Skip to content
Toolkit home

Synthetic SSN & TFN Test Pattern Generator

Generate clearly synthetic, non-issuable SSN and TFN test patterns.

US Test Mode

For development, automated QA, and unit testing only. These are non-working, reserved mock values.

Synthetic Mock SSNs
Every value uses an area number the Social Security Administration never assigns — 000, 666, or 900–999.
10
515
  1. 1000-83-2407MOCK · Area 000 is never assigned
  2. 2666-30-4323MOCK · Area 666 is never assigned
  3. 3666-80-6570MOCK · Area 666 is never assigned
  4. 4666-27-0078MOCK · Area 666 is never assigned
  5. 5666-85-6816MOCK · Area 666 is never assigned
  6. 6000-74-3779MOCK · Area 000 is never assigned
  7. 7666-09-3814MOCK · Area 666 is never assigned
  8. 8900-16-0438MOCK · Areas 900–999 are not issued as SSNs
  9. 9000-60-2250MOCK · Area 000 is never assigned
  10. 10957-27-9519MOCK · Areas 900–999 are not issued as SSNs

How the Synthetic SSN & TFN Patterns works

Synthetic SSNs are drawn only from ranges the Social Security Administration never issues, such as area numbers 000, 666 and 900–999, so they cannot belong to a real person.

Australian TFNs use a weighted checksum: each of the nine digits is multiplied by a fixed weight and the total must be divisible by 11. The generator produces numbers that pass the format check for form-validation testing while being labelled as test data.

Formulas used

TFN checksum
Σ(digitᵢ × weightᵢ) mod 11 = 0Weights: 1, 4, 3, 7, 5, 8, 6, 9, 10

How to use the Synthetic SSN & TFN Patterns in 3 steps

  1. Step 1

    Choose US SSN or Australian TFN test mode.

  2. Step 2

    Pick how many values you need and generate them.

  3. Step 3

    Copy the values or export them as CSV for your test fixtures.

Frequently asked questions

Are these real Social Security numbers?

No. They come from ranges that are never issued, so they cannot identify anyone. Use them only in development, QA and demo environments.

How is an Australian TFN validated?

Multiply each digit by the weights 1, 4, 3, 7, 5, 8, 6, 9 and 10, add the products, and check that the sum is divisible by 11.

Related tools