diff --git a/src/blockchain_db/blockchain_db.h b/src/blockchain_db/blockchain_db.h
index 7870a2efd..f13aa0cae 100644
--- a/src/blockchain_db/blockchain_db.h
+++ b/src/blockchain_db/blockchain_db.h
@@ -1404,6 +1404,13 @@ public:
    */
   virtual cryptonote::blobdata get_txpool_tx_blob(const crypto::hash& txid) const = 0;
 
+  /**
+   * @brief prune output data for the given amount
+   *
+   * @param amount the amount for which to prune data
+   */
+  virtual void prune_outputs(uint64_t amount) = 0;
+
   /**
    * @brief runs a function over all txpool transactions
    *
diff --git a/src/blockchain_db/lmdb/db_lmdb.cpp b/src/blockchain_db/lmdb/db_lmdb.cpp
index 5af5d1903..4bfc80863 100644
--- a/src/blockchain_db/lmdb/db_lmdb.cpp
+++ b/src/blockchain_db/lmdb/db_lmdb.cpp
@@ -1075,6 +1075,60 @@ void BlockchainLMDB::remove_output(const uint64_t amount, const uint64_t& out_in
     throw0(DB_ERROR(lmdb_error(std::string("Error deleting amount for output index ").append(boost::lexical_cast<std::string>(out_index).append(": ")).c_str(), result).c_str()));
 }
 
+void BlockchainLMDB::prune_outputs(uint64_t amount)
+{
+  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+  check_open();
+  mdb_txn_cursors *m_cursors = &m_wcursors;
+  CURSOR(output_amounts);
+  CURSOR(output_txs);
+
+  MINFO("Pruning outputs for amount " << amount);
+
+  MDB_val v;
+  MDB_val_set(k, amount);
+  int result = mdb_cursor_get(m_cur_output_amounts, &k, &v, MDB_SET);
+  if (result == MDB_NOTFOUND)
+    return;
+  if (result)
+    throw0(DB_ERROR(lmdb_error("Error looking up outputs: ", result).c_str()));
+
+  // gather output ids
+  mdb_size_t num_elems;
+  mdb_cursor_count(m_cur_output_amounts, &num_elems);
+  MINFO(num_elems << " outputs found");
+  std::vector<uint64_t> output_ids;
+  output_ids.reserve(num_elems);
+  while (1)
+  {
+    const pre_rct_outkey *okp = (const pre_rct_outkey *)v.mv_data;
+    output_ids.push_back(okp->output_id);
+    MDEBUG("output id " << okp->output_id);
+    result = mdb_cursor_get(m_cur_output_amounts, &k, &v, MDB_NEXT_DUP);
+    if (result == MDB_NOTFOUND)
+      break;
+    if (result)
+      throw0(DB_ERROR(lmdb_error("Error counting outputs: ", result).c_str()));
+  }
+  if (output_ids.size() != num_elems)
+    throw0(DB_ERROR("Unexpected number of outputs"));
+
+  result = mdb_cursor_del(m_cur_output_amounts, MDB_NODUPDATA);
+  if (result)
+    throw0(DB_ERROR(lmdb_error("Error deleting outputs: ", result).c_str()));
+
+  for (uint64_t output_id: output_ids)
+  {
+    MDB_val_set(v, output_id);
+    result = mdb_cursor_get(m_cur_output_txs, (MDB_val *)&zerokval, &v, MDB_GET_BOTH);
+    if (result)
+      throw0(DB_ERROR(lmdb_error("Error looking up output: ", result).c_str()));
+    result = mdb_cursor_del(m_cur_output_txs, 0);
+    if (result)
+      throw0(DB_ERROR(lmdb_error("Error deleting output: ", result).c_str()));
+  }
+}
+
 void BlockchainLMDB::add_spent_key(const crypto::key_image& k_image)
 {
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
@@ -2229,11 +2283,19 @@ uint64_t BlockchainLMDB::num_outputs() const
   TXN_PREFIX_RDONLY();
   int result;
 
-  // get current height
-  MDB_stat db_stats;
-  if ((result = mdb_stat(m_txn, m_output_txs, &db_stats)))
+  RCURSOR(output_txs)
+
+  uint64_t num = 0;
+  MDB_val k, v;
+  result = mdb_cursor_get(m_cur_output_txs, &k, &v, MDB_LAST);
+  if (result == MDB_NOTFOUND)
+    num = 0;
+  else if (result == 0)
+    num = 1 + ((const outtx*)v.mv_data)->output_id;
+  else
     throw0(DB_ERROR(lmdb_error("Failed to query m_output_txs: ", result).c_str()));
-  return db_stats.ms_entries;
+
+  return num;
 }
 
 bool BlockchainLMDB::tx_exists(const crypto::hash& h) const
diff --git a/src/blockchain_db/lmdb/db_lmdb.h b/src/blockchain_db/lmdb/db_lmdb.h
index 26159ab4d..6db241240 100644
--- a/src/blockchain_db/lmdb/db_lmdb.h
+++ b/src/blockchain_db/lmdb/db_lmdb.h
@@ -345,6 +345,8 @@ private:
 
   void remove_output(const uint64_t amount, const uint64_t& out_index);
 
+  virtual void prune_outputs(uint64_t amount);
+
   virtual void add_spent_key(const crypto::key_image& k_image);
 
   virtual void remove_spent_key(const crypto::key_image& k_image);
diff --git a/src/blockchain_utilities/CMakeLists.txt b/src/blockchain_utilities/CMakeLists.txt
index c9ad1cebe..ddf575c29 100644
--- a/src/blockchain_utilities/CMakeLists.txt
+++ b/src/blockchain_utilities/CMakeLists.txt
@@ -81,6 +81,17 @@ monero_private_headers(blockchain_usage
 
 
 
+set(blockchain_prune_known_spent_data_sources
+  blockchain_prune_known_spent_data.cpp
+  )
+
+set(blockchain_prune_known_spent_data_private_headers)
+
+monero_private_headers(blockchain_prune_known_spent_data
+	  ${blockchain_prune_known_spent_data_private_headers})
+
+
+
 set(blockchain_ancestry_sources
   blockchain_ancestry.cpp
   )
@@ -265,3 +276,25 @@ set_property(TARGET blockchain_stats
 	PROPERTY
 	OUTPUT_NAME "monero-blockchain-stats")
 install(TARGETS blockchain_stats DESTINATION bin)
+
+monero_add_executable(blockchain_prune_known_spent_data
+  ${blockchain_prune_known_spent_data_sources}
+  ${blockchain_prune_known_spent_data_private_headers})
+
+target_link_libraries(blockchain_prune_known_spent_data
+  PRIVATE
+    cryptonote_core
+    blockchain_db
+    p2p
+    version
+    epee
+    ${Boost_FILESYSTEM_LIBRARY}
+    ${Boost_SYSTEM_LIBRARY}
+    ${Boost_THREAD_LIBRARY}
+    ${CMAKE_THREAD_LIBS_INIT}
+    ${EXTRA_LIBRARIES})
+
+set_property(TARGET blockchain_prune_known_spent_data
+	PROPERTY
+	OUTPUT_NAME "monero-blockchain-prune-known-spent-data")
+install(TARGETS blockchain_prune_known_spent_data DESTINATION bin)
diff --git a/src/blockchain_utilities/blockchain_prune_known_spent_data.cpp b/src/blockchain_utilities/blockchain_prune_known_spent_data.cpp
new file mode 100644
index 000000000..f6136c1ba
--- /dev/null
+++ b/src/blockchain_utilities/blockchain_prune_known_spent_data.cpp
@@ -0,0 +1,305 @@
+// Copyright (c) 2014-2018, The Monero Project
+//
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <boost/algorithm/string.hpp>
+#include "common/command_line.h"
+#include "serialization/crypto.h"
+#include "cryptonote_core/tx_pool.h"
+#include "cryptonote_core/cryptonote_core.h"
+#include "cryptonote_core/blockchain.h"
+#include "blockchain_db/blockchain_db.h"
+#include "blockchain_db/db_types.h"
+#include "version.h"
+
+#undef MONERO_DEFAULT_LOG_CATEGORY
+#define MONERO_DEFAULT_LOG_CATEGORY "bcutil"
+
+namespace po = boost::program_options;
+using namespace epee;
+using namespace cryptonote;
+
+static std::map<uint64_t, uint64_t> load_outputs(const std::string &filename)
+{
+  std::map<uint64_t, uint64_t> outputs;
+  uint64_t amount = std::numeric_limits<uint64_t>::max();
+  FILE *f;
+
+  f = fopen(filename.c_str(), "r");
+  if (!f)
+  {
+    MERROR("Failed to load outputs from " << filename << ": " << strerror(errno));
+    return {};
+  }
+  while (1)
+  {
+    char s[256];
+    if (!fgets(s, sizeof(s), f))
+      break;
+    if (feof(f))
+      break;
+    const size_t len = strlen(s);
+    if (len > 0 && s[len - 1] == '\n')
+      s[len - 1] = 0;
+    if (!s[0])
+      continue;
+    std::pair<uint64_t, uint64_t> output;
+    uint64_t offset, num_offsets;
+    if (sscanf(s, "@%" PRIu64, &amount) == 1)
+    {
+      continue;
+    }
+    if (amount == std::numeric_limits<uint64_t>::max())
+    {
+      MERROR("Bad format in " << filename);
+      continue;
+    }
+    if (sscanf(s, "%" PRIu64 "*%" PRIu64, &offset, &num_offsets) == 2 && num_offsets < std::numeric_limits<uint64_t>::max() - offset)
+    {
+      outputs[amount] += num_offsets;
+    }
+    else if (sscanf(s, "%" PRIu64, &offset) == 1)
+    {
+      outputs[amount] += 1;
+    }
+    else
+    {
+      MERROR("Bad format in " << filename);
+      continue;
+    }
+  }
+  fclose(f);
+  return outputs;
+}
+
+int main(int argc, char* argv[])
+{
+  TRY_ENTRY();
+
+  epee::string_tools::set_module_name_and_folder(argv[0]);
+
+  std::string default_db_type = "lmdb";
+
+  std::string available_dbs = cryptonote::blockchain_db_types(", ");
+  available_dbs = "available: " + available_dbs;
+
+  uint32_t log_level = 0;
+
+  tools::on_startup();
+
+  po::options_description desc_cmd_only("Command line options");
+  po::options_description desc_cmd_sett("Command line options and settings options");
+  const command_line::arg_descriptor<std::string> arg_log_level  = {"log-level",  "0-4 or categories", ""};
+  const command_line::arg_descriptor<std::string> arg_database = {
+    "database", available_dbs.c_str(), default_db_type
+  };
+  const command_line::arg_descriptor<bool> arg_verbose  = {"verbose", "Verbose output", false};
+  const command_line::arg_descriptor<bool> arg_dry_run  = {"dry-run", "Do not actually prune", false};
+  const command_line::arg_descriptor<std::string> arg_input = {"input", "Path to the known spent outputs file"};
+
+  command_line::add_arg(desc_cmd_sett, cryptonote::arg_data_dir);
+  command_line::add_arg(desc_cmd_sett, cryptonote::arg_testnet_on);
+  command_line::add_arg(desc_cmd_sett, cryptonote::arg_stagenet_on);
+  command_line::add_arg(desc_cmd_sett, arg_log_level);
+  command_line::add_arg(desc_cmd_sett, arg_database);
+  command_line::add_arg(desc_cmd_sett, arg_verbose);
+  command_line::add_arg(desc_cmd_sett, arg_dry_run);
+  command_line::add_arg(desc_cmd_sett, arg_input);
+  command_line::add_arg(desc_cmd_only, command_line::arg_help);
+
+  po::options_description desc_options("Allowed options");
+  desc_options.add(desc_cmd_only).add(desc_cmd_sett);
+
+  po::variables_map vm;
+  bool r = command_line::handle_error_helper(desc_options, [&]()
+  {
+    auto parser = po::command_line_parser(argc, argv).options(desc_options);
+    po::store(parser.run(), vm);
+    po::notify(vm);
+    return true;
+  });
+  if (! r)
+    return 1;
+
+  if (command_line::get_arg(vm, command_line::arg_help))
+  {
+    std::cout << "Monero '" << MONERO_RELEASE_NAME << "' (v" << MONERO_VERSION_FULL << ")" << ENDL << ENDL;
+    std::cout << desc_options << std::endl;
+    return 1;
+  }
+
+  mlog_configure(mlog_get_default_log_path("monero-blockchain-prune-known-spent-data.log"), true);
+  if (!command_line::is_arg_defaulted(vm, arg_log_level))
+    mlog_set_log(command_line::get_arg(vm, arg_log_level).c_str());
+  else
+    mlog_set_log(std::string(std::to_string(log_level) + ",bcutil:INFO").c_str());
+
+  LOG_PRINT_L0("Starting...");
+
+  std::string opt_data_dir = command_line::get_arg(vm, cryptonote::arg_data_dir);
+  bool opt_testnet = command_line::get_arg(vm, cryptonote::arg_testnet_on);
+  bool opt_stagenet = command_line::get_arg(vm, cryptonote::arg_stagenet_on);
+  network_type net_type = opt_testnet ? TESTNET : opt_stagenet ? STAGENET : MAINNET;
+  bool opt_verbose = command_line::get_arg(vm, arg_verbose);
+  bool opt_dry_run = command_line::get_arg(vm, arg_dry_run);
+
+  std::string db_type = command_line::get_arg(vm, arg_database);
+  if (!cryptonote::blockchain_valid_db_type(db_type))
+  {
+    std::cerr << "Invalid database type: " << db_type << std::endl;
+    return 1;
+  }
+
+  const std::string input = command_line::get_arg(vm, arg_input);
+
+  LOG_PRINT_L0("Initializing source blockchain (BlockchainDB)");
+  std::unique_ptr<Blockchain> core_storage;
+  tx_memory_pool m_mempool(*core_storage);
+  core_storage.reset(new Blockchain(m_mempool));
+  BlockchainDB *db = new_db(db_type);
+  if (db == NULL)
+  {
+    LOG_ERROR("Attempted to use non-existent database type: " << db_type);
+    throw std::runtime_error("Attempting to use non-existent database type");
+  }
+  LOG_PRINT_L0("database: " << db_type);
+
+  const std::string filename = (boost::filesystem::path(opt_data_dir) / db->get_db_name()).string();
+  LOG_PRINT_L0("Loading blockchain from folder " << filename << " ...");
+
+  try
+  {
+    db->open(filename, 0);
+  }
+  catch (const std::exception& e)
+  {
+    LOG_PRINT_L0("Error opening database: " << e.what());
+    return 1;
+  }
+  r = core_storage->init(db, net_type);
+
+  CHECK_AND_ASSERT_MES(r, 1, "Failed to initialize source blockchain storage");
+  LOG_PRINT_L0("Source blockchain storage initialized OK");
+
+  std::map<uint64_t, uint64_t> known_spent_outputs;
+  if (input.empty())
+  {
+    std::map<uint64_t, std::pair<uint64_t, uint64_t>> outputs;
+
+    LOG_PRINT_L0("Scanning for known spent data...");
+    db->for_all_transactions([&](const crypto::hash &txid, const cryptonote::transaction &tx){
+      const bool miner_tx = tx.vin.size() == 1 && tx.vin[0].type() == typeid(txin_gen);
+      for (const auto &in: tx.vin)
+      {
+        if (in.type() != typeid(txin_to_key))
+          continue;
+        const auto &txin = boost::get<txin_to_key>(in);
+        if (txin.amount == 0)
+          continue;
+
+        outputs[txin.amount].second++;
+      }
+
+      for (const auto &out: tx.vout)
+      {
+        uint64_t amount = out.amount;
+        if (miner_tx && tx.version >= 2)
+          amount = 0;
+        if (amount == 0)
+          continue;
+        if (out.target.type() != typeid(txout_to_key))
+          continue;
+
+        outputs[amount].first++;
+      }
+      return true;
+    }, true);
+
+    for (const auto &i: outputs)
+    {
+      known_spent_outputs[i.first] = i.second.second;
+    }
+  }
+  else
+  {
+    LOG_PRINT_L0("Loading known spent data...");
+    known_spent_outputs = load_outputs(input);
+  }
+
+  LOG_PRINT_L0("Pruning known spent data...");
+
+  bool stop_requested = false;
+  tools::signal_handler::install([&stop_requested](int type) {
+    stop_requested = true;
+  });
+
+  db->batch_start();
+
+  size_t num_total_outputs = 0, num_prunable_outputs = 0, num_known_spent_outputs = 0, num_eligible_outputs = 0, num_eligible_known_spent_outputs = 0;
+  for (auto i = known_spent_outputs.begin(); i != known_spent_outputs.end(); ++i)
+  {
+    uint64_t num_outputs = db->get_num_outputs(i->first);
+    num_total_outputs += num_outputs;
+    num_known_spent_outputs += i->second;
+    if (i->first == 0 || is_valid_decomposed_amount(i->first))
+    {
+      if (opt_verbose)
+        MINFO("Ignoring output value " << i->first << ", with " << num_outputs << " outputs");
+      continue;
+    }
+    num_eligible_outputs += num_outputs;
+    num_eligible_known_spent_outputs += i->second;
+    if (opt_verbose)
+      MINFO(i->first << ": " << i->second << "/" << num_outputs);
+    if (num_outputs > i->second)
+      continue;
+    if (num_outputs && num_outputs < i->second)
+    {
+      MERROR("More outputs are spent than known for amount " << i->first << ", not touching");
+      continue;
+    }
+    if (opt_verbose)
+      MINFO("Pruning data for " << num_outputs << " outputs");
+    if (!opt_dry_run)
+      db->prune_outputs(i->first);
+    num_prunable_outputs += i->second;
+  }
+
+  db->batch_stop();
+
+  MINFO("Total outputs: " << num_total_outputs);
+  MINFO("Known spent outputs: " << num_known_spent_outputs);
+  MINFO("Eligible outputs: " << num_eligible_outputs);
+  MINFO("Eligible known spent outputs: " << num_eligible_known_spent_outputs);
+  MINFO("Prunable outputs: " << num_prunable_outputs);
+
+  LOG_PRINT_L0("Blockchain known spent data pruned OK");
+  core_storage->deinit();
+  return 0;
+
+  CATCH_ENTRY("Error", 1);
+}
diff --git a/tests/unit_tests/testdb.h b/tests/unit_tests/testdb.h
index a9c772920..5d9ba5833 100644
--- a/tests/unit_tests/testdb.h
+++ b/tests/unit_tests/testdb.h
@@ -142,5 +142,6 @@ public:
   virtual bool prune_blockchain(uint32_t pruning_seed = 0) { return true; }
   virtual bool update_pruning() { return true; }
   virtual bool check_pruning() { return true; }
+  virtual void prune_outputs(uint64_t amount) {}
 };