A 60-point gain from 600 is a very achievable jump. I've watched students make moves of that size, and larger, many times over the years, and the ones starting around 600 who study effectively usually get there in well under six months. So, 6 months gives you room to work even with a full-time job and limited hours on weekdays.
Here's the caveat: 6 months of effective, structured study will get you from 600 to 660 with room to spare,while 6 months of grinding practice questions without diagnosing why you're missing them can leave you sitting at 600 the whole time.
So the realistic expectation is this: yes, six months is plenty, assuming you spend it learning the content deeply, topic by topic, and reviewing your errors seriously rather than just logging volume. At 600 you already have a real foundation. You're not building from scratch, you're closing specific gaps and tightening execution, and 60 points' worth of those gaps is a normal, very reachable target in that timeframe.
If you want a marker to track against, you're on pace if you're seeing steady movement on your official practice tests across the months, not a flat line. A flat line for weeks is your signal to change how you're studying, not to add more hours.
This article lays out realistic improvement expectations and what actually drives the gains:
How Much Can I Increase My GMAT Score?PurvaG
Asking for realistic expectations — not looking for 'it depends', genuinely want to hear timelines from people who've done it.