The difference between the actual amount of materials used in production and the standard amount of materials allowed for the actual output, multiplied by the standard price per unit of materials is the materials variance.

The materials variance is a measure used in cost accounting to show the difference between the actual amount of materials used in production and the standard amount that should have been used, given the actual output. It is calculated by multiplying this difference by the standard cost per unit of materials.

Here are the steps to calculate it:

1. Determine the actual amount of materials used in production. This information can usually be found in the production records.

2. Determine the standard amount of materials that should have been used for the actual output. This information is usually based on predetermined standards, such as industry averages or company-specific benchmarks.

3. Subtract the standard amount from the actual amount to find the difference. If the result is positive, it means that more materials were used than should have been (i.e., there was inefficiency). If the result is negative, it means that less materials were used than should have been (i.e., there was efficiency).

4. Multiply this difference by the standard cost per unit of materials. This gives you the materials variance.

5. Analyze the materials variance. If it's positive, it means that the cost of materials was higher than expected. If it's negative, it means that the cost of materials was lower than expected. This can help managers identify areas where they can improve efficiency and reduce costs.