Finance nerds are having their revenge on Friday as shares of personal finance website NerdWallet (NRDS -4.66%) are soaring in response to a big earnings beat. As of 12:34 p.m. ET, the stock was up by 43.8%.

Heading into the third quarter, analysts had forecast an $0.08 per share loss on $144.4 million in revenue for NerdWallet, but the company beat on both top and bottom lines. Sales for the quarter came in at $152.8 million, and while the company did lose money -- $0.01 per share -- that was a much smaller loss than analysts had expected.  

But NerdWallet still lost money, right?

Right. NerdWallet still did lose $0.01 per share, and this was a worse result than one year ago, when the company reported a $0.01 per share profit -- probably the result they were rooting for given that NerdWallet grew its sales 7% year over year.  

It's worth pointing out, though, that from an operating perspective, things did improve at NerdWallet. As sales grew in Q3, the company held its R&D spending steady, and cut spending in both the sales and marketing (down 2%) and general and administrative categories (down 9%). As a result, whereas NerdWallet was operating at a loss a year ago, and only reported positive net income because of a tax credit, this year it reported a Q3 operating profit ... and only lost money after paying its taxes.

To me, this seems a more sustainable way to earn profits.

Should you buy NerdWallet stock?

It's also worth pointing out that although NerdWallet remains GAAP-unprofitable through Q3 this year, the company is generating significant free cash flow (FCF) from its business -- nearly $23 million so far, versus burning cash through Q3 2022. Run-rate that FCF number out through the end of this year, and NerdWallet could end 2023 with $30.5 million in hard, cash profits, giving the stock a price-to-free-cash-flow ratio of 23.3 -- and an even-cheaper enterprise-value-to-FCF ratio of 20.5, given that NerdWallet carries no debt and has ample cash reserves.

Is that cheap enough to make NerdWallet stock a "buy?"

Perhaps. No analysts have posited a long-term future growth rate for NerdWallet at this time, and management hasn't given clear guidance. Still, "unique user" growth at the company was 22% year over year in Q3, and CEO Tim Chen says it is seeing "record traffic" on the website, "stabilizing performance" in credit card sales, and "positive momentum" in loans.

That all sounds propitious for growth rates to me. Maybe not quite enough to justify a 40% price spike in the absence of a hard prediction on growth rates -- but the stock certainly bears watching.