Neither test has a pass mark. Both produce a number that means nothing on its own and everything relative to the programmes you are applying to — which is why "what score do I need?" can only be answered after you have a shortlist, not before.
If you are still deciding whether to sit one at all, start with GRE and GMAT: Do You Actually Need Them?. This is about the number.
The total hides the thing that matters
A GRE total is made of verbal and quantitative sections scored separately. An engineering or computing programme will look hardest at the quantitative half; a humanities or policy programme at the verbal. A total that looks adequate can be built from a split that does not suit the department reading it.
The GMAT behaves the same way for business schools, which read the sections and the balance between them, not only the headline figure.
So the useful exercise is not "what is a good score" but: take your five or six target programmes, find what each publishes, and write down both the total and the section pattern. They vary more than students expect between departments of the same university.
"Average admitted score" is not a requirement
Many programmes publish no minimum and instead report the average of last year's admitted class. That number is widely misread as a bar. It is a description of who happened to be admitted, and half of them were below it.
What it does tell you honestly is where your application sits in the pile — which is useful for building a shortlist with ambitious, moderate and safe options rather than six of one kind.
Where the score actually earns its keep
Two places, and neither is admission in the ordinary case. A strong quantitative score can offset a weaker undergraduate record, which is the single most useful thing either test does for an Indian applicant with a modest percentage. And in the USA it feeds funding decisions — assistantships are frequently departmental, and the department reads the score.
A score that merely clears the bar changes very little. A score well above it can change what the degree costs you.
Test-optional, read carefully
A growing number of programmes are test-optional or have dropped the requirement. "Optional" is doing real work in that sentence: at a competitive programme an optional strong score still helps, and an optional absent score is a gap another applicant has filled with one.
The only reliable source is the programme's own admissions page for your intake. Policies have changed repeatedly in recent years, so a figure from two cycles ago is not evidence.
Practise before you book
Our GRE and GMAT hubs have free practice that scores you by section, which is the breakdown you need rather than a single number. It will not predict an official score — a short set cannot — but it will tell you which half is costing you the requirement.
And the score requirement checker shows typical requirements by course, so you can set a target before you start rather than after.