diff --git a/lib/model/txproposal.js b/lib/model/txproposal.js
index 0e8f0b8..0ec513f 100644
--- a/lib/model/txproposal.js
+++ b/lib/model/txproposal.js
@@ -109,6 +109,10 @@ TxProposal.fromObj = function(obj) {
   return x;
 };
 
+TxProposal.prototype.setInputs = function(inputs) {
+  this.inputs = inputs;
+  this.inputPaths = _.pluck(inputs, 'path');
+};
 
 TxProposal.prototype._updateStatus = function() {
   if (this.status != 'pending') return;
diff --git a/lib/server.js b/lib/server.js
index f73b727..4cf3db7 100644
--- a/lib/server.js
+++ b/lib/server.js
@@ -602,7 +602,9 @@ WalletService.prototype._getUtxos = function(cb) {
         return cb(new ClientError('BLOCKCHAINERROR', 'Could not fetch unspent outputs'));
       }
       var utxos = _.map(inutxos, function(utxo) {
-        return _.pick(utxo, ['txid', 'vout', 'address', 'scriptPubKey', 'amount', 'satoshis']);
+        var u = _.pick(utxo, ['txid', 'vout', 'address', 'scriptPubKey', 'amount', 'satoshis']);
+        u.locked = false;
+        return u;
       });
       self.getPendingTxs({}, function(err, txps) {
         if (err) return cb(err);
@@ -657,6 +659,31 @@ WalletService.prototype._totalizeUtxos = function(utxos) {
 };
 
 
+WalletService.prototype._computeKbToSendMax = function(utxos, amount, cb) {
+  var self = this;
+
+  var unlockedUtxos = _.filter(utxos, {
+    locked: false
+  });
+  if (_.isEmpty(unlockedUtxos)) return cb(null, 0);
+
+  self.getWallet({}, function(err, wallet) {
+    if (err) return cb(err);
+
+    var t = WalletUtils.newBitcoreTransaction();
+    try {
+      _.each(unlockedUtxos, function(i) {
+        t.from(i, i.publicKeys, wallet.m);
+      });
+      t.to(utxos[0].address, amount);
+      var sizeInKb = Math.ceil(t._estimateSize() / 1000);
+      return cb(null, sizeInKb);
+    } catch (ex) {
+      return cb(ex);
+    }
+  });
+};
+
 /**
  * Creates a new transaction proposal.
  * @param {Object} opts
@@ -686,7 +713,13 @@ WalletService.prototype.getBalance = function(opts, cb) {
 
     balance.byAddress = _.values(byAddress);
 
-    return cb(null, balance);
+    self._computeKbToSendMax(utxos, balance.totalAmount - balance.lockedAmount, function(err, sizeInKb) {
+      if (err) {
+        log.error('Could not compute fees needed to transfer max amount', err);
+      }
+      balance.totalKbToSendMax = sizeInKb || 0;
+      return cb(null, balance);
+    });
   });
 };
 
@@ -720,13 +753,12 @@ WalletService.prototype._selectTxInputs = function(txp, cb) {
 
       if (total >= txp.getTotalAmount()) {
         try {
-          txp.inputs = selected;
+          txp.setInputs(selected);
           bitcoreTx = txp.getBitcoreTx();
           bitcoreError = bitcoreTx.getSerializationError({
             disableIsFullySigned: true,
           });
           if (!bitcoreError) {
-            txp.inputPaths = _.pluck(txp.inputs, 'path');
             txp.fee = bitcoreTx.getFee();
             return cb();
           }
diff --git a/package.json b/package.json
index c5d6a4f..1881518 100644
--- a/package.json
+++ b/package.json
@@ -2,7 +2,7 @@
   "name": "bitcore-wallet-service",
   "description": "A service for Mutisig HD Bitcoin Wallets",
   "author": "BitPay Inc",
-  "version": "0.0.35",
+  "version": "0.0.36",
   "keywords": [
     "bitcoin",
     "copay",
diff --git a/test/integration/server.js b/test/integration/server.js
index 066bd2d..7d19661 100644
--- a/test/integration/server.js
+++ b/test/integration/server.js
@@ -1144,6 +1144,7 @@ describe('Wallet service', function() {
           should.exist(balance);
           balance.totalAmount.should.equal(helpers.toSatoshi(6));
           balance.lockedAmount.should.equal(0);
+          balance.totalKbToSendMax.should.equal(1);
           should.exist(balance.byAddress);
           balance.byAddress.length.should.equal(2);
           balance.byAddress[0].amount.should.equal(helpers.toSatoshi(4));
@@ -1163,6 +1164,7 @@ describe('Wallet service', function() {
         should.exist(balance);
         balance.totalAmount.should.equal(0);
         balance.lockedAmount.should.equal(0);
+        balance.totalKbToSendMax.should.equal(0);
         should.exist(balance.byAddress);
         balance.byAddress.length.should.equal(0);
         done();
@@ -1177,6 +1179,7 @@ describe('Wallet service', function() {
           should.exist(balance);
           balance.totalAmount.should.equal(0);
           balance.lockedAmount.should.equal(0);
+          balance.totalKbToSendMax.should.equal(0);
           should.exist(balance.byAddress);
           balance.byAddress.length.should.equal(0);
           done();
@@ -1197,6 +1200,18 @@ describe('Wallet service', function() {
         });
       });
     });
+    it('should return correct kb to send max', function(done) {
+      helpers.stubUtxos(server, wallet, _.range(1, 10, 0), function() {
+        server.getBalance({}, function(err, balance) {
+          should.not.exist(err);
+          should.exist(balance);
+          balance.totalAmount.should.equal(helpers.toSatoshi(9));
+          balance.lockedAmount.should.equal(0);
+          balance.totalKbToSendMax.should.equal(2);
+          done();
+        });
+      });
+    });
     it('should fail gracefully when blockchain is unreachable', function(done) {
       blockchainExplorer.getUnspentUtxos = sinon.stub().callsArgWith(1, 'dummy error');
       server.createAddress({}, function(err, address) {
@@ -1688,6 +1703,57 @@ describe('Wallet service', function() {
         });
       });
     });
+
+    it('should be able to send max amount', function(done) {
+      helpers.stubUtxos(server, wallet, _.range(1, 10, 0), function() {
+        server.getBalance({}, function(err, balance) {
+          should.not.exist(err);
+          balance.totalAmount.should.equal(helpers.toSatoshi(9));
+          balance.lockedAmount.should.equal(0);
+          balance.totalKbToSendMax.should.equal(3);
+          var max = (balance.totalAmount - balance.lockedAmount) - (balance.totalKbToSendMax * 10000);
+          var txOpts = helpers.createProposalOpts('18PzpUFkFZE8zKWUPvfykkTxmB9oMR8qP7', max / 1e8, null, TestData.copayers[0].privKey_1H_0);
+          server.createTx(txOpts, function(err, tx) {
+            should.not.exist(err);
+            should.exist(tx);
+            tx.amount.should.equal(max);
+            tx.fee.should.equal(3 * 10000);
+            server.getBalance({}, function(err, balance) {
+              should.not.exist(err);
+              balance.lockedAmount.should.equal(helpers.toSatoshi(9));
+              done();
+            });
+          });
+        });
+      });
+    });
+    it('should be able to send max non-locked amount', function(done) {
+      helpers.stubUtxos(server, wallet, _.range(1, 10, 0), function() {
+        var txOpts = helpers.createProposalOpts('18PzpUFkFZE8zKWUPvfykkTxmB9oMR8qP7', 3.5, null, TestData.copayers[0].privKey_1H_0);
+        server.createTx(txOpts, function(err, tx) {
+          should.not.exist(err);
+          server.getBalance({}, function(err, balance) {
+            should.not.exist(err);
+            balance.totalAmount.should.equal(helpers.toSatoshi(9));
+            balance.lockedAmount.should.equal(helpers.toSatoshi(4));
+            balance.totalKbToSendMax.should.equal(2);
+            var max = (balance.totalAmount - balance.lockedAmount) - (balance.totalKbToSendMax * 2000);
+            var txOpts = helpers.createProposalOpts('18PzpUFkFZE8zKWUPvfykkTxmB9oMR8qP7', max / 1e8, null, TestData.copayers[0].privKey_1H_0, 2000);
+            server.createTx(txOpts, function(err, tx) {
+              should.not.exist(err);
+              should.exist(tx);
+              tx.amount.should.equal(max);
+              tx.fee.should.equal(2 * 2000);
+              server.getBalance({}, function(err, balance) {
+                should.not.exist(err);
+                balance.lockedAmount.should.equal(helpers.toSatoshi(9));
+                done();
+              });
+            });
+          });
+        });
+      });
+    });
   });
 
   describe('#createTx backoff time', function(done) {