applied science EXTENDED CERTIFICATE

how much to get an overall merit?
there is 6 units

Before answering your question can I just double-check it's the Extended Certificate you're taking? I know you put that it all caps, but you also said it contained 6 units. It contains 4 according to the specification.

no this is pearson i do aqa

Understood. The AQA Level 3 Extended Certificate in Applied Science does indeed have 6 units. Unlike the Pearson BTEC version, all units are equally weighted - which makes things a lot simpler.

For each of the three internally-assessed units (units 2, 5 and 6a/b/c), there are 25 criteria against which you're being assessed. Each criterion you hit earns you 4 UMS points. (Don't worry about what UMS stands for; it's not important or relevant.) So you could gains 100 UMS points per unit, in theory.

For the three externally-assessed units (units 1, 3 and 4), each exam is out of 60 marks. These marks are them translated to UMS points out of 100. The way these are translated varies each year, in the same way that grade boundaries move around each year for GCSEs. Again, you could gain 100 UMS points per unit.

If you get a total of 360 UMS points across all six units then you get a Merit overall. (That's 60% of the maximum UMS points available.)

Each unit is also awarded a unit grade of Near Pass, Pass, Merit or Distinction. In addition to the total UMS points, you also need to get at least a Pass in 4 units and at least a Near Pass in the other two. So if you got 525 UMS points by getting a perfect score in 5 units, and just 25 UMS points in the last unit, you wouldn't even get a Pass overall.

If any of the above is unclear, just let me know.

Wait I’m sooo sorry but it’s a bit unclear
so In terms of merit pass and distinctions per units, what’s the least I can get in everything overall ( grade wise not points) to get an overall merit

You don't get an overall grade based upon what unit grades you got. The unit grades are pretty much irrelevant (other than the fact that they give you a clue as you the points you achieved per unit). It's the UMS points which count.

If you insist on looking at unit grades only, then just make sure you get a Merit in each and every unit. If you get a Pass in one, try to compensate by getting a Distinction in another. That isn't the way it actually works, but it might be easier to understand.

Oh no.. I got one pass and the rest merits

Oh no.. I got one pass and the rest merits

I think if you got high merits then you can still get a Merit overall