Market Share Calculator

The formula this calculator uses

Market share = your revenue / total market revenue

S

Your market share, as a fraction of the whole market

R

Your revenue over the period

M

Total revenue of the whole market over the same period

How to check the result by hand

1. 1

   Fix the market definition first

   Decide the category, the geography and the period, and hold all three fixed between the two periods you compare. Most bad share numbers come from a definition that drifted rather than from bad arithmetic.

2. 2

   Divide your revenue by the market total

   Use the same units and the same period on both sides. 48,000,000 over 1,200,000,000 gives 4 percent.

3. 3

   Compute the earlier period the same way

   40,000,000 over 1,100,000,000 gives 3.6364 percent. Recomputing the history with the current definition is worth the effort.

4. 4

   Take the difference in points, not percent

   The gain is 0.3636 percentage points. Saying the share rose 10 percent would be describing a percent of a percent and would mislead.

5. 5

   Check it against the two growth rates

   You grew 20 percent and the market grew 9.0909 percent, so gaining share is exactly what the arithmetic predicts. If the two disagree, one of the inputs is inconsistent.