Mandatory thresholds for the accuracy of reported energy on food and beverage product labels do not exist in many countries. Accurate nutrition information is essential for ensuring nutritional adequacy among hospital patients. The aim of this study was to compare direct measures of energy of nutritional fluids provided in hospitals to values determined via manufacturers’ specifications. Nutritional fluids were identified as any liquid provided to hospital patients orally, enterally or parenterally, to deliver nutrition. These were categorised into six groups aligned to food/medical standards, including (1) local recipes, (2) pre-packaged general fluids, (3) supplementary fluids, (4) prescribed nutrition fluids – thickened, (5) prescribed nutrition fluids – oral/enteral and (6) prescribed medical nutrition – intravenous (IV) and parenteral. An equivalence testing statistical approach (±10 % thresholds) was used to compare energy values derived directly via bomb calorimetry against those obtained from manufacturer specifications. A total of sixty-nine fluids were measured. One-fifth (n 14) exhibited non-equivalent energy values, with the majority of these (n 11; 79 %) likely to contain less energy than that calculated from reported values. Almost all (34/35; 97 %) prescribed nutrition fluids (oral/enteral (20/20; 100 %), IV and parenteral (7/7; 100 %) and thickened fluid (7/8; 88 %) products were equivalent. In contrast, only 21/34 (62 %) non-prescribed fluids (local recipes (2/11; 18 %), supplementary fluids (4/5; 80 %) and pre-packaged general fluid (15/18; 83 %) products) demonstrated equivalence. Energy content of nutritional fluids prescribed to hospital patients typically aligns with manufacturers’ values. Consumption of non-prescribed fluids may result in lower energy intakes than expected.