When assesing oil palm productivity over periods of less than a year, the direct use of bunch harvest data, normally available as monthly totals of FFB yield is inadequate as much of the dry matter in a bunch may be formed prior to the month of harvest. Also, as is widely recognized, the higher energy content of bunches compared with vegetative tissue needs to be allowed for. To take account of these factors, a simple model was constructed based on monthly FFB yields, final bunch composition, growth curves of bunch components and component energy contents, to allow the bunch ‘non-oil equivalent’ dry matter production (BDMP) achieved each month to be calculated. The model was applied to data from two sites over several seasons. BDMP estimates from the model showed similar, but displaced, cyclic patterns to FFB, and gave smoother curves with lower CVs. Although based on a fixed bunch growth rate throughout the year, the results proved insensitive to growth duration and were similar for growth periods ranging from 130 to 190 days.