SOFA Score Calculator (Sequential Organ Failure Assessment)

Background.

The SOFA score grades six organ systems — respiration, coagulation, liver, cardiovascular, central nervous system and renal — from 0 to 4 each, giving a total from 0 to 24. It describes the burden of organ dysfunction at a point in time. It is a clinical aid for clinicians, not a diagnosis, and the US federal ASPR TRACIE guidance on the score is blunt about its limits: SOFA "was designed to look at populations, and not individual patients", and it "cannot accurately predict which patients will survive".

That limitation is why this page reports the component breakdown as prominently as the total. A SOFA of 8 built from a respiratory 4 and a coagulation 4 is a different patient from a SOFA of 8 spread evenly across six systems. The total is a research and triage summary; the breakdown is the clinical picture.

The score's modern role comes from Sepsis-3, which defines organ dysfunction as an acute increase in the total SOFA score of two points or more consequent on infection, with the baseline assumed to be zero in a patient not known to have pre-existing organ dysfunction. Note carefully that the criterion is a change, not a total. A patient with chronic organ dysfunction and a standing SOFA of 6 who arrives with a SOFA of 6 has not met it. This calculator therefore takes a baseline as an input and reports the change alongside the total.

The thresholds implemented here were taken verbatim from the ASPR TRACIE table, which prints its provenance as Vincent and colleagues, 1996, and which gives both mg/dL and µmol/L columns. That second column turned out to matter. A widely circulated reproduction of the SOFA table renders the renal creatinine bands as 2.0 to 2.9 for a grade of 2 and 3.0 to 5.0 for a grade of 3. The correct bands are 2.0 to 3.4 and 3.5 to 4.9, and the µmol/L column proves it: 171 to 299 µmol/L is 1.93 to 3.38 mg/dL and 300 to 440 µmol/L is 3.39 to 4.98 mg/dL. A creatinine of 3.0 mg/dL therefore grades 2, not 3. The same reproduction also claims the total ranges from 6 to 24; it ranges from 0 to 24, because every system can score 0.

Two implementation details change results and are easy to miss. First, respiratory grades 3 and 4 require respiratory support: a PaO₂/FiO₂ ratio below 200 in a patient who is not being ventilated or otherwise supported caps at 2. Second, the renal grade is the higher of the creatinine grade and the urine-output grade, because the published table joins them with "or" — a patient with a normal creatinine passing 400 mL a day scores 3 on renal.

The cardiovascular component is entered here as a grade from 0 to 4 rather than derived from a dose, and that is a deliberate choice. The published tiers leave a vasopressor dose of exactly 0.1 µg/kg/min unassigned, they require the agent to have been running for at least an hour, and TRACIE itself notes that some of the listed agents — low-dose dopamine, dobutamine — are no longer used routinely. Grading it at the bedside is honest; inferring it from a number would not be.

Finally, two warnings that TRACIE raises directly. A raised baseline creatinine, and especially pre-existing end-stage renal disease, falsely elevates the score relative to actual mortality. And sedation makes the central nervous system component hard to assess, which is a routine problem in exactly the ventilated patients the score is most often applied to. Neither is a reason to abandon the score; both are reasons to read the components rather than the total.

What is sofa score calculator?

SOFA — the Sequential Organ Failure Assessment, originally the Sepsis-related Organ Failure Assessment — is a six-system scoring instrument published by Vincent and colleagues in Intensive Care Medicine in 1996. Each system is graded from 0 (normal) to 4 (most abnormal), so the total runs from 0 to 24.

It was designed as a research tool, so that groups of critically ill patients could be described and compared by their degree of organ dysfunction. Its practical appeal is that it needs only six data points, most of which are already available in an intensive care chart.

Its prominence today comes from the 2016 Sepsis-3 consensus, which uses an acute rise in SOFA of two points or more as the operational definition of organ dysfunction in sepsis. That made a research score into a definitional one, and it is why so many clinicians who never used SOFA before 2016 now calculate it.

What it is not: a diagnosis, a screening tool, a prediction of survival for an individual patient, or something that can be inferred from a qSOFA score. It also performs poorly in isolated respiratory failure — few patients with primary respiratory failure generate SOFA scores above 4 to 6, which limits its usefulness in a respiratory pandemic and can bias triage against patients with other conditions.

How to use this calculator.

1. 01Enter the PaO₂/FiO₂ ratio in mmHg — arterial PaO₂ divided by the inspired oxygen fraction expressed as a decimal, so 90 mmHg on 0.4 gives 225.
2. 02Answer the respiratory support question honestly: grades 3 and 4 require it, so a ratio below 200 in an unsupported patient caps at 2.
3. 03Enter the platelet count in ×10³/µL, the bilirubin in mg/dL and the creatinine in mg/dL. Divide a µmol/L bilirubin by 17.1 and a µmol/L creatinine by 88.4 first.
4. 04Grade the cardiovascular component from 0 to 4 using the tiers printed on the field. The doses are in µg/kg/min and apply to agents running for at least an hour.
5. 05Enter the Glasgow Coma Scale total. If the patient is sedated, note that the component is unreliable and record that alongside the score.
6. 06Enter the 24-hour urine output. The renal grade is the higher of the creatinine grade and the urine grade.
7. 07Enter a baseline SOFA if the patient has known pre-existing organ dysfunction; otherwise leave it at 0, as Sepsis-3 directs.
8. 08Read the component breakdown, not just the total, and read the change from baseline when the question is whether Sepsis-3 organ dysfunction is present.

The formula.

SOFA is the sum of six organ grades, each 0 to 4, so the total runs from 0 to 24. Respiration is graded on the PaO₂/FiO₂ ratio: 400 or above scores 0, below 400 scores 1, below 300 scores 2, below 200 with respiratory support scores 3, and below 100 with respiratory support scores 4. Coagulation is graded on platelets in ×10³/µL: 150 or above scores 0, below 150 scores 1, below 100 scores 2, below 50 scores 3, below 20 scores 4. Liver is graded on bilirubin in mg/dL: below 1.2 scores 0, 1.2 to 1.9 scores 1, 2.0 to 5.9 scores 2, 6.0 to 11.9 scores 3, 12.0 and above scores 4. The central nervous system is graded on the Glasgow Coma Scale: 15 scores 0, 13 to 14 scores 1, 10 to 12 scores 2, 6 to 9 scores 3, below 6 scores 4. Renal is graded on creatinine in mg/dL — below 1.2 scores 0, 1.2 to 1.9 scores 1, 2.0 to 3.4 scores 2, 3.5 to 4.9 scores 3, 5.0 and above scores 4 — or on urine output, where below 500 mL per day scores 3 and below 200 mL per day scores 4, whichever is higher. Cardiovascular is entered directly as a grade from 0 to 4.

Rounding stage: there is none anywhere. Every entered value is compared against its threshold exactly as entered, so a bilirubin of 1.99 mg/dL grades 1 and 2.00 grades 2. Rounding 1.95 up to 2.0 would silently raise an organ grade, and by extension the total and possibly the Sepsis-3 verdict. Each organ grade, the total and the change from baseline are all exact integers.

The published table has open intervals at the top of the liver and renal scales — it prints "above 12.0" and "above 5.0" for a grade of 4 — which leaves exactly 12.0 and exactly 5.0 unassigned. This calculator implements those as 12.0 or above and 5.0 or above, with every lower band bounded by a strict comparison on the next threshold, so the scale has no gaps over the real numbers.

The Sepsis-3 verdict is computed on the change, not the total. The total minus the entered baseline is compared against 2: an increase of 2 or more meets the criterion. That means a patient with a chronically elevated baseline can carry a high total without meeting it, and a previously well patient can meet it at a total of 2.

Worked through the example on this page: a PaO₂/FiO₂ of 240 on mechanical ventilation is below 300 but not below 200, so respiration grades 2. Platelets of 88 are below 100, so coagulation grades 2. A bilirubin of 2.4 mg/dL is in the 2.0 to 5.9 band, so liver grades 2. Noradrenaline at 0.08 µg/kg/min sits in the third cardiovascular tier, entered as 3. A Glasgow Coma Scale of 13 is in the 13 to 14 band, so the central nervous system grades 1. A creatinine of 2.1 mg/dL is in the 2.0 to 3.4 band giving 2, and a urine output of 700 mL per day gives 0, so renal takes the higher and grades 2. The total is 2 + 2 + 2 + 3 + 1 + 2 = 12, and with a baseline of 0 the change is 12, which meets the Sepsis-3 criterion.

A worked example.

Frequently asked questions.

References& sources.

1. [1]Vincent JL, Moreno R, Takala J, et al. The SOFA (Sepsis-related Organ Failure Assessment) score to describe organ dysfunction/failure. Intensive Care Medicine. 1996;22(7):707–710. The derivation of the six-system 0–4 score. (Publisher full text paywalled; consulted 2026-07-29. The complete table used here comes from the federal reference below, which names this paper as its source.)
2. [2]ASPR TRACIE (US Department of Health and Human Services, Office of the Assistant Secretary for Preparedness and Response). SOFA Score: What it is and How to Use it in Triage. Updated 21 December 2020. Source of the complete SOFA table implemented here — extracted verbatim from the official PDF, printed with the provenance line "Source: Vincent et al., 1996" and with both mg/dL and µmol/L columns — and of the limitation statements quoted on this page. (Retrieved 2026-07-29.)
3. [3]Singer M, Deutschman CS, Seymour CW, et al. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016;315(8):801–810. Source of the organ dysfunction definition used by the verdict output: an acute change in total SOFA of 2 points or more consequent on infection, with baseline assumed 0 in patients not known to have pre-existing organ dysfunction. (Consulted 2026-07-29.)
4. [4]Evans L, Rhodes A, Alhazzani W, et al. Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock 2021. Crit Care Med. 2021;49(11):e1063–e1143. Consulted for how sepsis scores are and are not used for screening, and cross-referenced from the companion qSOFA page. (Retrieved 2026-07-29.)