The current building stock for offices is very large, and is too large for the demand out of the market. Currently there is a total vacancy of 14.1% in the Netherlands, which is equal to 6.795.000 m2 of office space. In Amsterdam there is a total of 700.000 m2 which is structurally vacant and is considered hopeless in terms of fulfilling its function. In order to maintain their European and Worldwide tourism position and fulfilling their wish for an “Amsterdam Topstad” Amsterdam needs around 7500 new hotel rooms until the year 2015. Bringing the vacant office supply together with the demand for hotels is the scope of the thesis. Transformation of current vacant office buildings in Amsterdam to hotels could be a solution to a number of vacant office buildings. Setbacks of transformation projects are the technical and financial feasibility. Technical feasibility includes the state and dimensions of the current structure. The financial feasibility includes the difference in building value between developer and owner and the financial insecurity of transformation projects. The Master thesis is the result of researching the supply of vacant office buildings in Amsterdam and brings that together with the demand for hotel rooms. This will be done in two parts, the first being a modular room solution and the second one being a calculation tool to compare vacant office buildings to each other in their potential to transform to a hotel. The first handed solution in order to bring the vacant office supply with the hotel demand together is the design of the modular rooms; timber frame rooms with a low weight and a fixed price that can benefit the transformation into a hotel. The building speed will increase, fewer handlings on the building site will benefit risk management and the fixed price of the units will take away financial insecurity of transformation projects. The downsides to the modular element method lie in the transport and assembly of the units and the fact that using this solution implies that the façade needs to be replaced is a large financial factor. The set sizes of the elements make the solution somewhat inflexible and sensitive to loss of space. The Transformation Performance Coefficient is a calculation tool that will bring the current state and location of the building together with the future demands of the hotel. By adding a score to each of the 69 characteristics a coefficient will result from the program that can be used to compare different buildings on their potential to transform to a hotel function. The downsides of the tool are that the tool needs a second layer of scoring making one characteristic (such as the location of the hotel) more important than the other (such as the floor height) that are now of the same importance and that the program doesn’t take connections between characteristics into account.