Figuring out rehabbing formula

[Amir Khan]

I am new so forgive me if this has been discussed before. I am trying to understand whether there is general rule or rule of thumb formula to figure out percentage costs of a rehab project. Specifically figuring out percentage figures for soft cost and carrying costs for a project. Assuming the ARV, rehab cost and wholesale price of project are know. As an example:

ARV: $220K

PRICE: $158K

REPAIRS: $15K

LOAN AMOUNT: 70% of ARV plus repairs= (0.7 x 220,000)-15,000=$169,000

**** Soft cost (10%) of ARV= $22,000

**** Hard cost (5%) of loan amount ($169K)=$8450

Appreciate all suggestion and advise. Thanks.