# What is my market share?

Computes market share: your sales as a percent of the total sales in your market, in dollars or units, with the relative market share against your largest competitor.

- Page: https://www.acalculator.org/finance/market-share-calculator
- JSON spec: https://www.acalculator.org/finance/market-share-calculator.json
- Version: b4038c169d0c

## Default answer

Example with the default inputs (Your sales 1,000,000, Total market sales 20,000,000, Largest competitor’s sales 1,500,000): Sales of 1,000,000 out of total market sales of 20,000,000 are a market share of 5%.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| sales | Your sales | Your sales in the period, in dollars or in units. |
| market | Total market sales | The sales of every company in the market in the same period, yours included, in the same measure. |
| leader | Largest competitor’s sales | The sales of your largest competitor (the next largest, if you lead), for the relative market share. Leave it empty to skip it. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| share | Market share | Your sales ÷ total market sales × 100. |
| others | Competitors’ share | (Total market sales − your sales) ÷ total market sales × 100. |
| leaderShare | Largest competitor’s share | Their sales ÷ total market sales × 100. |
| relative | Relative market share | Your sales ÷ your largest competitor’s sales × 100. |

## Method

Market share = your sales ÷ total market sales × 100; relative market share = your sales ÷ largest competitor’s sales × 100, which equals your share ÷ their share × 100.

## Assumptions

- Your sales, the market total and the competitor’s sales use the same measure (dollars or units) and the same period.
- The total market sales include your own sales.
- Arithmetic is exact on the typed decimals; the shares show to 2 decimals.

## Worked examples

1. sales = 1,000,000, market = 20,000,000, leader = 1,500,000 gives share = 5%, others = 95%, leaderShare = 7.5%, relative = 66.666667%. Source: OpenStax, Principles of Marketing, 2.4 Marketing Plan Progress Using Metrics (market share in a category = the company’s sales ÷ the total sales in the category; relative market share = your share ÷ your leading competitor’s share). https://openstax.org/books/principles-marketing/pages/2-4-marketing-plan-progress-using-metrics: $1 million a year is a 5% share.
2. sales = 4,500, market = 30,000 gives share = 15%, others = 85%. Source: OpenStax, Principles of Marketing, 2.4 Marketing Plan Progress Using Metrics (market share in a category = the company’s sales ÷ the total sales in the category; relative market share = your share ÷ your leading competitor’s share). https://openstax.org/books/principles-marketing/pages/2-4-marketing-plan-progress-using-metrics.
3. sales = 6,000,000, market = 20,000,000, leader = 4,000,000 gives share = 30%, leaderShare = 20%, relative = 150%. Source: OpenStax, Principles of Marketing, 2.4 Marketing Plan Progress Using Metrics (market share in a category = the company’s sales ÷ the total sales in the category; relative market share = your share ÷ your leading competitor’s share). https://openstax.org/books/principles-marketing/pages/2-4-marketing-plan-progress-using-metrics.

## FAQ

### What is market share?

Market share is the part of all the sales in a market that one company makes, written as a percent. A company with $1 million of sales in a $20 million market has a 5% market share.

### How do I calculate market share?

Divide your sales by the total sales in the market for the same period, and multiply by 100. Selling 4,500 units in a market of 30,000 units is 4,500 ÷ 30,000 × 100 = 15%.

### Should I use dollars or units?

Either, as long as your sales and the market total use the same one. A share in dollars and a share in units can differ: a company selling dearer products has a larger share of the dollars than of the units.

### What is relative market share?

Relative market share compares your share with your largest competitor's: your share divided by theirs, times 100. Because both shares are out of the same total, it is the same as your sales divided by theirs. Selling $1 million against the leader's $1.5 million is a relative market share of 66.67%.

### What does a relative market share above 100% mean?

It means you lead the market. If you are the largest company, compare yourself with the next largest: $6 million of sales against their $4 million is a relative market share of 150%.

### Where do I find the total market sales?

Industry associations, government statistics such as the U.S. Census Bureau's economic surveys, and market research reports publish market totals. Make sure the total covers the same products, region and period as your own sales.

## Sources

- OpenStax, Principles of Marketing, 2.4 Marketing Plan Progress Using Metrics: market share in a category is the company's sales divided by the total sales in the category; relative market share is your share divided by your leading competitor's share, with the appliance store example. https://openstax.org/books/principles-marketing/pages/2-4-marketing-plan-progress-using-metrics (retrieved 2026-10-18)