Example 1
- 3 P
- 4 S
Normalised matrix index: 46 / 100 | P×S product: 12
The calculator uses the numbers you enter. With 3 P, 4 S the result is Normalised matrix index: 46 / 100 | P×S product: 12. This is not an ISO 31000 matrix.
Risk matrix
The calculator uses the numbers you enter. With 3 P, 4 S the result is Normalised matrix index: 46 / 100 | P×S product: 12. This is not an ISO 31000 matrix.
This is not an ISO 31000 matrix. API exposure is on API exposure.
Result
Enter data.
How it works
Risk matrix in this calculator is P times S, then 1 to 25 mapped onto 0 to 100. With 3 P, 4 S the result is Normalised matrix index: 46 / 100 | P×S product: 12.
P×S = P × S. index = ((P×S − 1) / 24) × 100. The formula uses P×S and likelihood.
46 / 100 | P×S product: 12 is not an ISO 31000 matrix. Another set of numbers gives 13 / 100 | P×S product: 4, and a further set gives 100 / 100 | P×S product: 25. Empty optional fields do not change the result.
API exposure answers a different question. Fairness gap does too. Here 3 P, 4 S leave 46 / 100 | P×S product: 12.
Type 3 P, 4 S and click Calculate. Two more ready sets sit under the form: 13 / 100 | P×S product: 4 and 100 / 100 | P×S product: 25.
Other numbers on the same labels move the result. The first example gives 46 / 100 | P×S product: 12.
Formula
P×S = P × S. index = ((P×S − 1) / 24) × 100.
How to use
- Type 3 P, 4 S.
- Leave optional fields empty if you do not want them in the result.
- Click Calculate. This set shows Normalised matrix index: 46 / 100 | P×S product: 12.
- The second example under the result is Normalised matrix index: 13 / 100 | P×S product: 4, the third Normalised matrix index: 100 / 100 | P×S product: 25.
- This is not an ISO 31000 matrix.
Risk matrix = Normalised matrix index: 46 / 100 | P×S product: 12
The calculator uses the numbers you enter. With 3 P, 4 S the result is Normalised matrix index: 46 / 100 | P×S product: 12. This is not an ISO 31000 matrix.
- Risk matrix
- Risk matrix is this calculator's result. The first example is Normalised matrix index: 46 / 100 | P×S product: 12.
- P×S
- The formula includes P×S. The second example gives 13 / 100 | P×S product: 4.
- likelihood
- The formula includes likelihood. The second example gives 13 / 100 | P×S product: 4.
Examples
Example 2
- 2 P
- 2 S
Normalised matrix index: 13 / 100 | P×S product: 4
With 2 P, 2 S the result is Normalised matrix index: 13 / 100 | P×S product: 4.
Example 3
- 5 P
- 5 S
Normalised matrix index: 100 / 100 | P×S product: 25
With 5 P, 5 S the result is Normalised matrix index: 100 / 100 | P×S product: 25.
Related calculators
Common questions
What do you get from 3 P, 4 S?
Normalised matrix index: 46 / 100 | P×S product: 12. This is not an ISO 31000 matrix.
What about the second example?
Normalised matrix index: 13 / 100 | P×S product: 4.
What about the third example?
Normalised matrix index: 100 / 100 | P×S product: 25.
Is 46 / 100 | P×S product: 12 an ISO 31000 matrix?
No. It is the result from the numbers you enter.
Do empty fields change 46 / 100 | P×S product: 12?
No. Empty optional fields do not change the result.
How is this different from API exposure?
That calculator answers another question. Here Risk matrix stays at Normalised matrix index: 46 / 100 | P×S product: 12.
Does a comma in the number work?
Yes. A comma and a dot mean the same in a number field.
Is the result a diagnosis or official opinion?
No. The result comes from the numbers you enter. an ISO 31000 matrix sits outside this calculator.
Do 2 P, 2 S give Normalised matrix index: 13 / 100 | P×S product: 4?
Yes. That is the second example under the form.
How is the matrix index calculated?
The calculator multiplies likelihood P by impact S. The product from 1 to 25 is mapped onto 0 to 100 with ((P times S - 1) / 24) times 100. In the first example the result is Normalised matrix index: 46 / 100 | P×S product: 12.
What do P and S mean?
P is likelihood from 1 to 5. S is impact from 1 to 5. Both numbers are scores you enter, not measurements from a risk register.
Is this an ISO 31000 matrix?
No. The result is the product of two scores and a normalized index. The calculator is not an ISO 31000 matrix.
Why is the index not 0 when P = 1 and S = 1?
At product 1 the formula gives ((1 - 1) / 24) times 100, which is 0. At a larger product the index rises linearly to 100 at 25.
Can P and S be fractions?
The fields take numbers from 1 to 5. The formula multiplies them as entered; the page is built for whole scores from 1 to 5.
Knowledge sources
The terms come from EU acts. The calculator result is a sketch index, not a regulator decision.
Page updated in 2026.