Market Capitalization Calculator
Calculates a company's total market capitalization by multiplying its current share price by the number of shares outstanding. Use it to classify a company as small-, mid-, or large-cap and compare it to peers.
About this calculator
Market capitalization represents the total market value of a company's outstanding equity shares. The formula is: Market Cap = Share Price × Outstanding Shares. It is the most widely used shorthand for a company's size in financial markets. Companies are commonly grouped into tiers: micro-cap (under $300M), small-cap ($300M–$2B), mid-cap ($2B–$10B), large-cap ($10B–$200B), and mega-cap (over $200B). Market cap differs from enterprise value, which also accounts for debt and cash. Because share price fluctuates continuously, market cap changes throughout every trading day, making it a real-time snapshot of what the public market believes a company is worth.
How to use
Suppose a technology company has 500 million shares outstanding and its stock currently trades at $42.00 per share. Enter $42.00 as the Share Price and 500,000,000 as Outstanding Shares. The calculator computes: Market Cap = $42.00 × 500,000,000 = $21,000,000,000 (or $21 billion). At $21 billion, this company falls firmly in the large-cap category. You can now compare this figure against competitors or index inclusion criteria to put the valuation in context.
Frequently asked questions
What is the difference between market cap and enterprise value?
Market capitalization measures only the equity value of a company — share price times shares outstanding. Enterprise value (EV) goes further by adding total debt and subtracting cash and equivalents, giving a more complete picture of what it would cost to acquire the entire business. EV is preferred for comparing companies with very different capital structures, while market cap is useful for quick size comparisons and index classification.
How does share buybacks affect a company's market capitalization?
Share buybacks reduce the number of outstanding shares. If the share price stays constant, fewer shares mean a lower market cap. In practice, buybacks often signal management confidence and can push the share price higher, which may keep market cap stable or increase it. The net effect on market cap depends on whether the price appreciation outweighs the reduction in share count.
Why do index funds use market cap weighting to determine position sizes?
Market-cap weighting means each company's representation in the index is proportional to its market value relative to all other companies in the index. This approach is favored because it reflects the collective judgment of all investors about relative company values and requires minimal rebalancing since prices adjust automatically. It also ensures larger, more liquid companies receive greater weight, reducing trading costs for fund managers who track the index.