Savings Rate vs Investment Returns: I Spent Years Optimizing the Wrong One

The spreadsheet that embarrassed me

There's a Tuesday night from my early FIRE years I'd genuinely like back. I sat up past midnight with two browser tabs open, comparing an all-world ETF that charged 0.20% a year against a near-identical one charging 0.12%. My portfolio at the time was about €14,000. That fee gap worked out to roughly eleven euros a year. One lunch. And I was gnawing on it like it was a mortgage decision.

That was the wrong fight. The whole savings rate vs investment returns question is one I spent years arguing from the losing corner, optimizing the exciting number I couldn't control and ignoring the boring one that was quietly doing all the work.

Here's what finally shamed me into stopping. One evening, instead of back-testing another allocation I would never hold, I did something useful by accident. I split my own portfolio into two piles: money I had earned and deposited, and money the market had handed me. I was maybe three years in. The market's pile was thin to the point of insulting. My deposits were the mountain. The returns were a light dusting of snow on top of it. Every evening I'd burned hunting a better fund had been spent polishing the snow while the mountain built itself out of my paychecks.

I'm a software person. I autoinvest into one dull all-world ETF and let it run. I should have seen it sooner. But the returns lever is loud and fun and full of charts, and the savings lever is boring and looks like skipped restaurant meals, so I did what most people do. I fiddled with the loud one.

Let me show you the math that changed my mind, because it's simpler than the fund I almost switched to.

What a savings rate actually is, and how I kept miscounting mine

Your savings rate is the share of your income you actually keep and invest. That's it. Take what you saved and invested in a month, divide by what came in, multiply by a hundred.

Savings rate = (income − spending) / income.

That's how to calculate your savings rate in one line. The trouble isn't the formula, it's how easily you can fool yourself while filling it in, and I managed both of the classic ways. First, the gross-versus-net muddle. You can measure against gross income or take-home pay; gross gives you a lower, more comparable number, net gives you a flattering one. Neither is "correct." Pick one and never quietly switch, because the only thing worse than a low savings rate is a low savings rate you keep re-defining to feel better about. Second, count everything you save. Pension, employer match, the brokerage, the emergency fund top-up. If your employer throws in a match, that belongs in the number, top and bottom.

Now the part almost nobody separates cleanly, which tripped me up for the better part of a year. When you read that "the national saving rate is 3%," that is not the number we're talking about. That figure, 3.0% in the US as of May 2026, is a macroeconomic statistic: personal saving as a slice of all disposable income across an entire country. It is not the percentage of your take-home you're funnelling toward freedom. Don't benchmark your FIRE savings rate against it and feel smug, and don't confuse the two. They share three words and almost nothing else.

Data: FRED (U.S. personal saving rate, PSAVERT).

I show you that national line for one reason: to prove how low typical saving actually runs, and how wildly it swings. It cratered to 1.4% in 2005, exploded to nearly 32% in the lockdown spring of 2020 when nobody could spend a cent, and has drifted back down near 3% since. Whatever the crowd is doing, it is not building a savings rate on purpose. Which, honestly, is most of the opportunity.

Savings rate vs investment returns, in one boring table

Here's the table that reframed everything for me. It comes from Mr. Money Mustache's "shockingly simple math," and a few people have since rebuilt it from scratch and confirmed the numbers hold up. It assumes a 5% real return, a 4% withdrawal rate (so you're "done" at 25 times your annual spending), and a start from zero.

Data: Mr. Money Mustache, "The Shockingly Simple Math Behind Early Retirement."

Read it as years of work left before you could stop, based on nothing but your savings rate.

Save 10% of your take-home, and you're looking at roughly 51 years. Bump it to 25%, and it's 32. Half your income, and you're free in about 17. Three quarters, and it's around 7 years, start to finish.

Look at what did the moving there. Not a fund. Not a market forecast. Not a factor tilt. Just the fraction you keep.

And it works on both ends at once, which is the bit that took me embarrassingly long to feel in my gut. Every extra point you save is a point more going in, and a point less you spend, which lowers the pile you need in the first place. Spend less and the finish line walks toward you while you're also running at it faster. That 25x target the 4% rule leans on shrinks the moment your spending shrinks. I poked at whether the 4% number even still holds in Safe Withdrawal Rate 2026, because it's the other half of this same equation.

There's a mercy hidden in the table, too. The biggest wins sit down at the bottom, where people feel most stuck. Going from a 5% to a 10% savings rate hacks about 15 years off the clock. Going from 90% to 95%, when you're already a machine, buys you about one. So if you're saving almost nothing right now, you have the most to gain from your next single point, not the least.

Most money advice aimed at people in the first decade of building wealth has this exactly backwards. It obsesses over the return, the fund, the allocation, the levers that barely move a small pot, and treats the savings rate as a bit of throat-clearing before the fun stock-picking starts. It's tuning the engine before there's any fuel in the tank.

In the early years, you basically are the returns

Let me make the "small pot" thing concrete, because it's the heart of the whole argument.

Model a simple saver: €500 a month, a 7% return, starting from nothing. Watch where the balance comes from as the years pass.

Data: modeled illustration (EUR500/month, 7% nominal); directional anchor money.ca.

In year one, about 97% of your balance is just money you put there. The market chipped in 3%. Three. After five years you've got around €36,000, and roughly €30,000 of it is still your own deposits. The returns you'd stay up late optimizing are, at this stage, a rounding error wearing a cape.

So run the comparison that actually matters early on. Say you could either save one extra point of a modest income, call it another €100 a month, or magically earn a full extra percentage point of return on a €15,000 pot. The extra saving puts €1,200 more to work this year. The extra return earns you €150. It isn't close. This is the old "what matters more, saving or investing" argument, and while your pile is small it barely qualifies as an argument. A couple of extra savings-rate points out-punch a whole point of return every time, and the pile stays small for years.

Morgan Housel put the human version of this better than I can. He points out there are professional investors grinding eighty-hour weeks to add a tenth of a percentage point to their returns while ignoring two or three whole points of lifestyle bloat sitting right there in their own budget, cuttable with far less effort. I was a tiny amateur version of that guy. Tenth-of-a-percent hunter, bloat ignorer.

This is the same reason the first hundred grand feels like dragging a cart uphill: your own deposits are nearly the entire story, and I wrote a whole piece on surviving that slog in why the first $100k is the hardest. Same physics, different milestone.

When returns finally start to win

Now the honest part, because if I stopped here I'd be selling you a religion instead of a tool.

So does savings rate matter more than returns? For the first decade of building wealth, yes, and it isn't close. But "forever" is where I have to stop nodding along, because the savings rate does not win the whole race. It wins the first leg. There's a crossover, it's real, and it shows up sooner than the savings-rate diehards like to admit. In that same €500-a-month model, somewhere around year 11 the market's annual gain quietly overtakes your annual contribution. Your money out-earns your paycheck's deposit for the first time. Push on to about year 20 and total growth passes the total of everything you ever put in. From there, compounding is the engine and your contributions are the rounding error, the exact mirror image of where you started.

Past that point, returns matter enormously, and pretending otherwise gets dangerous. A single percentage point of return, compounded on a big balance, is not pocket change anymore. Motley Fool ran the numbers this July: $10,000 a year for 30 years at 10% versus 9% leaves you about $362,000 apart at the finish. Near and after retirement it gets sharper still, because the order of your returns starts to matter. A bad sequence in the first decade of drawdown can drive something like three-quarters of your final outcome, and no savings rate rescues you once you've stopped earning.

There's also the exception that keeps me honest about my own smugness. I mocked my 0.20%-versus-0.12% evening, and I stand by that; that gap was noise. But a genuinely expensive fund is a different animal. Paying 1.00% a year instead of 0.10% can quietly surrender something like 22% of your ending wealth over 30 years. That is not noise. Fees are the one "return" lever you fully control, so if you're stuck in a 1%-plus fund, fixing it is real, permanent, savings-rate-grade leverage. Chasing three basis points is a hobby. Escaping a 1.2% fund is a decision.

And the biggest honesty check of all: "just save more" is not a lever everyone has. Plenty of people are saving nothing because the rent already ate it. Roughly three in four workers report they can't stretch much past basic living costs. Telling someone on a 25th-percentile wage to lift their savings rate isn't math, it's a scold. For them the real lever is income, not frugality, and that's a different article. Which lever is even yours to pull depends on where you're standing, which is exactly why I map it to stages in the five stages of financial freedom. Nick Maggiulli compressed the whole thing into five words: save when you're poor, invest when you're rich. Early you, small pot, save. Later you, big pot, optimize. I just had the order flipped for years.

What I changed, and the evenings I'm not getting back

So I stopped. Not gracefully, but I stopped.

I automated a higher savings rate first, before anything went near a chart. The transfer to investments now leaves on payday, ahead of me having any opinions about it. Then I picked one broad, cheap, all-world ETF, put it on autoinvest, and quit auditing it. No more allocation back-tests I'd screenshot and never act on. No more waiting for a "dip" to deploy the monthly money, a habit that mostly meant cash sat idle sulking while the market drifted up without me.

The energy I used to pour into shaving basis points I moved to the two things that actually respond: saving a bigger slice, and earning more so there's a bigger slice to save. One of those redirections has done more for my numbers than every fund comparison I ever ran, put together.

I won't pretend the wasted evenings don't sting a little. There were a lot of them. The one decent thing about learning a lesson late is that you at least get to stop paying for it.

How to raise your savings rate without hating your life

If the savings rate is the lever, the obvious question is how to move it without turning your life into penance. A few things that actually worked for us, none of them about your morning coffee.

Go after the big three first: housing, transport, food. These are the boulders. Your rent or mortgage, the car you chose, the weekly grocery-and-takeaway habit; get those right once and the savings show up every single month with no further willpower required. The whole "cut the latte and retire a millionaire" genre gets the scale wrong. I actually ran that fight to the ground in the latte factor, tested, and the coffee loses to the mortgage every time. The same logic sits underneath treating minimalism as a FIRE accelerant: it isn't deprivation, it's refusing to pay for a bigger life than you want.

Then automate the raise before lifestyle creep gets to it. When your income goes up, decide in advance that a fixed share of the increase goes straight to investing, ideally before it ever touches your spending account. A raise you never see is a raise you never inflate into. This is the quiet move that separates two people who out-earn each other yet end up at the same balance: one banked the raises, one absorbed them.

None of this is a personality transplant. A savings rate for FIRE doesn't get built by suffering harder. You set the big things low once, then let the automation carry the boring rest.

Savings rate vs investment returns, and the one number I watch now

Here's the shift that stuck. I stopped opening my portfolio to stare at daily prices or second-guess the fund, and I started tracking two numbers a month instead: my net worth, and my savings rate. And yes, this is the part where I admit I build a tool for exactly this, so salt to taste. The principle holds whether you use my thing, a notebook, or a spreadsheet with one embarrassing formula in it.

Net worth tells you where you are. The savings rate tells you whether you're actually pulling the lever you control, this month, in a way a return number never can. A good market month can flatter a lazy savings rate into looking fine. Watching the savings rate strips that flattery off. It's the honest mirror.

That's the real resolution to the whole savings rate vs investment returns argument, at least for anyone still in the building years. They're not two equal contestants. They're a relay. The savings rate runs the first, long, decisive leg. Returns take the baton later and sprint the rest of the way home. My mistake was standing at the finish line cheering for the sprinter while the first runner was still out on the track, alone, quietly doing the actual distance.

I still autoinvest into the same boring ETF. I still don't touch it. The only thing that changed is that the number I check now is the one I can actually move, and most months I can move it a little. That turned out to be the quiet freedom the loud version of investing never sold me. Not a better return. Just a bigger slice, saved on purpose, until the boring number buys the thing the exciting one only ever promised.