Faith in online calculators Fidelity/Firecalc?

[Koolau]

I tried a spread sheet once. I wasn't very good at Excel so I ended up with 3 - 10 year serial spread sheets that showed what I knew for certain (how much I had) and then guessed what might happen in the future (rate of growth, spend rate, etc.) It suggested that I was good spending as much as 6% IIRC. Obviously, it was hubris to think I could come up with anything useful.

I was quite glad to have found FIRECalc.

 

[marko]

I tried a spread sheet once. I wasn't very good at Excel so I ended up with 3 - 10 year serial spread sheets that showed what I knew for certain (how much I had) and then guessed what might happen in the future (rate of growth, spend rate, etc.) It suggested that I was good spending as much as 6% IIRC. Obviously, it was hubris to think I could come up with anything useful.

I was quite glad to have found FIRECalc.

Ha! My first spreadsheet just took my portfolio plus growth and divided by 30 years. Found this forum and learned about a nasty little detail named inflation! I was such an idiot! (DW says I still am)

 

[motley]

As an aside, the one thing I worry about is calculators looking back in time many, many decades.

It's not so much "past performance cannot guarantee etc.....", it's that the financial world--and world in general--has changed so much, I can't see how you can use that data.

The stock market today is an entirely different planet than is was in 1940, 1960 or even 1980. How reliable can using such as background? Or maybe I don't understand how it is using data from 1935?

I don't have an alternative and I find tools like Firecalc incredibly useful, but I often wonder how we can rely upon " ... the results of every starting point, since 1871..." as they say.

Just a musing, not a critique.

Funny, I just said more or less the same thing in the "1871" thread under Firecalc support.

 

[Koolau]

Ha! My first spreadsheet just took my portfolio plus growth and divided by 30 years. Found this forum and learned about a nasty little detail named inflation! I was such an idiot! (DW says I still am)

That's why I split my spread sheet into 3. I figured each "stretch" of inflation for each spread sheet. Didn't figure right away how to incorporate into one spread sheet.

 

[marko]

Funny, I just said more or less the same thing in the "1871" thread under Firecalc support.

I saw that. Thought about copying it to the other thread