diff --git a/app/controllers/utils.js b/app/controllers/utils.js
index b7f0ce769..63ca715db 100644
--- a/app/controllers/utils.js
+++ b/app/controllers/utils.js
@@ -4,21 +4,18 @@
  * Module dependencies.
  */
 
-var Utils = require('../models/Utils'),
-  common = require('./common');
+var _ = require('lodash');
+
+var Utils = require('../models/Utils');
+var common = require('./common');
 
 exports.estimateFee = function(req, res) {
+  var args = req.query.nbBlocks || '2';
+  var nbBlocks = args.split(',');
 
-  var nbBlocks = +req.query.nbBlocks || 2;
   var utilsObject = new Utils();
-
-  var returnJsonp = function(err) {
-    if (err || !utilsObject)
-      return common.handleErrors(err, res);
-    else {
-      res.jsonp(utilsObject);
-    }
-  };
-
-  utilsObject.estimateFee(nbBlocks, returnJsonp);
+  utilsObject.estimateFee(nbBlocks, function(err, fees) {
+    if (err) return common.handleErrors(err, res);
+    res.jsonp(fees);
+  });
 };
diff --git a/app/models/Utils.js b/app/models/Utils.js
index ab51deea5..9f9e88467 100644
--- a/app/models/Utils.js
+++ b/app/models/Utils.js
@@ -1,5 +1,7 @@
 'use strict';
 //var imports       = require('soop').imports();
+var _ = require('lodash');
+var async = require('async');
 
 var bitcore = require('bitcore');
 var RpcClient = bitcore.RpcClient;
@@ -8,14 +10,16 @@ var rpc = new RpcClient(config.bitcoind);
 
 function Utils() {}
 
-Utils.prototype.estimateFee = function(n, next) {
+Utils.prototype.estimateFee = function(nbBlocks, cb) {
   var that = this;
 
-  rpc.estimateFee(n, function(err, info) {
-    if (err) return next(err);
-
-    that.feePerKB = info.result;
-    return next();
+  async.map([].concat(nbBlocks), function(n, next) {
+    rpc.estimateFee(+n, function(err, info) {
+      return next(err, [n, info.result]);
+    });
+  }, function(err, result) {
+    if (err) return cb(err);
+    return cb(null, _.zipObject(result));
   });
 };