The Standards and Testing Agency has published key stage two scaled score conversion tables for 2016 and 2017, which should be used to convert raw scores in the 2016 and 2017 key stage two national curriculum tests to scaled scores.
The tables show each of the possible raw scores on the key stage two tests. To convert each pupil's raw score to a scaled score, look up the raw score in the appropriate year's table and read across to the appropriate scaled score. A scaled score of 100 or more shows the pupil has met the expected standard in the test.
The 2016 scaled score conversion table is available here.
The 2017 scaled score conversion table is available here.