I am also new here.
Just want to mention that this is in the woodworking forum. Perhaps that is why there is no replies.
Anyway, if the lot is rectangular you need to add the length of at least one side to your post.
With only the area as a fact the fence can be anywhere between 56 and "very very long" meters.

,is right, this should have been posted in another forum 🙂 ... as what he mentioned, you need to know the length and the width of your lot to be able to compute the perimeter fence needed for the whole lot ... e.g. a 200 sqm lot could be 20m on 1 side and 10m across which gives you a perimeter fence with a total length of 60m (20+20+10+10) less the opening for the entrance to the lot :-). as for the height, total height should be the number of CHB rows above ground and below ground (e.g. 2-3 rows)

note, all the old postings are under Building Materials ...

1. Hollow Blocks needed?
review the old posting "Estimating Construction Materials ... 1 sqm Wall of 4" CHB+Mortar (Cement + Sand) ... " to determine the number of CHB required for a 1 sqm wall (i think it's about 12.5 CHB per sqm wall) and the amount of cement/sand needed for it ... as for the rebar, this may change depending on your plan. the estimate was done with the rebar spacing of 0.5m for the vertical and horizontal 10mm rebar

2. size of Steel Bars?
review the old posting "Estimating Construction Materials ... Rebar (Footing, Columns, Beams, Slab, etc) ..." to determine the rebars required for the fence post which is basically a column with a footing. you need to talk to an architect, engineer, or an experience foreman as to how the fence post is to be done and how many is needed for your perimeter fence to be able to compute the rebars (including the stirups to tie the rebars into place for the post) that is needed. for a fence, i think you'll only need to use 9mm deforemed or 10mm. it all depends on the plan.

3. size of the posts fence?
as i mentioned above, you need to talk to an architect, engineer, or an experience foreman as to how the fence post is to be done. since your CHB is 4", then that's the smallest depth of your post or you can make a sqaure post. the critical thing is how deep should the post be below ground and it's footing which is dependent to the height of your fence.
review the old posting "Estimating Construction Materials ... Concrete (Cement + Sand + Gravel or Aggregate) " to determine the amount of concrete you will need for the fence post.

hope this info helps ... cheers

Boo!

parang pinaparegister pa ata yan bago mag fence? baka sila na mag aasikaso nyan or yung kukunsultahin mo na tao.