diff --git a/migrate/walletdb3to4.js b/migrate/walletdb3to4.js
new file mode 100644
index 00000000..1d320e5a
--- /dev/null
+++ b/migrate/walletdb3to4.js
@@ -0,0 +1,122 @@
+var assert = require('assert');
+var bcoin = require('../');
+var constants = require('../lib/protocol/constants');
+var WalletDB = require('../lib/wallet/walletdb');
+var TXDB = require('../lib/wallet/txdb');
+var BufferWriter = require('../lib/utils/writer');
+var utils = require('../lib/utils/utils');
+var co = bcoin.co;
+var layout = WalletDB.layout;
+var tlayout = TXDB.layout;
+var file = process.argv[2];
+var db, batch;
+
+assert(typeof file === 'string', 'Please pass in a database path.');
+
+file = file.replace(/\.ldb\/?$/, '');
+
+db = bcoin.ldb({
+  location: file,
+  db: 'leveldb',
+  compression: true,
+  cacheSize: 16 << 20,
+  writeBufferSize: 8 << 20,
+  createIfMissing: false,
+  bufferKeys: true
+});
+
+var updateVersion = co(function* updateVersion() {
+  var bak = process.env.HOME + '/walletdb-bak-' + Date.now() + '.ldb';
+  var data, ver;
+
+  console.log('Checking version.');
+
+  data = yield db.get('V');
+  assert(data, 'No version.');
+
+  ver = data.readUInt32LE(0, true);
+
+  if (ver !== 3)
+    throw Error('DB is version ' + ver + '.');
+
+  console.log('Backing up DB to: %s.', bak);
+
+  yield db.backup(bak);
+
+  ver = new Buffer(4);
+  ver.writeUInt32LE(4, 0, true);
+  batch.put('V', ver);
+});
+
+var updateState = co(function* updateState(wid) {
+  var total = 0;
+  var unconfirmed = 0;
+  var confirmed = 0;
+  var txs = 0;
+  var coins = 0;
+  var p, keys;
+
+  keys = yield db.keys({
+    gte: tlayout.prefix(wid, tlayout.t(constants.NULL_HASH)),
+    lte: tlayout.prefix(wid, tlayout.t(constants.HIGH_HASH))
+  });
+
+  txs += keys.length;
+
+  yield db.range({
+    gte: tlayout.prefix(wid, tlayout.c(constants.NULL_HASH, 0x00000000)),
+    lte: tlayout.prefix(wid, tlayout.c(constants.HIGH_HASH, 0xffffffff)),
+    parse: function(key, data) {
+      var height = data.readUInt32LE(4, true);
+      var value = utils.read64N(data, 8);
+
+      total += value;
+
+      if (height === 0x7fffffff)
+        unconfirmed += value;
+      else
+        confirmed += value;
+
+      coins += 1;
+    }
+  });
+
+  p = new BufferWriter();
+  p.writeU64(txs);
+  p.writeU64(coins);
+  p.writeU64(unconfirmed);
+  p.writeU64(confirmed);
+
+  batch.put(tlayout.prefix(wid, tlayout.R), p.render());
+});
+
+var updateStates = co(function* updateStates() {
+  var i, wallets, wid;
+
+  wallets = yield db.keys({
+    gte: layout.w(0),
+    lte: layout.w(0xffffffff),
+    parse: layout.pre
+  });
+
+  console.log('Updating states...');
+
+  for (i = 0; i < wallets.length; i++) {
+    wid = wallets[i];
+    yield updateState(wid);
+  }
+
+  console.log('Updated %d states.', wallets.length);
+});
+
+co.spawn(function* () {
+  yield db.open();
+  batch = db.batch();
+  console.log('Opened %s.', file);
+  yield updateVersion();
+  yield updateStates();
+  yield batch.write();
+}).then(function() {
+  console.log('Migration complete.');
+  process.exit(0);
+});