If Excel Had a One-Night Stand With cFIREsim

[Hey guys! If you love numbers and forecasting and poking around new financial calculators, you’re going to enjoy this review of OnTrajectory today :) It comes from Gwen of FieryMillennials.com and should give you something exciting to do over the weekend! Haha… Hope it helps!]


Hi my name is Gwen, and I have a confession.

I love spreadsheets.

Not like, oh yeah occasionally I play around in Excel making spreadsheets. No no.


Chances are high you feel the same way. Many drawn to the FIRE life want to optimize their lives to the fullest, and one of the best ways to do so is through spreadsheets.

Months of income neatly listed in columns. Years of expenses documented in different tabs. Beautiful graphs made from forecasting the FV formula.

I can’t. Get. Enough.

Eventually, though, if you’re anything like me, you run out of variables to change. The joy starts to fade from putzing around in Excel, and you need something more to keep up the high…

Enter, OnTrajectory.

ontrajectory logo

I’m pretty sure this beautiful piece of software is a love child from Excel having a one-night stand with the cFIREsim calculator.

OnTrajectory (or OT) bills themselves as “A Financial Planner and Analyzer – All in one easy-to-use graphically interactive program.” They’re not wrong. It’s beautiful.

You start off entering in some details about you: age, total savings, annual income, and how much income you save monthly. You can skip these questions and enter them manually if you want a more granular control over where that information goes.

After it processes the information, you’re taken to the main screen where you have a number of options.

Let’s start with income:

ontrajectory income screen
[click to enlarge]
The thing I love most about OT is the flexibility to include multiple streams of income that last as long as you want.

  • Day job income until you’re 34? Done.
  • Great Aunt Ethel passes away when you’re 50? Put that chunk of change in there.
  • Lucky enough to get a pension that starts at age 65? You guessed it: that can go in there as well!

Moving on to expenses:

ontrajectory expenses screen
[click to enlarge]
Much the same story as income, except these are all the things you’re spending money on.

  • Only paying for college for 2 years for the kiddo? You can include that.
  • Finish paying off the house at age 45? You get the picture.

I also like that you can go super granular and include your actual budget for expenses. It’s for those that really want to go deep into their budget and estimate how changing things like not spending money on work clothes and spending more money on vacations and tequila affects their timeline.

(I may or may not be one of those people.)

After expenses comes the really fun part: Accounts and Taxes

(Is that the first time anyone has ever said taxes are fun?)

ontrajectory accounts taxes-screen
[click to enlarge]
This is the section where you get to add in all of your existing accounts. If you’re like me, this could take awhile. It’s worth it, I promise.

Notice how in the picture above I have a 401k in there? Well, if you look closer at the numbers that I totally made up out of the blue, you’ll notice how it has two sections. The first section is the years I’m going to contribute money to it while I’m still working. The second part is the growth stage, where I don’t touch my beautiful little nest egg and let it grow untouched for 29 years.

As with all the other sections, you can change the date ranges and amounts contributed to see how it changes your trajectory. One really fun thing to do is to look at what your projected end number is if you stop contributing to you 401(k) this year. I bet the number is higher than you would think it would be! I wouldn’t recommend, however, seeing what your number would be if you worked for 35 years and contributed the max. Let’s just say I’d be worth well over 7 figures if I decided to sacrifice the best part of my life to ‘The Man’.

The next tab is “goals”

I’m going to be completely honest here and let you know I haven’t fiddled with this section too much. Simply because I’m a Type A person and I don’t like setting goals that are so dependent on something as flaky as the US Stock Market.

There are a number of goals you can set, though, like Trajectory reaches $ on this Date _____,  Projected Progress reaches $ on this Date ______, and Trajectory reaches $ on _____ at this cumulative RATE _____.

The last and final tab is simply a list of all the progress check-ins you’ve done so far.

Everything combines to make a chart that looks something like this:

ontrajectory end balance graph
[click to enlarge]
As you can see, this very simple example would have me living a life full of comfort and luxury until the end of my days. Yay!

I know this because not only does the graph end on a record high, there is also a handy dandy notification that says so. Not in those exact words though, sadly.

The notification area comes with a variety of different messages, from successful trajectory to early withdrawal penalties to projected shortfall warnings. Here are what some of them look like:

ontrajectory future notifications

At the risk of babbling on and on about this awesome website (seriously I could talk about it all day. I feel like I’ve barely scratched the surface!) I will end with a quick summary.

Pros of using OnTrajectory

  • Gives you robust projection capabilities that Excel can’t provide
  • Can get way down into the details
  • It’s very well documented
  • It looks great!
  • Their support responds promptly (now with a dedicated subreddit!)

Cons of using OnTrajectory

  • The free version only lets you put in a few accounts (which is fine to poke around, but to truly get a good idea you need to add all your different accounts which requires upgrading to the “PowerPlan” at $5.00/mo)
  • Takes a while to set up the first time


OnTrajectory really lets you dig into the nitty gritty details if you’re a numbers person. I’ve been using them for over a year now and I love it. I feel far more confident with my plans now that I can see the definite impact of working a few more years or not fully maxing out my 401(k).

Highly recommend checking them out: OnTrajectory.com

UPDATE: Two more options have since been implemented:

  • Full consolidated PDF Reports of one’s overall Trajectory, as well as graphs / output data for all individual Income / Expense / Account items.
  • Ability to create and share “Scenarios” with others (for example, if you wanted to demonstrate tax-handling techniques or just various assumptions about growth or contributions, and how it could be comparatively handled to reach a goal)


Gwen is the founder of fierymillennials.com, a blog about achieving financial independence from a millennial’s point of view. She’s on Twitter [@fierymillennial] and also has Instagram and Facebook.

FYI: This post includes affiliate links to OnTrajectory, but of course we only blog about products we love and use here regardless of compensation. If we think it’ll help you we’ll share it!

[Awesome pic up top of the founder of OnTrajectory, Tyson Koska ;)]

(Visited 115 times, 1 visits today)

Get blog posts automatically emailed to you!


  1. Mustard Seed Money September 29, 2017 at 6:45 AM

    This is awesome. I love playing around with spreadsheets so I will definitely have to sign up and see how i like it. Thanks for sharing!!!!

  2. Cubert September 29, 2017 at 6:53 AM

    Oooohhh… it’s like catnip for clones! (or cocaine for early-retirement spreadsheet wonks?)

    Very cool, Gwen. I love my Excel though (the only thing that’s “Microsoft” I can say -that- about.) So much that I even figured out how to run simulations with it. But for folks who are not as comfortable with .xls, I think OnTrajectory might be a good gateway drug. Errr, retirement planner. Yeah, that’s what I meant.

    1. Gwen @ Fiery Millennials September 29, 2017 at 8:56 AM

      Is that why I keep having to **sniff** all the time?? hahaha

      Excel is awesome if you know how to use it, but not everyone loves to dive in deep like us. For everyone else, there’s OnTrajectory. Hmmm that’s catchy. Sounds like a good slogan! ;)

  3. sam September 29, 2017 at 6:54 AM

    hey gwen..! i love numbers & i love your review, cfiresim calculator its really nice. thanks for sharing !

  4. Mrs. Adventure Rich September 29, 2017 at 7:51 AM

    So cool, thank you for sharing your review, Gwen! I’ll have to check this one out (I’m always looking for a fun calculator to play around with…!).

    1. Gwen @ Fiery Millennials September 29, 2017 at 8:57 AM

      You’re welcome, Mrs. Adventure Rich! Have fun and let me know what you think!

  5. Ms. Frugal Asian Finance September 29, 2017 at 7:51 AM

    Great title! Excel is such a great tool. It can go from basic calculations to complex formulas that can help simplify our complicated problems.

    I’m not in love with Excel per se, but after I started blogging, I’ve been obsessed with Google Analytics. I can just stare at GA without blinking to process all the great data it offers. Why do I love Google even more? Google search and Google Analytics!!

    1. Gwen @ Fiery Millennials September 29, 2017 at 8:58 AM

      Oh man…. GA and site stats are a whole nother topic I could talk about all day. It’s so addicting!

  6. SC September 29, 2017 at 7:56 AM

    They are pretty quick to respond to bugs and feature requests. One bug I found was fixed basically over night. And then my suggestion of drawing down from non tax advantaged accounts first was implemented in about a week.

    1. Gwen @ Fiery Millennials September 29, 2017 at 8:59 AM

      Yeah their support is amazing. Very responsive! Thanks for reading SC!

  7. Leo T. Ly September 29, 2017 at 8:00 AM

    I have been maintaining my spreadsheet for about ten years now and it’s just rinse and repeat every quarter when I do my net worth calculation.

    Yes, the joy of creating new formula and graphs definitely diminished over time. However, the joy of seeing your net worth grow exponentially is still there.

    As a parent of two young kids, it’s difficult to spend the same amount of time that I used to when I had no kids. This tool seems interesting and maybe it’d save me some time in the future once I migrate my numbers to OT.

    1. J. Money October 3, 2017 at 2:27 PM

      I second the kids situation :)

  8. Mr. Freaky Frugal September 29, 2017 at 8:06 AM

    Gwen – Thanks for the tutorial!

    I love cFIRESim and FireCalc and use both all the time.

    I have looked at OnTrajectory and it just felt too complicated for me. It may have to do with the fact that I’m already FIREd so I’m really looking for how much we’re under-spending. This is easy to do with cFIRESim and FireCalc because you can configure both of them to tell you how much you can afford to spend and still have a theoretical 100% success rate. Can you do that with OnTrajectory?

    1. tykonderoga September 29, 2017 at 5:49 PM

      Yes, if you “over spend” you can run the “shortfall” warning to figure out how much more on average you need to save.

    2. Gwen @ Fiery Millennials October 1, 2017 at 4:26 PM

      I’m not entirely sure since I haven’t tried to do that with OT. I can play around in it and let you know though!

  9. Lance @ My Strategic Dollar September 29, 2017 at 8:28 AM

    Thanks for sharing! Excited to take a look at this and play around with some scenarios!

  10. Amy @ Life Zemplified September 29, 2017 at 8:37 AM

    You had me until the $5/month…(dang am I really that cheap?!) Sounds like a great tool though, thanks for sharing!

    1. Gwen @ Fiery Millennials October 1, 2017 at 4:28 PM

      Yeah $5/mo is something to consider, but I’d say it’s worth it!

  11. Dave @ Married with Money September 29, 2017 at 8:53 AM

    This seems super cool. I may have to play around with the free version for a bit when I have time (LOL which is never, damn moving…) and see how I like it.

    I’ve been slowly building something similar out for my own purposes as well. :)

    1. Gwen @ Fiery Millennials October 1, 2017 at 4:29 PM

      Ah the ol “when I have time”…. I’ve found myself to be short on that too lately!

      I’d be interested to see what you’ve got so far!

  12. Miss Mazuma September 30, 2017 at 11:16 AM

    Ohhhhhh – I am intrigued. I love me a good spreadsheet las much as the next (nerdy) person but I haven’t found the right FIRE calculator yet. So many variables!! I hope this will be “the one”!! :)

    1. Gwen @ Fiery Millennials October 1, 2017 at 4:29 PM

      Just as long as you tell everyone I was the one to introduce you! ;)

  13. Balanced Dividends Mike September 30, 2017 at 7:26 PM

    It does look quite interesting – thanks for sharing!

    I don’t think $5 is too much for a powerful, helpful tool. But what are your thoughts on this tool vs. Personal Capital or similar apps / tools?

    I definitely enjoy numbers and tracking, but the time to setup and for maintenance looks intensive if you’re to utilize all the various functions.

    1. Gwen @ Fiery Millennials October 1, 2017 at 4:32 PM

      Personal Capital is good for seeing all of my investments. I like that they tell me what % of the market I’m holding and the fee analyzer is awesome.

      OT is strictly for projecting out the FIRE path. I can play around with different hypothetical scenarios and see what makes a difference. I can’t really do that with Mint/PC/YNAB.

  14. Billy B @ Wealth Well Done October 1, 2017 at 8:08 PM

    Cool, review that opens my mind up to the potential and possibilities of spreadsheets. Unfortunately, I don’t have any natural skills when it comes to spreadsheets. That probably stems from too many years working on a typewriter that was engineered long before interactive spreadsheets even existed. Will have to give them a try and see how they go.

    1. J. Money October 3, 2017 at 2:29 PM

      I swear – one of these days I’m totally typewriting up one of my blog posts and scanning it here, haha… Wouldn’t that be so cool/nerdy? :)

  15. Chris @ Keep Thrifty October 2, 2017 at 9:57 PM

    As a recovering spreadsheet addict, I’m afraid to dive in here. I know once I get in I might never get out again.

    Ahhh screw it! *clicks to site*

    1. J. Money October 3, 2017 at 2:29 PM

      Haha.. DO ITTT!!!!!!!!!

  16. ZJ Thorne October 8, 2017 at 11:45 AM

    It’s awesome that they let you see the impacts of rental income and leaving your 401K alone for years. Neat tool!

  17. Jason@WinningPersonalFinance October 17, 2017 at 8:20 AM

    This looks awesome! I will definitely check it out. I’m also a spreadsheet addict and am sad that I can’t post all my blog content in spreadsheet form. For some reason, people want words.

    1. J. Money October 17, 2017 at 9:25 AM

      okay, now THAT is funny :)

  18. Easy Living 101 December 21, 2017 at 2:56 AM

    This calculator is completely useless.