I think they are the same.

also I'd say that in modern language "тому назад" is used far less often than "назад". By no means archaic, the use of "тому назад" has fallen tenfold over the last 100 years. You should know that they are interchangeable in the meaning of "(some time) AGO", and you should understand "тому назад" when you see it or hear it. In practice, however, you would use "назад" yourself, and so would do native speakers most of the time. The catch is, if you are reading books, you aren't ALWAYS exposed to late 20th-early 21th century language.

Тому назад — ago — применяется только относительно времени. Long time ago — Много лет тому назад. Сentury ago — Сто лет назад. _______ назад — back Back to work — Назад, за работу. Look back! — Оглянись назад!

Thanks to both.

1. Назад (where synonym is обратно) - only назад is possible Шаг вперед, два назад. Положи назад, что взял. 2. Назад (where synonym is раньше, прежде) - after words indicated time, period you can use both forms Год (тому) назад. Несколько дней (тому) назад.