According to certain embodiments, a method in a network node (100A) for determining spectrum utilization for a plurality of numerologies transmitted within an allocated bandwidth includes selecting one or more of the plurality of numerologies. For each of the one or more selected numerologies, a spectrum utilization is determined. The spectrum utilization is based on the spectrum utilization that would be achieved if the selected numerology was transmitted across the allocated bandwidth. A physical resource block (PRB) allocation is calculated based on the allocated bandwidth and the spectrum utilization.