Losses of peat mass as a result of peat oxidation is often related to peatland subsidence that subsequently used in practices to estimate green house gas emission. This logics will result in an overestimate of C loss as the peat subsidence is not only due to the loss of peat, but also due to compaction and dewatering of peat. Verification of C loss as peatland subsidence requires a fraction parameter of peatland subsidence due to peat compaction. The study emphasized on analysis of peat hydro-physics data collected on various types of peatland uses to estimate a fraction of peatland subsidence due to peat compaction and dewatering. The peat subsidence could be described proximately through peat compaction as a function of moisture content. At spesific moisture content of > 2 dm3 kg-1, the subsidence due to peat compaction dan dewatering proportionally could be described with a modified equation of Groenevelt and Grant (2004). Fraction of peat compaction due to dewatering contributed 85 – 95%, and this condition is approximately related with groundwater depth of 20 – 40 cm. When the groundwater depth drops down more that 40 cm, its fraction decreases to 20 – 50%. Subsequently a fraction of C loss could be estimated.