Comparing Social Security Calculators

Last updated: August 12, 2023

One of the many stunning mineral displays at the Perot Museum

After building a tool to compute social security income, I really wanted to check it against other social security income calculators out there before diving into the analysis I want to do

Validation is critical! I really want to make sure the results I get are trustworthy.

So I found a bunch of online calculators and got busy doing comparisons.

Scenarios Used

To compare each calculator, I needed to use consistent scenarios. It’s very important to compare apples-to-apples if at all possible. Just like when shopping for insurance!

Fortunately there are really just a few inputs:

  1. Earnings history
  2. Birth date
  3. Year you’d like to start social security

I built my social security income tool using the Case A and Case B examples laid out by the SSA, because I could check my values at each step – super handy. 

That same handiness made these the ideal examples to use in all the different calculators.

And if the calculator got the base scenarios correct, I also explored variations on those cases. Though I tried to focus on current and future values for those variations, vs past values – that’s what’s important to me and the analysis I want to do, and for past values I’m not sure what different calculators will do in terms of present vs past value of dollar, etc. I assume all future values will be provided in present day dollars.

The only additional info I added to Case A and B was choosing the day of year for birth date. The SSA only specifies birth years of 1961 and 1957. 

I chose January 2, 1961 for Case A, and January 2, 1957 for Case B, to keep the comparisons as direct as possible, and avoid the strange January 1 rule Calculator

The official online calculator from seemed like the best first option to try – hopefully the folks actually sending you social security checks have the correct amount in their calculator!

I considered their downloadable offline “Detailed Calculator”, but it was updated less recently than the online calculator, and they also say “The Detailed Calculator has many features which are not necessary for normal retirement benefit estimates. If you do not require these features, you should try using the Online Calculator first, because it is much easier to use.” A very honest assessment from the government, nice! 

Unfortunately the formatting for entering the earnings each year is a bit weird and tedious (lots of manual entry, which presents lots of risk for mistakes), but it’s manageable. 

In the end, it got the correct answer for Case A and B, as expected. Excellent.

I then tried some variations, such as adding and subtracting $100K to different years, looking at different retirement dates, and everything matched what I generated with my tool. Excellent.

Open Social Security Calculator

A while back I was reading the latest post from Karsten at EarlyRetirementNow, and he mentioned a tool called So I decided that would be a good next tool to try.

However, computing your retirement insurance benefits (RIB) (your standard social security income) is not the primary goal of Instead, they attempt to provide insight on when the optimal time to start RIB is based on actuarial probabilities of death each year – fun!

So instead of asking what your earnings history is, it directly asks for your Primary Insurance Amount (PIA). Easy enough though, we have that for Case A and B.

For case A, I plugged in Single, Male, born Jan 2, 1961, with a PIA = $2,263. (It’s actually $2,263.30 for case A, as it’s truncated down to the lower dime, but for some reason doesn’t allow sub-dollar amounts – weird.)

Finally, I plugged in a real discount rate of 7%, assuming the money is invested in a low-cost, broad-based index fund that achieves an ROI of 7% (after inflation) annually. The 1% default used is crazy low / excessively conservative to me.

With those inputs, it recommends starting RIB in May 2023 at 62 and 4 months – ASAP essentially. That should maximize the total expected lifetime amount of money you’ll derive from social security (including investment returns I assume). 

Then the table at the bottom provides the annual RIB value corresponding to a retirement age of 62 years and 4 months: $19,462/year = $1621/month. (Shown after the current year, since you’d start RIB part way through the year.) 

That matches the $1622 I computed with my tool (within a dollar at least, which might be because of how I had to strip the $0.30 from the PIA).

So looks good, as expected with the recommendation from Karsten. Calculator

Now when I was using the tool, I saw a recommendation at the top for a calculator called Especially for computing your PIA if you don’t have it already. So, that was the next tool I tried.

And it’s a great tool!


First off, providing the earnings history is dramatically easier than the official online calculator from Instead of manually copying and pasting in each year’s earnings, you can just paste in a table of earnings values and it automatically and instantly parses it correctly. Fantastic.

The tool then proceeds to dazzle you with lots of well made visuals and tables showing a variety of useful things:


Beyond being super visually attractive and thorough, also gives the same answers as me! Woohoo! 

For both Case A and B, my AIME, PIA, and RIB values matched theirs. Then I looked at a variety of other retirement ages, and our answers always matched perfectly. Excellent!

Other Calculators

So after trying the above calculators, I decided to find some others via googling, to see if I could find some other good options that further validate the answers I’m getting. 

Unfortunately, nearly all of them had the same issue: they don’t allow you to input your actual earnings history. 

Instead you are usually asked to input some kind of “average” salary, and they guestimate your RIB based on that. As a result, I found that the estimated RIB value was not very accurate for Case A or B scenarios.

The challenge is that I have no idea what to put for this salary value: the most recent salaries for Cases A and B? The average of all the previous years? The average of all the inflation adjusted earnings? None of these gave the correct value either.

Below is a list of the calculators I tried that employ this guestimation based on a single salary value:

Of these calculators, NerdWallet’s seems to give the most accurate answer, but that might have just been luck. CreditKarma’s tool also seems somewhat close, but concerningly they don’t even truncate to the dollar amount for the final result, which makes me wonder how solid their grasp is of the underlying math. at least explains what they’re assuming with the single salary input: “Annual Income: We assume that your income in the future increases by the rate if [sic] inflation and your income in the past is discounted by the same inflation rate”. While that’s not the worst assumption, I doubt that’s going to correspond to almost anyone’s earning history.

In general, these calculators are just not getting enough info to give you a realistic amount for RIB. Thus unless the calculator lets you input your entire earnings history, don’t expect a realistic answer. 

I also ran across some other calculators that weren’t what I thought initially:

  • is not computing your RIB, but rather the best age to take RIB, a la However, the only inputs are birth year, life expectancy, investment ROI, and COLA. Weird.
  •’s calculator is actually computing taxable RIB from the nominal RIB, not the nominal RIB itself
  • Fidelity’s calculator of course requires you create an account and log in. Of course they would have a super user unfriendly option that collects and saves as much data about you as possible. Bleh, not a fan of that company at all. 

Finally, I came across a site that seemed really promising initially:

Their RIB calculator allows you to input your entire earnings history, even if it’s a painful copy and paste each value operation a la SSA’s tool, vs the slick entire table paste that offers. But still, it’s really good that it lets you do that. 

Unfortunately, it also never gave me the correct answer either. Booo. No idea why. I think I put everything in correctly, but maybe I missed something somehow. If you get the correct answer for Case A or B, let me know – I’d love to know what I’m doing wrong if so.

Conclusions and Future Work

So in the end, I only found three calculators that I consider respectable and accurate: the official online calculator from, the calculator (even if it’s not focused on computing RIB), and the calculator. 

And unsurprisingly I found the calculator via, and I found the calculator via Chain of trust/reliability!

Regarding future work regarding social security income, I laid that out last week fortunately.

Other Tools To Consider?

Do you know and like/use any other social security calculators/tools? If so, please let me know and I’ll check them out.

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