diff --git a/lib/bcoin/mtx.js b/lib/bcoin/mtx.js
index 47add704..b5bc3884 100644
--- a/lib/bcoin/mtx.js
+++ b/lib/bcoin/mtx.js
@@ -786,15 +786,12 @@ MTX.prototype.maxSize = function maxSize(maxM, maxN) {
 };
 
 MTX.prototype.selectCoins = function selectCoins(coins, options) {
+  var dustThreshold = constants.tx.dustThreshold;
   var tx = this.clone();
   var outputValue = tx.getOutputValue();
-  var totalkb = 1;
   var chosen = [];
   var lastAdded = 0;
-  var minFee = constants.tx.minFee;
-  var dustThreshold = constants.tx.dustThreshold;
-  var i, size, newkb, change;
-  var fee;
+  var i, size, change, fee;
 
   assert(tx.inputs.length === 0);
 
@@ -856,7 +853,7 @@ MTX.prototype.selectCoins = function selectCoins(coins, options) {
     // Transfer `total` funds maximum.
     addCoins();
   } else {
-    fee = new bn(minFee);
+    fee = new bn(constants.tx.minFee);
 
     // Transfer `total` funds maximum.
     addCoins();
@@ -875,20 +872,17 @@ MTX.prototype.selectCoins = function selectCoins(coins, options) {
       size = tx.maxSize(options.m, options.n);
 
       if (options.free) {
-        if (tx.isFree(null, size)) {
+        if (tx.isFree(network.height + 1, size)) {
           fee = new bn(0);
           break;
         }
         options.free = false;
       }
 
-      if (options.accurate) {
+      if (options.accurate)
         fee = tx.getMinFee(size);
-      } else {
-        newkb = Math.ceil(size / 1024) - totalkb;
-        fee.iaddn(newkb * minFee);
-        totalkb += newkb;
-      }
+      else
+        fee = tx.getMaxFee(size);
 
       // Failed to get enough funds, add more inputs.
       if (!isFull())
@@ -926,13 +920,18 @@ MTX.prototype.selectCoins = function selectCoins(coins, options) {
     }
   }
 
+  if (!chosen) {
+    err = new Error('Could not select coins.');
+    err.requiredFunds = total();
+    throw err;
+  }
+
   // Return necessary inputs and change.
   return {
     coins: chosen,
     change: change,
     fee: fee,
-    total: total(),
-    kb: totalkb
+    total: total()
   };
 };
 
@@ -952,12 +951,6 @@ MTX.prototype.fill = function fill(coins, options) {
 
   result = this.selectCoins(coins, options);
 
-  if (!result.coins) {
-    err = new Error('Could not fill transaction.');
-    err.requiredFunds = result.total;
-    throw err;
-  }
-
   result.coins.forEach(function(coin) {
     self.addInput(coin);
   });