diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 88f1337312..eff3b412be 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -1999,11 +1999,9 @@ bool CWallet::DummySignTx(CMutableTransaction &txNew, const std::vector<CTxOut>
 int64_t CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *wallet, bool use_max_sig)
 {
     std::vector<CTxOut> txouts;
-    // Look up the inputs.  We should have already checked that this transaction
-    // IsAllFromMe(ISMINE_SPENDABLE), so every input should already be in our
-    // wallet, with a valid index into the vout array, and the ability to sign.
     for (const CTxIn& input : tx.vin) {
         const auto mi = wallet->mapWallet.find(input.prevout.hash);
+        // Can not estimate size without knowing the input details
         if (mi == wallet->mapWallet.end()) {
             return -1;
         }
@@ -2018,8 +2016,6 @@ int64_t CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *wall
 {
     CMutableTransaction txNew(tx);
     if (!wallet->DummySignTx(txNew, txouts, use_max_sig)) {
-        // This should never happen, because IsAllFromMe(ISMINE_SPENDABLE)
-        // implies that we can sign for every input.
         return -1;
     }
     return ::GetSerializeSize(txNew, SER_NETWORK, PROTOCOL_VERSION);