Macronutrients, comprising carbohydrates, proteins and lipids, underpin many ecological processes, but their quantification in ecological studies is often inaccurate and laborious, requiring large investments of time and bulk samples, which make individual‐level studies impossible. This is a protocol for the direct, rapid and relatively low‐cost determination of macronutrient content from single small macroinvertebrates. Macronutrients are extracted by a sequential process of soaking in 1:12 chloroform:methanol solution to remove lipid and then solubilising tissue in 0.1M NaOH. Proteins, carbohydrates and lipids were determined by colorimetric assays from the same individual specimens. Macronutrient Extraction and Determination from Invertebrates (MEDI) can directly and rapidly determine macronutrient content in tiny (dry mass <1mg). Using MEDI, the total macronutrient content of over 50 macroinvertebrates can be determined within around 3days of collection at a cost of ~$1.35 per sample.