Social Security beneficiaries will get an 8.7% increase to their benefits in three years' time, the highest increase in 40 years.

The Social Security Administration made the announcement on Thursday. On average, it will result in a benefit increase of more than $150 per month.

The Senior Citizens League estimated last month that the cost of living could be 8.7%.

The 8.7% boost to benefits is the highest increase beneficiaries have seen in the last four decades.

In 1981 the cost-of-living adjustment increased by 11.2%.

As beneficiaries struggle with increasing prices this year, next year's record increase comes as a relief.

Dan Adcock is the director of government relations and policy at the National Committee to Preserve Social Security and Medicare.

Sticking to a plan can help reach retirement goals

People can maintain their standard of living if they have inflation protection.

Beneficiaries will see the cost of living increase in their benefits in January.

Beginning in December, the Social Security Administration will allow you to see how much your check will be.

There are two factors that may affect the size of your benefit check.

The COLAs really are about people treading water; they’re not increases in benefits.

The standard Medicare Part B premium will be lower next year. Payments are usually deducted from Social Security checks.

Mary Johnson, Social Security and Medicare policy analyst at The Senior Citizens League, told CNBC.com that beneficiaries will be able to keep most or all of their increase.

If you have money taken out of your checks for taxes, that might be different.

If you add in your Medicare premium and take your net Social Security benefit, you can calculate how much more money you'll get next year.

Joe Elsasser is the founder and president of Covisum, a provider of Social Security claiming software.

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