Capital Gain tax is same in both partnership and AOP.
As per The Pune Bench of the Income -tax Appellate Tribunal (the Tribunal) in the case of Ashok Gordhandas
Kirpalani (the taxpayer) held that contribution of land to Association of Person (AOP) formed for joint
development of property is not transfer of capital asset under Section 45(3) of the Income - tax Act, 1961 (the Act) but is the case of joint pooling of resources by different parties. Therefore, security deposits received against the contribution made by the taxpayer is not taxable as capital gain.
where the asset held by the taxpayer has not been transferred to the AOP, there is no question of charging any income from capital gains in the hands of the taxpayer in this regard under section 45(3) of the Act.
Link of Full case law is given below:
In partnership firm as capital is getting converted into stock in trade, capital gain will be calculated for partners at the time of such conversion.
Section 45(2) of Income Tax Act deals with the cases where a capital asset is converted into stock in trade. Whenever a capital asset is converted into stock in trade by an assessee it is deemed as transfer of capital asset and attracts capital gain provisions, in spite of the fact that the ownership of such capital asset doesn’t change by such conversion.
Section 2(47)(iv) while defining the term “Transfer” in relation to a capital asset provides for that it includes “in a case where the asset is converted by the owner thereof into, or is treated by him as, stock-in-trade of a business carried on by him, such conversion or treatment”
From the plain reading of section 45(2) and 2(47)(iv) above it is clear that if a capital asset is converted into stock in trade of a business carried on by the assessee then it is considered as a transfer of such capital asset and capital gain or loss as the case may be shall be computed in the year of sale of such converted capital asset. The consideration in such case for the purpose of computing capital gain/loss shall be equivalent to the fair market value of such asset as existing on the date of such conversation.
CIT Vs Trivedi (1988)172 ITR 95(Bombay)
A person acquired land with a view to selling it later after developing it and divided the land into plots and sold the same in parcels, the activity could only be described as a business venture.
so you need to calculate capital gain depending on the date of ownership of each owner.