Ratio

A ratio simply divides one number by another, such as a share price divided by earnings per share. The result standardises figures so that companies of different sizes can be compared on the same scale. A large company and a small company may have very different total profits, but their profit margins can be compared directly. Ratios are also useful over time: tracking the same ratio across several reporting periods can reveal trends that a single number hides. The key point is that a ratio is only as reliable as the two inputs behind it, so understanding where each number comes from matters as much as the calculation itself.

Investors group ratios into broad categories. Valuation ratios, such as price-to-earnings or price-to-book, relate a company's market price to a financial measure. Profitability ratios, such as net margin or return on equity, measure how efficiently a company generates profit. Leverage ratios, such as debt-to-equity, show how much a company relies on borrowed money. Liquidity ratios, such as the current ratio, indicate whether a company can cover short-term obligations. No single category gives a full picture, and a ratio that looks attractive in one industry may be normal or concerning in another, so comparisons should stay within similar business types. Definitions for individual ratios are collected in our Glossary at /glossary.

Published ratios can differ between data providers because they may use trailing figures, forward estimates, or adjusted earnings. Before acting on a ratio, trace it back to the company's own financial statements and confirm which period and which definition were used. Recalculating a ratio yourself from a company's reported figures is a useful habit. If a ratio looks unusually high or low compared with peers, treat that as a prompt to investigate rather than a conclusion. For broader grounding, our Education hub at /education covers related analysis topics, and if you are ready to apply this research to choosing a broker, the Find my broker workflow at /find-my-broker walks through account verification steps.