Can I get social security disability benefits for any months before I apply?
The following answer is from: https://faq.ssa.gov/link/portal/34011/34019/Article/3717/Can-I-get-Social-Security-disability-benefits-for-any-months-before-I-apply
We may pay Social Security disability benefits for as many as 12 months before you apply if we find you had disability during that time and you meet all of the other requirements.
If you think you may be eligible to receive disability benefits and would like to apply, you can use our online application.
The following answer is Attorney Walter Hnot’s annotated response to the previous answer.
The 12 months pre-filing benefits are called Retroactive benefits, and are only available for SSDI benefits. SSI claimants are not eligible for retroactive benefits, and can only collect “Backpay” benefits, and “Forward pay” benefits. So, SSDI = Retro+Back+Forward, while SSI = Back+Forward. Remember, Backpay benefits start from the moment you file, while Retroactive benefits start at some prior point where it can be proved that the claimant was in fact disabled.