Nurse-to-Patient Ratio Calculator
Calculate nurse-to-patient ratios and compare to safe staffing guidelines.
Enter total patients and nurses on shift to see the ratio by hospital unit type.
The nurse-to-patient ratio is the number of patients assigned to each registered nurse during a shift. It is one of the most studied variables in patient safety research, and the evidence is consistent: lower ratios (fewer patients per nurse) reduce mortality, complications, and nurse burnout.
Ratio = Total Patients / Nurses on Shift
A ward with 30 patients and 6 nurses has a ratio of 1:5 — each nurse is responsible for 5 patients.
California was the first US state to mandate minimum ratios under AB 394, which took effect in 2004. These are the strictest standards in the country and are widely used as a benchmark:
- Intensive Care Unit (ICU): 1:2
- Step-down / Progressive Care Unit: 1:3
- Emergency Department: 1:4
- Medical-Surgical / General Ward: 1:5
- Postpartum / Pediatrics: 1:6
- Psychiatric: 1:6
- Operating Room (circulating RN): 1:1
The 2002 study by Linda Aiken in JAMA found that each additional patient per nurse was associated with a 7% increase in 30-day patient mortality. This figure is frequently cited in staffing policy debates.
Nurse-to-patient ratio does not capture the full picture. Patient acuity (how sick each patient is), non-nursing tasks (paperwork, transport), and skill mix (ratio of RNs to LPNs to aides) all affect the actual workload per nurse.
This calculator helps charge nurses, administrators, and advocates quickly check whether a given shift is staffed within guideline limits.