VARCHAR to NVARCHAR

So I have an existing table that looks like:

Code:

---

ID          BIGINT
VAL        VARCHAR(128)

---

I am converting this table to something that will be multi language compliant. My question is, I know that NVARCHAR's take double the space of a VARCHAR. Do I actually need to double the length of the VAL field to store the same amount of data or does the DB handle that?

Basically I want to store a 128 character NVARCHAR.. do I need to set my table up like this:

Code:

---

ID          BIGINT
VAL        NVARCHAR(256)

---

or

Code:

---

ID          BIGINT
VAL        NVARCHAR(128)

---

For string datatypes the length is the number of characters that the field can contain - not the number of bytes required to store/use the data.

use NVARCHAR(128)

thank you :)