Settlement amount and SSDI benefits?

Are you talking about worker's comp? Because any other type of settlement has no impact on SSDI.

Worker's comp reduces SSDI because of a federal law which prohibits worker's comp plus social security disability to exceed 80% of the worker's average monthly wage - when that happens SSDI is offset by WC. When a person gets a worker's comp settlement, social security must continue to offset the SSDI for the period of time the settlement represents - since the settlement is in lieu of weekly or monthly worker's comp payments. So Social Security needs to see the settlement papers so that they can figure out how much the offset will be (if the SSDI is already being offset due to WC that offset amount will continue) and when the offset ends.

As for SSI - ANY income reduces SSI (supplemental security income) since SSI is a federal welfare program. It would make a person ineligible for SSI benefits until it is "spent down" to under $2000 if single or $3000 if married. Proof of spend down would be required before SSI benefits could be resumed. Spend down must be on necessities only - not vacations or luxuries or gifts to friends or family.

When you get your settlement papers either take them to your nearest SS office or mail a copy to your nearest office - make sure your social security number is on it. It will take at least 90 days for it to be processed. AT LEAST.

A word of warning - when you get that settlement don't spend it until you know how much of a reduction will be taking place with your SSDI. You just might need that WC settlement money to live on. I once interviewed a man who used his settlement to pay off the mortgage on his house. Unfortunately, the settlement totally offset the SSDI benefit so he had no monthly income for several years (except for the actual cost-of-living increase) - plus he had spent the WC.

If someone has WC offset and the SSDI is zero, they will get cost-of-living increases which means for most SSDI beneficiaries they got a cost-of-living increase of about $2 to $3 a month. It is that amount which a person would receive in this case.

NOTE: WC does not reduce any other type of social security benefit; retirement or survivors - only disability. A person is supposed to report a WC settlement as soon as they receive the papers to avoid being overpaid any further than what they might already be. Eventually the IRS will notify SS of it; for example if received in 2017 social security would receive notification from the IRS late 2018 or 2019. It doesn't leave much of a benefit if the SSDI is reduced because of WC in the first place - and then they have to withhold for an overpayment on top of it.