Measurement errors often occur when students are doing practicum and there is a lack of digital-based tools, especially the use of IoT. The purpose of this research is to develop a calorimeter practicum tool based on the internet of things on temperature & heat materials. This research and development use the ADDIE development model. At the analysis stage, a needs analysis was carried out and the problems encountered. At the design stage, starting with the design of the practicum tool and application. In the development stage, the practicum tools that have been made are tested on material experts, media experts. In the implementation phase, a field test was conducted on a small scale 14 respondents. In the evaluation stage, it is done by analyzed expert validation data, small-scale and large-scale tests. Data obtained from the observation were analyzed descriptively qualitatively. While the validation data were analyzed descriptively qualitatively and quantitatively. The recapitulation score from material experts is 91.8% (very good), media experts are 90.9% (very good), small-scale test is 76.8% (good), large-scale test is 85.08% (very good). So, it can be concluded that the calorimeter practicum tool based on the internet of things is suitable for use in the learning process.