Stock Screener

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How to Use a Stock Screener to Find Undervalued Stocks

It's not easy finding quality companies to invest in at a fair price.

With thousands of stocks just in the US market alone, thousands more globally, and hundreds of quantitative data points for each stock - there's no way for any individual to manually process all of that data. So how do you narrow down this vast universe of stocks to find companies that fit your investing criteria and strategy?

Fortunately, screening for stocks is a lot easier when you use the best stock screening software. A good stock screener can help you quickly hone in on companies that meet your criteria and suit your investing strategy.

While dozens of stock screeners already exist, WallStreetZen's free stock screener is designed specifically for long-term, fundamentals driven investors who want more control over how they screen for stocks.

We're building what we believe is the best stock screener for part-time investors looking for undervalued companies with strong underlying fundamentals.

What Is a Stock Screener?

Stock screeners (also known as stock scanners, or share screeners) are a database of stocks that let you apply filters to view lists of stocks that meet your investing criteria. Some of the best stock apps let you screen for stocks directly from your brokerage, but advanced investors often prefer more powerful stand-alone stock screening tools.

While the quality of stock screeners can vary greatly, the best stock screeners allow you to screen for stocks based on pretty much any metric or quantitative criteria you care about.

Stock screeners work best when you have a specific idea of the kinds of companies you are looking for e.g. companies with low P/E ratio, high return on equity and low debt, consistent long-term dividends, optimistic stock forecast and predictions, high earnings growth, or technology companies with high growth that are approaching profitability.

Even if you don't have a specific idea of the kinds of companies you are looking for, WallStreetZen's stock screener comes with pre-set filters that match a variety of investing philosophies to get your research started (coming soon).

Stock Screening Is Just the First Step

Stock screeners are a first step in your research, but screeners for stocks can't do all the work for you.

Even the best stock screener apps only let you filter stocks based on the measurable, quantitative factors that affect a stock's long-term value.

For example, our free stock screener app helps you narrow down the universe of stocks based on tangible variables such as market capitalization, revenue, earnings, profit margins, operating income, as well as important financial ratios such as price-to-earnings ratio (P/E ratio), debt-to-equity ratio (D/E), return on equity (ROE), and many more important ratios.

However, qualitative factors like the quality of the company's product, the company's long term business strategy, customer satisfaction levels, pending lawsuits, labor issues, or disruptive technologies that could affect the company's core business aren't something you can easily screen for in a stock screener - it's something you need to learn about as part of your overall research process.

While there are limits to what you can learn about companies just with the numbers, numbers can often give you hints to the qualitative nature of a company's business. Warren Buffett's unique value investing approach is a perfect example of how quantitative analysis can lead to insights about the nature of a company's business.

How Warren Buffett Uses Numbers to Uncover Companies With a Long Term Competitive Advantage

Quantitative analysis can help you understand the fundamental economics of a company's business. As Warren Buffett would say, "accounting is the language of business."

Warren Buffett's strategy has been to invest in companies with a long-term "durable" competitive advantage. He is looking for companies that have a unique "moat" over its competitors which leads to superior economics and returns over the long-term. In other words, Warren Buffett looks for companies with a consistent product that leads to consistent profits.

Because Warren is looking for companies with a long-term advantage, there are certain quantitative rules that he follows. For example, a company with a product that has a long-term durable advantage typically wouldn't have to constantly re-invest into their product. A company like Coca Cola (NYSE: KO), one of Warren's favorite stocks, hasn't changed its core product in over a hundred years. As new colas and flavors of the month come and go, the power of the Coca Cola brand keeps the company on top.

As you might imagine, this means the company doesn't rely on spending millions upon millions in research and development just to keep up with the competition. It also doesn't have to spend billions of dollars retooling its factories every year to manufacture a new model.

As a result, the money tends to pile up on their balance sheet, which also leads to a company that doesn't require much debt to grow its operations.

As you can see, a company's competitive advantage can often be reflected in the numbers if you know what you're looking at. The numbers tell Warren if a company has a mediocre business in a highly competitive industry that will likely generate poor results over the long-run, or whether a company has demonstrated a durable competitive advantage that will spin off consistent profits for years to come.

So based on his investing approach, Warren Buffett can look at a company's financial statements and use quantitative factors to narrow down his universe of stocks.

Among other factors, Warren look for companies that consistently demonstrate:

• High gross margins
• Low debt
• Low research and development costs
• Consistent earnings growth
• High return on equity

All of these are numbers that appear in financial statements, where Warren Buffett mines for companies that have that golden durable competitive advantage.

All of these quantitative factors can be plugged into a stock screener to identify companies that meet Warren's criteria.

But finding companies with durable competitive advantages is just one step in the process, investors also need to determine whether the company is a good buy at the current price.

Because WallStreetZen performs automated Discounted Cash Flow analysis (DCF) on thousands of stocks, our stock screener will allow you to go one step further than most stock screeners, letting you screen for stocks that both meet your investing criteria and are also priced below intrinsic fair value.

After all, Warren's philosophy is to invest in exceptional companies at a fair price, not at any price.

Start Your Research With the Best Stock Screener of 2026

It's worth noting that this quantitative approach to uncovering qualitative advantages works best in industries that are slow to change, and less well in an industry like technology, where a deep understanding of product trends and the ever-changing technology landscape is crucial. However, screening for stocks that have good numbers is always a great first step for uncovering new investing opportunities.

Ultimately, no amount of stock screening can replace a deep understanding of a company's business model and its competitive environment, and gaining that deep understanding requires reading. A lot of reading. Warren Buffett spends 5-6 hours a day reading five newspapers and up to 500 pages of corporate reports.

However, what stock screeners can do is help you narrow down the universe of stocks so that you can focus your limited energy (we can't all be Warren Buffett after all!) into companies that meet your quantitative criteria.

Here at WallStreetZen we're working on building the best free stock screener available, so check back soon. If you have any questions or feedback, feel free to let us know at contact at wallstreetzen.com