If you are wary of on-line calculators, but want to calculate your benefits, or see how working will increase your benefits, there's an Excel spreadsheet attached that will do that for you.
http://www.city-data.com/forum/53930858-post26.html
All you have to enter is your total Social Security Wages for the years (your Social Security Wages are obtained from your W-2 and may be different than your actual total wages for the year).
You can make changes to the wage index as it changes over the years, and make changes to the Primary Insurance Amount and 2nd Bend Point as those change every year, too.
It is accurate only in terms of today's Dollars, because the Wage Index, the Primary Insurance Amount and the 2nd Bend Point change every year.
This link will give you Wage Index Data:
https://www.ssa.gov/oact/cola/AWI.html#Series
This link will give you PIA and Bend Point Data:
https://www.ssa.gov/oact/cola/bendpoints.html
If you're knowledgeable in spreadsheet functions, you can use Statistical Formulas like Trend or Forecast to determine future Wage Index Amounts, or you can eye-ball it or make your best guestimate.
The percent increase in the Wage Index from year-to-year corresponds to the increase in the PIA and 2nd and 3rd Bend Points, so if Wages go up 2.5% then the PIA, 2nd and 3rd Bend Points go up 2.5% as well.
It also assumes you're retiring at full retirement age and not taking benefits earlier, or delaying benefits, which can affect the amount of your monthly benefits.
Neither, actually, but if you insist, then it would be unsubstantiated rumor.
Congress is not going to allow benefits to lapse or be reduced, and any congress-critter that votes against a FICA tax increase or doesn't vote at all will face the wrath of voters, and their choice will become cannon fodder for an opposing candidate, who will win election over the incumbent.
But, as usual, Congress will wait until the very last minute.
Why? Political strategy.
Both Parties know it's a "must pass" Bill. Because it is a "must pass" Bill that means they can cram in all kinds of pork and other amendments to it.
A Real World® example would be the Bill to authorize funding to purchase body armor for troops in Iraq and Afghanistan. My representative, Steve Chabot (R) voted against it 8 times. His opponent used that semi-truth in his political ads, but it back-fired on him, because Chabot then ran political ads saying, yes, he did vote against it 8 times, but he did so to force the removal of the pork and the amendments, you know, like $500 Million for an Exit Ramp to Nowhere, $750 Million for a Bridge to Nowhere, and $2 Billion for Solyndra, and several $100 Million for this corporation and that corporation and tens of $Millions for this pet project and that pet project and this pet program and that pet program.
If Social Security would collapse tomorrow, then what Republicans would do is attach an amendment to the Bill to increase the FICA payroll tax that also authorized spending to build The Wall.
Now, Democrats either have to vote "yes" and approve funding for The Wall or vote "no" and block the FICA tax increase, which makes the Democrats look like the bad guys.
Democrats either have to vote "yes" and approve funding for The Wall, or find some way to politically out-maneuver the Republicans and have the amendment authorizing funding for The Wall removed.
It's just a big game for both Parties.