NAFLD Fibrosis Score Calculator (fatty liver advanced fibrosis risk)

Understanding the NAFLD fibrosis score calculator — concept and principle

The NAFLD fibrosis score (NFS) estimates the chance of advanced liver scarring (fibrosis stage F3–F4) in people with fatty liver disease, using age, BMI, diabetes status and routine blood tests. Doctors use it to decide who needs further tests such as elastography (FibroScan) or specialist referral.

Six inputs, one score: with the default inputs the result is NFS −0.218 (indeterminate zone).

How it is calculated

NFS = −1.675 + 0.037 × age + 0.094 × BMI + 1.13 × (impaired fasting glucose or diabetes) + 0.99 × AST/ALT − 0.013 × platelets (×10⁹/L) − 0.66 × albumin (g/dL)

Diabetes or impaired fasting glucose = 1, otherwise 0.
Albumin in g/L is divided by 10.
Below −1.455: advanced fibrosis unlikely. Above 0.676: likely. In between: indeterminate.

The principle

Angulo and colleagues (2007) chose factors linked to scarring in a large group of patients with liver biopsies. Older age, higher BMI and diabetes reflect metabolic risk. As fibrosis advances, AST rises relative to ALT, the spleen enlarges and traps platelets so their count falls, and the liver makes less albumin. Combining them gives a score with two cut-offs: one to rule out and one to rule in advanced fibrosis.

Worked example

Default inputs: age 55, BMI 31, diabetes yes, AST 40, ALT 45, platelets 210, albumin 4.2 g/dL.

0.037 × 55 = 2.035; 0.094 × 31 = 2.914; diabetes 1.13.
AST/ALT = 40 ÷ 45 = 0.89; × 0.99 = 0.880.
−0.013 × 210 = −2.730; −0.66 × 4.2 = −2.772.
NFS = −1.675 + 2.035 + 2.914 + 1.13 + 0.880 − 2.730 − 2.772 = −0.218.
Between −1.455 and 0.676 → Indeterminate.

Each point is the calculator re-run with only “Albumin” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Albumin	NAFLD fibrosis score
1.05	1.861
2.1	1.168
3.15	0.475
4.2	-0.218
5.25	-0.911
6.3	-1.604
8.4	-2.99

How to read the result

Where does your result fall?

A low score makes advanced fibrosis unlikely, and follow-up in primary care is often enough. A high score suggests advanced fibrosis and specialist assessment. An indeterminate score usually leads to elastography. The score is less accurate under age 35, and over 65 a lower rule-out cut-off of about 0.12 is often used. Fatty liver disease is now also called MASLD.

Common mistakes

Entering albumin in g/L while the unit is set to g/dL.
Using it in liver disease from other causes such as viral hepatitis.
Treating an indeterminate result as reassuring.

Keep in mind: This is not a diagnosis. Fatty liver disease should be assessed and followed by a doctor.

Frequently asked questions

What NAFLD fibrosis score is normal?

Below −1.455 makes advanced fibrosis unlikely.

What is FIB-4?

Another score using age, AST, ALT and platelets; many guidelines use it as the first step.

Can fibrosis improve?

Yes. Weight loss and control of diabetes can reduce liver fat and, in some people, fibrosis.

Sources: Angulo P, Hui JM, Marchesini G, et al., "The NAFLD fibrosis score: a noninvasive system that identifies liver fibrosis in patients with NAFLD", Hepatology 2007;45(4):846–854

Checked 9 Nov 2026. Angulo P, Hui JM, Marchesini G, et al., “The NAFLD fibrosis score: a noninvasive system that identifies liver fibrosis in patients with NAFLD”, Hepatology 2007;45(4):846–854 — formula and cut-offs as tabulated in World J Hepatol 2015;7(11):1450, Table 3.

Your numbers