diff --git a/index.d.ts b/index.d.ts
index 07096a2f..1342b529 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -16,45 +16,45 @@ export class Buffer extends Uint8Array {
     readIntLE(offset: number, byteLength: number, noAssert?: boolean): number;
     readIntBE(offset: number, byteLength: number, noAssert?: boolean): number;
     readUInt8(offset: number, noAssert?: boolean): number;
-    readUInt16LE(offset: number, noAssert?: boolean): number;
-    readUInt16BE(offset: number, noAssert?: boolean): number;
-    readUInt32LE(offset: number, noAssert?: boolean): number;
-    readUInt32BE(offset: number, noAssert?: boolean): number;
-    readBigUInt64LE(offset: number): BigInt;
-    readBigUInt64BE(offset: number): BigInt;
-    readInt8(offset: number, noAssert?: boolean): number;
-    readInt16LE(offset: number, noAssert?: boolean): number;
-    readInt16BE(offset: number, noAssert?: boolean): number;
-    readInt32LE(offset: number, noAssert?: boolean): number;
-    readInt32BE(offset: number, noAssert?: boolean): number;
-    readBigInt64LE(offset: number): BigInt;
-    readBigInt64BE(offset: number): BigInt;
-    readFloatLE(offset: number, noAssert?: boolean): number;
-    readFloatBE(offset: number, noAssert?: boolean): number;
-    readDoubleLE(offset: number, noAssert?: boolean): number;
-    readDoubleBE(offset: number, noAssert?: boolean): number;
+    readUInt16LE(offset?: number, noAssert?: boolean): number;
+    readUInt16BE(offset?: number, noAssert?: boolean): number;
+    readUInt32LE(offset?: number, noAssert?: boolean): number;
+    readUInt32BE(offset?: number, noAssert?: boolean): number;
+    readBigUInt64LE(offset?: number): BigInt;
+    readBigUInt64BE(offset?: number): BigInt;
+    readInt8(offset?: number, noAssert?: boolean): number;
+    readInt16LE(offset?: number, noAssert?: boolean): number;
+    readInt16BE(offset?: number, noAssert?: boolean): number;
+    readInt32LE(offset?: number, noAssert?: boolean): number;
+    readInt32BE(offset?: number, noAssert?: boolean): number;
+    readBigInt64LE(offset?: number): BigInt;
+    readBigInt64BE(offset?: number): BigInt;
+    readFloatLE(offset?: number, noAssert?: boolean): number;
+    readFloatBE(offset?: number, noAssert?: boolean): number;
+    readDoubleLE(offset?: number, noAssert?: boolean): number;
+    readDoubleBE(offset?: number, noAssert?: boolean): number;
     reverse(): this;
     swap16(): Buffer;
     swap32(): Buffer;
     swap64(): Buffer;
-    writeUInt8(value: number, offset: number, noAssert?: boolean): number;
-    writeUInt16LE(value: number, offset: number, noAssert?: boolean): number;
-    writeUInt16BE(value: number, offset: number, noAssert?: boolean): number;
-    writeUInt32LE(value: number, offset: number, noAssert?: boolean): number;
-    writeUInt32BE(value: number, offset: number, noAssert?: boolean): number;
-    writeBigUInt64LE(value: number, offset: number): BigInt;
-    writeBigUInt64BE(value: number, offset: number): BigInt;
-    writeInt8(value: number, offset: number, noAssert?: boolean): number;
-    writeInt16LE(value: number, offset: number, noAssert?: boolean): number;
-    writeInt16BE(value: number, offset: number, noAssert?: boolean): number;
-    writeInt32LE(value: number, offset: number, noAssert?: boolean): number;
-    writeInt32BE(value: number, offset: number, noAssert?: boolean): number;
-    writeBigInt64LE(value: number, offset: number): BigInt;
-    writeBigInt64BE(value: number, offset: number): BigInt;
-    writeFloatLE(value: number, offset: number, noAssert?: boolean): number;
-    writeFloatBE(value: number, offset: number, noAssert?: boolean): number;
-    writeDoubleLE(value: number, offset: number, noAssert?: boolean): number;
-    writeDoubleBE(value: number, offset: number, noAssert?: boolean): number;
+    writeUInt8(value: number, offset?: number, noAssert?: boolean): number;
+    writeUInt16LE(value: number, offset?: number, noAssert?: boolean): number;
+    writeUInt16BE(value: number, offset?: number, noAssert?: boolean): number;
+    writeUInt32LE(value: number, offset?: number, noAssert?: boolean): number;
+    writeUInt32BE(value: number, offset?: number, noAssert?: boolean): number;
+    writeBigUInt64LE(value: BigInt, offset?: number): number;
+    writeBigUInt64BE(value: BigInt, offset?: number): number;
+    writeInt8(value: number, offset?: number, noAssert?: boolean): number;
+    writeInt16LE(value: number, offset?: number, noAssert?: boolean): number;
+    writeInt16BE(value: number, offset?: number, noAssert?: boolean): number;
+    writeInt32LE(value: number, offset?: number, noAssert?: boolean): number;
+    writeInt32BE(value: number, offset?: number, noAssert?: boolean): number;
+    writeBigInt64LE(value: BigInt, offset?: number): number;
+    writeBigInt64BE(value: BigInt, offset?: number): number;
+    writeFloatLE(value: number, offset?: number, noAssert?: boolean): number;
+    writeFloatBE(value: number, offset?: number, noAssert?: boolean): number;
+    writeDoubleLE(value: number, offset?: number, noAssert?: boolean): number;
+    writeDoubleBE(value: number, offset?: number, noAssert?: boolean): number;
     fill(value: any, offset?: number, end?: number): this;
     indexOf(value: string | number | Buffer, byteOffset?: number, encoding?: string): number;
     lastIndexOf(value: string | number | Buffer, byteOffset?: number, encoding?: string): number;