Starting this summer, GCSE grades A* to G will be gradually replace by grades numbered from nine to one.
However, around 70 per cent of more than 400 parents and pupils surveyed by the exams regulator Ofqual did not understand the system.
In addition, Ofqual research with 50 human resources professionals revealed that less than half of them understood the new system, while among small businesses, this figure dropped to about a fifth.
This has prompted Ofqual to start a publicity drive to increase awareness, which includes a series of online workshops for teaching staff in schools and universities.
This summer candidates who sit new more challenging English and maths GCSEs will receive a mixture of number and letter grades, and by the summer of 2018 a mix of numbers and letters will be awarded in an additional 20 subjects. The letter system will be entirely phased out by 2019.
"We don't want there to be any surprises in summer 2017. It's really important that we spread the word that GCSE grades are changing from letters to numbers," said Chief Regulator Sally Collier.
England’s councils are warning of a "ticking time bomb" in the special educational needs and disabilities (SEND) system, with new data showing deficits that could bankrupt local authorities within three years.
The regulations have been set following a second consultation and detailed collaborative working with organisations and people across deaf and hearing communities.
The Education Committee has published a letter to the Secretary of State for Education asking for more detail about the Department for Education’s work on developing its SEND reforms.
New analysis by NFER has highlighted the uneven distribution of pupils with special educational needs and disabilities (SEND) across mainstream schools in England.