diff --git a/src/core/Utils.mjs b/src/core/Utils.mjs
index ed29ceba..c775aea2 100755
--- a/src/core/Utils.mjs
+++ b/src/core/Utils.mjs
@@ -1206,6 +1206,30 @@ class Utils {
         }[token];
     }
 
+    /**
+     * Iterate object in chunks of given size.
+     *
+     * @param {Iterable} iterable
+     * @param {number} chunksize
+     */
+    static* chunked(iterable, chunksize) {
+        const iterator = iterable[Symbol.iterator]();
+        while (true) {
+            const res = [];
+            for (let i = 0; i < chunksize; i++) {
+                const next = iterator.next();
+                if (next.done) {
+                    break;
+                }
+                res.push(next.value);
+            }
+            if (res.length) {
+                yield res;
+            } else {
+                return;
+            }
+        }
+    }
 }
 
 /**
diff --git a/src/core/config/Categories.json b/src/core/config/Categories.json
index 09ee8d15..2cb9ab0f 100644
--- a/src/core/config/Categories.json
+++ b/src/core/config/Categories.json
@@ -20,6 +20,8 @@
             "From Octal",
             "To Base32",
             "From Base32",
+            "To Base45",
+            "From Base45",
             "To Base58",
             "From Base58",
             "To Base62",
diff --git a/src/core/operations/FromBase45.mjs b/src/core/operations/FromBase45.mjs
new file mode 100644
index 00000000..8e78ed0c
--- /dev/null
+++ b/src/core/operations/FromBase45.mjs
@@ -0,0 +1,78 @@
+/**
+ * @author Thomas Weißschuh [thomas@t-8ch.de]
+ * @copyright Crown Copyright 2021
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation.mjs";
+import OperationError from "../errors/OperationError.mjs";
+import Utils from "../Utils.mjs";
+
+
+/**
+ * From Base45 operation
+ */
+class FromBase45 extends Operation {
+
+    /**
+     * FromBase45 constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "From Base45";
+        this.module = "Default";
+        this.description = "Base45 is a notation for encoding arbitrary byte data using a restricted set of symbols that can be conveniently used by humans and processed by computers. The high number base results in shorter strings than with the decimal or hexadecimal system. Base45 is optimized for usage with QR codes.";
+        this.infoURL = "https://wikipedia.org/wiki/List_of_numeral_systems";
+        this.inputType = "string";
+        this.outputType = "byteArray";
+    }
+
+    /**
+     * @param {string} input
+     * @param {Object[]} args
+     * @returns {byteArray}
+     */
+    run(input, args) {
+        const alphabet = Utils.expandAlphRange("0-9A-Z $%*+-./:").join("");
+        if (!input) return [];
+
+        const res = [];
+
+        for (const triple of Utils.chunked(input, 3)) {
+            triple.reverse();
+            let b = 0;
+            for (const c of triple) {
+                const idx = alphabet.indexOf(c);
+                if (idx === -1) {
+                    throw new OperationError(`Character not in alphabet: '${c}'`);
+                }
+                b *= 45;
+                b += idx;
+            }
+
+            if (b > 65535) {
+                throw new OperationError(`Triplet too large: '${triple.join("")}'`);
+            }
+
+            if (triple.length > 2) {
+                /**
+                 * The last triple may only have 2 bytes so we push the MSB when we got 3 bytes
+                 * Pushing MSB
+                 */
+                res.push(b >> 8);
+            }
+
+            /**
+             * Pushing LSB
+             */
+            res.push(b & 0xff);
+
+        }
+
+        return res;
+    }
+
+}
+
+export default FromBase45;
diff --git a/src/core/operations/ToBase45.mjs b/src/core/operations/ToBase45.mjs
new file mode 100644
index 00000000..019c3dd9
--- /dev/null
+++ b/src/core/operations/ToBase45.mjs
@@ -0,0 +1,74 @@
+/**
+ * @author Thomas Weißschuh [thomas@t-8ch.de]
+ * @copyright Crown Copyright 2021
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation.mjs";
+import Utils from "../Utils.mjs";
+
+/**
+ * To Base45 operation
+ */
+class ToBase45 extends Operation {
+
+    /**
+     * ToBase45 constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "To Base45";
+        this.module = "Default";
+        this.description = "Base45 is a notation for encoding arbitrary byte data using a restricted set of symbols that can be conveniently used by humans and processed by computers. The high number base results in shorter strings than with the decimal or hexadecimal system. Base45 is optimized for usage with QR codes.";
+        this.infoURL = "https://wikipedia.org/wiki/List_of_numeral_systems";
+        this.inputType = "ArrayBuffer";
+        this.outputType = "string";
+        this.args = [
+            {
+                name: "Alphabet",
+                type: "string",
+                value: "0-9A-Za-z"
+            }
+        ];
+    }
+
+    /**
+     * @param {ArrayBuffer} input
+     * @param {Object[]} args
+     * @returns {string}
+     */
+    run(input, args) {
+        const alphabet = Utils.expandAlphRange("0-9A-Z $%*+-./:").join("");
+        input = new Uint8Array(input);
+        if (!input) return "";
+
+        const res = [];
+
+        for (const pair of Utils.chunked(input, 2)) {
+            let b = 0;
+            for (const e of pair) {
+                b *= 256;
+                b += e;
+            }
+
+            let chars = 0;
+            do {
+                res.push(alphabet[b % 45]);
+                chars++;
+                b = Math.floor(b / 45);
+            } while (b > 0);
+
+            if (chars < 2) {
+                res.push("0");
+            }
+        }
+
+
+        return res.join("");
+
+    }
+
+}
+
+export default ToBase45;
diff --git a/tests/operations/index.mjs b/tests/operations/index.mjs
index 9add20b9..75fe6ef9 100644
--- a/tests/operations/index.mjs
+++ b/tests/operations/index.mjs
@@ -20,6 +20,7 @@ import TestRegister from "../lib/TestRegister.mjs";
 import "./tests/BCD.mjs";
 import "./tests/BSON.mjs";
 import "./tests/BaconCipher.mjs";
+import "./tests/Base45.mjs";
 import "./tests/Base58.mjs";
 import "./tests/Base64.mjs";
 import "./tests/Base62.mjs";
diff --git a/tests/operations/tests/Base45.mjs b/tests/operations/tests/Base45.mjs
new file mode 100644
index 00000000..1e821c6d
--- /dev/null
+++ b/tests/operations/tests/Base45.mjs
@@ -0,0 +1,101 @@
+/**
+ * Base45 tests.
+ *
+ * @author Thomas Weißschuh [thomas@t-8ch.de]
+ *
+ * @copyright Crown Copyright 2021
+ * @license Apache-2.0
+ */
+
+import TestRegister from "../../lib/TestRegister.mjs";
+
+TestRegister.addTests([
+    {
+        name: "To Base45: nothing",
+        input: "",
+        expectedOutput: "",
+        recipeConfig: [
+            {
+                op: "To Base45",
+                args: [],
+            },
+        ],
+    },
+    {
+        name: "To Base45: Spec encoding example 1",
+        input: "AB",
+        expectedOutput: "BB8",
+        recipeConfig: [
+            {
+                op: "To Base45",
+                args: [],
+            },
+        ],
+    },
+    {
+        name: "To Base45: Spec encoding example 2",
+        input: "Hello!!",
+        expectedOutput: "%69 VD92EX0",
+        recipeConfig: [
+            {
+                op: "To Base45",
+                args: [],
+            },
+        ],
+    },
+    {
+        name: "To Base45: Spec encoding example 3",
+        input: "base-45",
+        expectedOutput: "UJCLQE7W581",
+        recipeConfig: [
+            {
+                op: "To Base45",
+                args: [],
+            },
+        ],
+    },
+    {
+        name: "From Base45: nothing",
+        input: "",
+        expectedOutput: "",
+        recipeConfig: [
+            {
+                op: "From Base45",
+                args: [],
+            },
+        ],
+    },
+    {
+        name: "From Base45: Spec decoding example 1",
+        input: "QED8WEX0",
+        expectedOutput: "ietf!",
+        recipeConfig: [
+            {
+                op: "From Base45",
+                args: [],
+            },
+        ],
+    },
+    {
+        name: "From Base45: Invalid character",
+        input: "!",
+        expectedOutput: "Character not in alphabet: '!'",
+        recipeConfig: [
+            {
+                op: "From Base45",
+                args: [],
+            },
+        ],
+    },
+    {
+        name: "From Base45: Invalid triplet value",
+        input: "ZZZ",
+        expectedOutput: "Triplet too large: 'ZZZ'",
+        recipeConfig: [
+            {
+                op: "From Base45",
+                args: [],
+            },
+        ],
+    },
+]);