Most people I met have received their scores in around 9 days.
However, the GMAT says it takes about 3 weeks for them to release the scores!
If the application deadline is 20th Jan, when is a safe date to take the test?
It depends on the school - for many Jan 19th will be appropriate and as long as you can provide them with an un-official score that they can later verify, you are good. Check with your schools.
Otherwise, usually 14 days is very safe (97% probability).
Founder of GMAT Club
Just starting out with GMAT? Start here... | Want to know your GMAT Score? Try GMAT Score Estimator
Need GMAT Book Recommendations? Best GMAT Books
Co-author of the GMAT Club tests
Have a blog? Feature it on GMAT Club!