provider.getBlockNumber())
+  await updateBlockNumber()
   let subscription = await tx.provider.subscribe(onBlock)
 
   let finish = blockNumber + timeout.u256
diff --git a/testmodule/providers/jsonrpc/testJsonRpcProvider.nim b/testmodule/providers/jsonrpc/testJsonRpcProvider.nim
index 0f6e435..90a28ff 100644
--- a/testmodule/providers/jsonrpc/testJsonRpcProvider.nim
+++ b/testmodule/providers/jsonrpc/testJsonRpcProvider.nim
@@ -68,13 +68,13 @@ for url in ["ws://" & providerUrl, "http://"  & providerUrl]:
       check UInt256.fromHex("0x" & txResp.hash.toHex) > 0
 
     test "can wait for a transaction to be confirmed":
-      for confirmations in 0..3:
+      for confirmations in 1..3:
         let signer = provider.getSigner()
         let transaction = Transaction.example
         let populated = await signer.populateTransaction(transaction)
         let confirming = signer.sendTransaction(populated).confirm(confirmations)
         await sleepAsync(100.millis) # wait for tx to be mined
-        await provider.mineBlocks(confirmations - 1)
+        await provider.mineBlocks(confirmations)
         let receipt = await confirming
         check receipt.blockNumber.isSome
 
diff --git a/testmodule/testContracts.nim b/testmodule/testContracts.nim
index 0981f1d..4eac40e 100644
--- a/testmodule/testContracts.nim
+++ b/testmodule/testContracts.nim
@@ -305,11 +305,11 @@ for url in ["ws://"  & providerUrl, "http://"  & providerUrl]:
         executeTx(),
         executeTx()
       )
-      let receipt1 = await futs[1].confirm(0)
-      let receipt2 = await futs[2].confirm(0)
+      let receipt1 = await futs[1].confirm(1)
+      let receipt2 = await futs[2].confirm(1)
 
       check receipt1.status == TransactionStatus.Success
       check receipt2.status == TransactionStatus.Success
 
       let balanceAfter = await token.myBalance()
-      check balanceAfter == balanceBefore + 200.u256
\ No newline at end of file
+      check balanceAfter == balanceBefore + 200.u256
diff --git a/testmodule/testCustomErrors.nim b/testmodule/testCustomErrors.nim
index 9038c5e..7b19f5f 100644
--- a/testmodule/testCustomErrors.nim
+++ b/testmodule/testCustomErrors.nim
@@ -136,7 +136,7 @@ suite "Contract custom errors":
 
     let contract = contract.connect(provider.getSigner())
     try:
-      let future = contract.revertsTransaction(overrides = overrides).confirm(0)
+      let future = contract.revertsTransaction(overrides = overrides).confirm(1)
       await sleepAsync(100.millis) # wait for transaction to be submitted
       discard await provider.send("evm_mine", @[]) # mine the transaction
       discard await future # wait for confirmation