We searched for the best clinical support for daily practice with twin pregnancies. This retrospective study aim was to determine fetal growth standards separately for the bigger and smaller twin based on the group of potentially healthy neonates. Data of the live-born twin neonates born between the 25th and 40th week of gestation were collected. When comparing 50th percentiles for the same gestational period between bigger and smaller twins, the split is always close to 240 grams. The biggest split of the growth curves appears between weeks 31–35. The minimum weight gain for both twins was shown to be similar with ≥120g at weeks 27–24, and ≥140 at weeks 34–37. As compared, the medium fetal mass for summarized 50th centiles of the bigger vs smaller neonates were 2019.5g vs 1858.8g. Twin growth curves, especially for the bigger and smaller baby should be mandatory for daily clinical use.