diff --git a/src/main/java/com/github/jfasttext/JFastText.java b/src/main/java/com/github/jfasttext/JFastText.java
index 1f2d333..137ce26 100644
--- a/src/main/java/com/github/jfasttext/JFastText.java
+++ b/src/main/java/com/github/jfasttext/JFastText.java
@@ -58,7 +58,7 @@ public List<String> predict(String text, int k) {
             throw new IllegalArgumentException("k must be positive");
         }
         FastTextWrapper.StringVector sv = fta.predict(text, k);
-        List<String> predictions = new ArrayList<>();
+        List<String> predictions = new ArrayList<>((int) sv.size());
         for (int i = 0; i < sv.size(); i++) {
             predictions.add(sv.get(i).getString());
         }
@@ -75,7 +75,7 @@ public List<ProbLabel> predictProba(String text, int k) {
             throw new IllegalArgumentException("k must be positive");
         }
         FastTextWrapper.FloatStringPairVector fspv = fta.predictProba(text, k);
-        List<ProbLabel> probaPredictions = new ArrayList<>();
+        List<ProbLabel> probaPredictions = new ArrayList<>((int) fspv.size());
         for (int i = 0; i < fspv.size(); i++) {
             float logProb = fspv.first(i);
             String label = fspv.second(i).getString();
@@ -86,7 +86,7 @@ public List<ProbLabel> predictProba(String text, int k) {
 
     public List<Float> getVector(String word) {
         FastTextWrapper.RealVector rv = fta.getVector(word);
-        List<Float> wordVec = new ArrayList<>();
+        List<Float> wordVec = new ArrayList<>((int) rv.size());
         for (int i = 0; i < rv.size(); i++) {
             wordVec.add(rv.get(i));
         }
@@ -178,7 +178,7 @@ public String getPretrainedVectorsFileName() {
     }
 
     private static List<String> stringVec2Strings(FastTextWrapper.StringVector sv) {
-        List<String> strings = new ArrayList<>();
+        List<String> strings = new ArrayList<>((int) sv.size());
         for (int i = 0; i < sv.size(); i++) {
             strings.add(sv.get(i).getString());
         }