Introduction Emergency laparotomy is associated with significant morbidity and mortality. Accurate preoperative risk prediction is essential to guide clinical decision-making, allocate resources, and optimize patient counseling. We aimed to compare three commonly used risk calculators—the National Emergency Laparotomy Audit (NELA) tool, the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) calculator, and the New Zealand Surgical Risk Tool (NZSORT)—in predicting 30-day mortality following emergency laparotomy in a New Zealand cohort. Results A total of 312 emergency laparotomy procedures were performed on 291 patients. The 30-day mortality rate was 7.7% (24/312). NELA achieved the highest discrimination (AUC = 0.9057) and demonstrated good calibration (0.375). The ACS-NSQIP calculator showed similar discrimination (AUC = 0.8812) but moderate calibration (0.247). NZSORT had fair discrimination (AUC = 0.7467) and poor calibration (0.062). Conclusion In this cohort, NELA provided the most accurate estimates of 30-day mortality risk, closely followed by ACS-NSQIP. NZSORT performed less reliably in terms of both calibration and discrimination. These findings highlight the importance of validating and refining risk prediction tools for diverse clinical settings to improve perioperative planning and patient outcomes.