diff --git a/src/core/operations/BLAKE2b.mjs b/src/core/operations/BLAKE2b.mjs
index 6218f7f08..22b7f06c4 100644
--- a/src/core/operations/BLAKE2b.mjs
+++ b/src/core/operations/BLAKE2b.mjs
@@ -32,8 +32,10 @@ class BLAKE2b extends Operation {
         this.args = [
             {
                 "name": "Size",
-                "type": "option",
-                "value": ["512", "384", "256", "160", "128"]
+                "type": "number",
+                "value": 256,
+                "min": 8,
+                "max": 512
             }, {
                 "name": "Output Encoding",
                 "type": "option",
@@ -61,6 +63,10 @@ class BLAKE2b extends Operation {
             throw new OperationError(["Key cannot be greater than 64 bytes", "It is currently " + key.length + " bytes."].join("\n"));
         }
 
+        if (outSize % 8 !== 0 || outSize < 8 || outSize > 512) {
+            throw new OperationError("Size has to be between 8 to 512 and multiple of 8.");
+        }
+
         input = new Uint8Array(input);
         switch (outFormat) {
             case "Hex":
diff --git a/src/core/operations/BLAKE2s.mjs b/src/core/operations/BLAKE2s.mjs
index 8f84e0414..48c41a6c4 100644
--- a/src/core/operations/BLAKE2s.mjs
+++ b/src/core/operations/BLAKE2s.mjs
@@ -32,8 +32,10 @@ class BLAKE2s extends Operation {
         this.args = [
             {
                 "name": "Size",
-                "type": "option",
-                "value": ["256", "160", "128"]
+                "type": "number",
+                "value": 256,
+                "min": 8,
+                "max": 256
             }, {
                 "name": "Output Encoding",
                 "type": "option",
@@ -62,6 +64,10 @@ class BLAKE2s extends Operation {
             throw new OperationError(["Key cannot be greater than 32 bytes", "It is currently " + key.length + " bytes."].join("\n"));
         }
 
+        if (outSize % 8 !== 0 || outSize < 8 || outSize > 256) {
+            throw new OperationError("Size has to be between 8 to 256 and multiple of 8.");
+        }
+
         input = new Uint8Array(input);
         switch (outFormat) {
             case "Hex":
diff --git a/tests/operations/tests/BLAKE2b.mjs b/tests/operations/tests/BLAKE2b.mjs
index 088b1078c..d25ef0b0b 100644
--- a/tests/operations/tests/BLAKE2b.mjs
+++ b/tests/operations/tests/BLAKE2b.mjs
@@ -52,5 +52,23 @@ TestRegister.addTests([
             { "op": "BLAKE2b",
                 "args": ["128", "Hex", {string: "pseudorandom key", option: "UTF8"}] }
         ]
+    },
+    {
+        name: "BLAKE2b: 224 - Hello World",
+        input: "Hello World",
+        expectedOutput: "19790463ef4ad09bdb724e3a6550c640593d4870f6e192ac8147f35d",
+        recipeConfig: [
+            { "op": "BLAKE2b",
+                "args": ["224", "Hex", {string: "", option: "UTF8"}] }
+        ]
+    },
+    {
+        name: "BLAKE2b: 192 - Hello World",
+        input: "Hello World",
+        expectedOutput: "317d59b18418b8a12623faf5ebc2072e5e70ac4b8ba6d33a",
+        recipeConfig: [
+            { "op": "BLAKE2b",
+                "args": ["192", "Hex", {string: "", option: "UTF8"}] }
+        ]
     }
 ]);
diff --git a/tests/operations/tests/BLAKE2s.mjs b/tests/operations/tests/BLAKE2s.mjs
index fe978d248..7d01a9deb 100755
--- a/tests/operations/tests/BLAKE2s.mjs
+++ b/tests/operations/tests/BLAKE2s.mjs
@@ -43,5 +43,23 @@ TestRegister.addTests([
             { "op": "BLAKE2s",
                 "args": ["128", "Hex", {string: "", option: "UTF8"}] }
         ]
+    },
+    {
+        name: "BLAKE2s: 224 - Hello World",
+        input: "Hello World",
+        expectedOutput: "8a74d9e5c5de9c8a0cb1c292f65808831717e422302f3d58853d58ed",
+        recipeConfig: [
+            { "op": "BLAKE2s",
+                "args": ["224", "Hex", {string: "", option: "UTF8"}] }
+        ]
+    },
+    {
+        name: "BLAKE2s: 192 - Hello World",
+        input: "Hello World",
+        expectedOutput: "cc181c0f167a1727308d894c6182bbe6c4865698e7f7bfac",
+        recipeConfig: [
+            { "op": "BLAKE2s",
+                "args": ["192", "Hex", {string: "", option: "UTF8"}] }
+        ]
     }
 ]);