Resource allocation in High Performance Computing (HPC) settings is still not easy for end-users due to the wide variety of application and environment configuration options. Users have difficulties to estimate the number of processors and amount of memory required by their jobs, select the queue and partition, and estimate when job output will be available to plan for next experiments. Apart from wasting infrastructure resources by making wrong allocation decisions, overall user response time can also be negatively impacted. Techniques that exploit batch scheduler systems to predict waiting time and runtime of user jobs have already been proposed. However, we observed that such techniques are not suitable for predicting job memory usage. In this paper we introduce a tool to help users predict their memory requirements using machine learning. We describe the integration of the tool with a batch scheduler system, discuss how batch scheduler log data can be exploited to generate memory usage predictions through machine learning, and present results of two production systems containing thousands of jobs.