Your NS&I number
This is the unique ID number we sent you when you registered for our online and phone service. (If you've opened an account online or by phone already, you're automatically registered).
You'll need your NS&I number and password whenever you log in or call us. You'll find it on any letter you've had from us since you've registered.
Your NS&I number is 11 digits long and starts with an 11, 21, 31 or 41. If you can't find your NS&I number, you can get a reminder online:
Get a reminder of your NS&I number
Or you can call us whenever you like: