Find the highest score. This will be the benchmark for your curve. For instance, if the best-performing student scored an 88 out of 100 points, this will be your benchmark.
Subtract the highest score from 100. In our example, the highest score is 88. The difference is 12.
Add the difference to each of the remaining test scores. With this curving scheme, your top performer would earn a perfect 100. A student who earned a 73, meanwhile, would see her grade bumped up to a respectable 85.