NAFLD Fibrosis Score (NFS) Calculator
Calculate the NAFLD Fibrosis Score from age, BMI, diabetes/IFG status, AST, ALT, platelet count, and albumin. Screen for advanced liver fibrosis (F3–F4) in NAFLD/MASLD with validated cutoffs and exportable results.
Enter your details — results appear below after you calculate.
Demographics & body metrics
BMI is calculated automatically from height and weight for the NFS formula
Select Yes for type 2 diabetes, prediabetes, or IFG (fasting glucose 100–125 mg/dL) — adds 1.13 NFS points per the Angulo formula
Liver function & blood tests
Typical reference: 10–40 U/L
Typical reference: 7–56 U/L · must be > 0 for ratio
Typical reference: 150–400 ×10⁹/L
Typical reference: 3.5–5.5 g/dL (35–55 g/L)
How this NAFLD Fibrosis Score (NFS) calculator works
This tool computes the NAFLD Fibrosis Score (NFS)—a validated blood-based index for advanced liver fibrosis (F3–F4) in NAFLD/MASLD per Angulo et al. Hepatology 2007. NFS < −1.455 rules out advanced fibrosis (~93% NPV); NFS > 0.676 rules it in (~90% PPV); scores between are indeterminate and need FibroScan or specialist review.
Enter age, height and weight (BMI is calculated automatically), diabetes/IFG status, AST and ALT (U/L), platelet count (×10⁹/L or ×10³/µL), and albumin (g/dL or g/L) from your latest blood work.
Results include NFS value, full formula component breakdown, fibrosis category (rule out / indeterminate / rule in), AST/ALT ratio analysis, individual lab reference status, health score, clinical interpretation, FibroScan referral guidance, and PDF export. NFS is for patients with known or suspected fatty liver—not general population screening.
Pair with our Fatty Liver Risk, Metabolic Syndrome Risk, Diabetes Risk, and Insulin Resistance calculators for broader metabolic liver context. This is an educational screening tool—not a diagnosis. Seek hepatology care for high or indeterminate NFS. Emergency care for jaundice, vomiting blood, or severe abdominal swelling.
Quick reference: NFS < −1.455 rules out advanced fibrosis · −1.455 to 0.676 is indeterminate (needs FibroScan) · NFS > 0.676 suggests F3–F4 fibrosis. Scroll below for formula breakdown, worked examples, NFS vs FIB-4, FibroScan cutoffs, clinical screening guidance, diet and treatment options, common mistakes, and FAQs. Compare with our FIB-4 Liver Fibrosis Calculator when NFS is indeterminate.
NAFLD Fibrosis Score (NFS) Calculator – Advanced Liver Fibrosis Screening
Millions search "NAFLD fibrosis score", "NFS calculator", and "liver fibrosis blood test" each year. The NAFLD Fibrosis Score (NFS) is a validated formula that estimates the probability of advanced fibrosis—bridging fibrosis (F3) or cirrhosis (F4)—in non-alcoholic fatty liver disease (NAFLD/MASLD) using routine blood tests: age, BMI, diabetes/IFG, AST, ALT, platelets, and albumin. No biopsy required for initial screening. Our free calculator applies the Angulo et al. Hepatology 2007 formula with published cutoffs, component breakdown, clinical interpretation, and exportable results.
Pair results with our Fatty Liver Risk Calculator, Metabolic Syndrome Risk Calculator, Diabetes Risk Calculator, and Insulin Resistance Calculator for comprehensive metabolic liver health assessment.
Why Calculate the NAFLD Fibrosis Score?
NAFLD/MASLD affects roughly 25–30% of adults worldwide and can progress silently from simple fat accumulation to inflammation (NASH/MASH) and fibrosis. Advanced fibrosis increases risk of cirrhosis, liver failure, and hepatocellular carcinoma. NFS helps triage who needs urgent hepatology referral versus who can continue lifestyle management—with ~93% negative predictive value at the low cutoff and ~90% positive predictive value at the high cutoff in validation studies.
1What You Enter
Demographics & metabolic
- Age — years (18–100)
- BMI — calculated from height and weight
- Diabetes/IFG — type 2 diabetes, prediabetes, or impaired fasting glucose
Laboratory values
- AST & ALT — U/L from liver panel
- Platelet count — ×10⁹/L or ×10³/µL
- Albumin — g/dL or g/L
Example (Rule out — low fibrosis risk)
Age 42, BMI 28, no diabetes, AST 32, ALT 45, platelets 250, albumin 4.3 g/dL → AST/ALT 0.71 → NFS ≈ −2.87 — below −1.455, advanced fibrosis unlikely. Continue lifestyle optimization.
Example (Rule in — high fibrosis risk)
Age 62, BMI 35, diabetes yes, AST 78, ALT 52, platelets 145, albumin 3.4 g/dL → AST/ALT 1.50 → NFS ≈ 2.40 — above 0.676, high probability of advanced fibrosis. Hepatology referral advised.
2NFS Formula & Cutoffs
NFS = −1.675 + 0.037×age + 0.094×BMI + 1.13×(diabetes/IFG) + 0.99×(AST/ALT) − 0.013×platelets(×10⁹/L) − 0.66×albumin(g/dL)
| NFS range | Interpretation | Action |
|---|---|---|
| < −1.455 | Low probability of advanced fibrosis | Lifestyle care; routine monitoring |
| −1.455 to 0.676 | Indeterminate | FibroScan / hepatology referral |
| > 0.676 | High probability of advanced fibrosis | Urgent specialist evaluation |
3Understanding NAFLD Fibrosis Stages
| Stage | Description | NFS relevance |
|---|---|---|
| F0 | No fibrosis; steatosis only | Usually NFS < −1.455 |
| F1 | Mild perisinusoidal fibrosis | Often low NFS; reversible with weight loss |
| F2 | Moderate fibrosis | May be indeterminate NFS |
| F3 | Bridging fibrosis | Often NFS > 0.676 |
| F4 | Cirrhosis | High NFS; specialist surveillance required |
NFS vs Other Fibrosis Tests
| Test | Inputs | Best use |
|---|---|---|
| NFS (this calculator) | Age, BMI, diabetes, AST, ALT, platelets, albumin | NAFLD-specific; rule out/in advanced fibrosis |
| FIB-4 | Age, AST, ALT, platelets | General liver fibrosis screening; no BMI/albumin |
| FibroScan | Ultrasound elastography (kPa) | Gold-standard non-invasive staging when NFS indeterminate |
| Liver biopsy | Histology | Definitive diagnosis when non-invasive tests discordant |
Treatment & Lifestyle When NFS Is Elevated
- 7–10% weight loss — most effective intervention for early MASLD; reduces liver fat and fibrosis progression
- Mediterranean diet — limits fructose, refined carbs, and saturated fat; emphasizes olive oil, fish, vegetables
- 150+ min/week exercise — aerobic activity reduces hepatic steatosis independent of weight loss
- Glycemic control — optimize HbA1c in diabetes; GLP-1 agonists show fibrosis benefits in trials
- Avoid alcohol — even moderate intake worsens NAFLD
- Specialist therapies — resmetirom for F2–F3 MASH; hepatology-guided only
4How NFS Is Calculated — Step by Step
Full formula
NFS = −1.675 + 0.037×age + 0.094×BMI + 1.13×(diabetes/IFG) + 0.99×(AST/ALT) − 0.013×platelets − 0.66×albumin
Platelets in ×10⁹/L (same numeric value as ×10³/µL). Albumin in g/dL. Diabetes/IFG = 1 if yes, 0 if no. BMI is computed from height (cm) and weight (kg): BMI = weight ÷ height(m)².
What each variable contributes
| Variable | Coefficient | Effect on NFS |
|---|---|---|
| Age (per year) | +0.037 | Older age raises NFS slightly |
| BMI (per kg/m²) | +0.094 | Higher BMI raises NFS |
| Diabetes / IFG | +1.13 | Adds fixed 1.13 points if present |
| AST/ALT ratio | +0.99 × ratio | Ratio ≥1.0 strongly raises NFS |
| Platelets (×10⁹/L) | −0.013 × count | Lower platelets lower NFS mathematically |
| Albumin (g/dL) | −0.66 × level | Lower albumin raises NFS substantially |
Example (Indeterminate zone)
Age 55, height 168 cm, weight 90 kg (BMI 31.9), no diabetes, AST 50, ALT 40, platelets 200, albumin 4.0 g/dL → AST/ALT 1.25 → NFS ≈ −0.63 — indeterminate (−1.455 to 0.676). Cannot rule out or confirm advanced fibrosis; request FibroScan and hepatology review.
NFS Risk Categories — Rule Out, Indeterminate & Rule In
| Category | NFS cutoff | NPV / PPV | Typical fibrosis stage | Recommended action |
|---|---|---|---|---|
| Rule out | < −1.455 | NPV ~93% | F0–F2 (no/mild/moderate fibrosis) | Lifestyle care; annual LFTs |
| Indeterminate | −1.455 to 0.676 | Cannot exclude F3–F4 | F1–F3 possible (~32% of patients) | FibroScan; hepatology referral |
| Rule in | > 0.676 | PPV ~90% | F3–F4 (bridging fibrosis/cirrhosis) | Urgent specialist evaluation |
Sensitivity ~90% and specificity ~60% at the low cutoff; sensitivity ~67% and specificity ~97% at the high cutoff in the original Angulo cohort. NFS performs best at the extremes—indeterminate scores need elastography.
Understanding NAFLD, MASLD & NASH — Disease Progression
NAFLD (non-alcoholic fatty liver disease) is now often termed MASLD (metabolic dysfunction-associated steatotic liver disease), emphasising insulin resistance and metabolic syndrome as root causes. Simple steatosis is fat accumulation without significant inflammation—often reversible. NASH/MASH (steatohepatitis) adds inflammation and hepatocyte injury. Untreated, NASH can progress through fibrosis stages to cirrhosis and hepatocellular carcinoma. NFS specifically screens for advanced fibrosis (F3–F4) in patients who already have fatty liver—not for diagnosing steatosis itself.
| Stage | What happens | Reversible? | NFS role |
|---|---|---|---|
| Steatosis (F0) | Fat in liver cells; enzymes may be normal | Yes — lifestyle change | Usually NFS < −1.455 |
| NASH/MASH inflammation | Fat + inflammation; ALT/AST often elevated | Often — with 7–10% weight loss | Variable NFS |
| Fibrosis F1–F2 | Early scar tissue in liver | Partially reversible | Low or indeterminate NFS |
| Bridging fibrosis (F3) | Extensive scarring between portal areas | Limited — specialist care | Often NFS > 0.676 |
| Cirrhosis (F4) | End-stage scarring; impaired liver function | Not reversible — prevent progression | High NFS; HCC surveillance needed |
Understanding Each NFS Lab Variable
AST & ALT
Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) are liver enzymes released when hepatocytes are injured. In simple steatosis, ALT often exceeds AST. As fibrosis advances, mitochondrial AST rises and the AST/ALT ratio ≥ 1.0 becomes a fibrosis signal—adding up to ~1.0 NFS points per unit of ratio.
- Typical AST: 10–40 U/L
- Typical ALT: 7–56 U/L (men), 7–35 (women)
- Muscle injury and alcohol also raise AST
Platelet count
Platelets (thrombocytes) are produced in bone marrow and cleared by the spleen. In advanced liver disease, portal hypertension causes splenic sequestration and low platelets. NFS subtracts 0.013 points per ×10⁹/L—so thrombocytopenia mathematically lowers NFS, but may itself indicate serious liver disease.
- Normal: 150–400 ×10⁹/L
- <150 ×10⁹/L: thrombocytopenia — evaluate for fibrosis
- Enter as ×10⁹/L or ×10³/µL (same number)
Serum albumin
Albumin is the main protein synthesised by the liver. Low albumin reflects reduced synthetic function in advanced fibrosis or cirrhosis. Each 1 g/dL below normal subtracts 0.66 NFS points (increases score). Dehydration and nephrotic syndrome also lower albumin—interpret with clinical context.
- Normal: 3.5–5.5 g/dL (35–55 g/L)
- <3.5 g/dL: hypoalbuminemia — liver or nutritional cause
Age, BMI & diabetes
Older age and higher BMI independently associate with fibrosis progression in NAFLD cohorts. Type 2 diabetes and impaired fasting glucose (100–125 mg/dL) add a fixed +1.13 NFS points because insulin resistance accelerates hepatic scarring. Up to 70% of type 2 diabetics have coexisting fatty liver.
- South Asians: overweight BMI ≥23 kg/m² (WHO Asia-Pacific)
- Pair with our HbA1c Calculator
NFS vs FIB-4 — Which Fibrosis Score to Use?
| Feature | NFS (this calculator) | FIB-4 |
|---|---|---|
| Formula | Age, BMI, diabetes, AST/ALT, platelets, albumin | (Age × AST) ÷ (Platelets × √ALT) |
| Validated for | NAFLD/MASLD specifically | General liver fibrosis (HBV, HCV, NAFLD) |
| Low cutoff | < −1.455 (rule out F3–F4) | < 1.3 (rule out advanced fibrosis) |
| High cutoff | > 0.676 (rule in F3–F4) | > 2.67 (rule in advanced fibrosis) |
| Best practice | Use NFS first in NAFLD; if indeterminate, add FIB-4 and FibroScan for concordant staging | |
FibroScan & When NFS Is Indeterminate
Transient elastography (FibroScan) measures liver stiffness in kilopascals (kPa) using ultrasound shear wave—non-invasive and widely available in India (₹3,000–8,000 at most centres). When NFS falls in the indeterminate zone (−1.455 to 0.676), FibroScan is the recommended next step per AASLD and EASL guidelines.
| FibroScan (kPa) | Fibrosis stage | Clinical meaning |
|---|---|---|
| < 7.0 | F0–F1 | No/significant fibrosis unlikely |
| 7.0–9.5 | F2 | Significant fibrosis possible |
| 9.5–12.5 | F3 | Advanced fibrosis — specialist care |
| > 12.5 | F4 (cirrhosis) | Cirrhosis likely — surveillance for HCC, varices |
Symptoms — When Fatty Liver Becomes Serious
Early / often silent
- No symptoms in 70–80% of NAFLD cases
- Mild fatigue or low energy
- Vague right upper abdominal discomfort
- Elevated ALT/AST on routine health check-up
- Fatty liver found incidentally on ultrasound
Advanced / urgent signs
- Unexplained weight loss
- Yellow eyes or skin (jaundice)
- Abdominal swelling (ascites)
- Dark urine, pale stools, easy bruising
- Confusion (hepatic encephalopathy) — emergency
High or indeterminate NFS with any advanced symptom warrants same-day medical evaluation—not watchful waiting.
NAFLD Fibrosis Screening in India
- Prevalence: NAFLD/MASLD affects ~25–30% of Indian adults—higher in urban, sedentary populations
- Diabetes overlap: ~77 million Indians with diabetes; up to 70% may have coexisting fatty liver
- Lower BMI risk: South Asians develop significant hepatic steatosis at BMI ≥23 (Asian overweight cutoff)
- Lean NAFLD: 10–20% of cases occur at normal BMI with high waist or poor diet quality
- Test costs: LFT panel ₹500–1,500; CBC ₹200–500; FibroScan ₹3,000–8,000 at major diagnostic centres
- Silent progression: Most advanced fibrosis is caught on corporate health panels, not from symptoms—NFS helps triage who needs FibroScan
- Diet drivers: Refined carbs, fried snacks, sugary beverages, and sedentary desk jobs accelerate fibrosis in Indian adults
Recommended Lab Panel for NFS Calculation
Gather these from a single fasting or non-fasting blood draw (NFS itself does not require fasting). Ask your doctor for a comprehensive metabolic liver workup:
- Liver function tests (LFTs): AST, ALT, GGT, bilirubin, alkaline phosphatase, albumin, total protein
- Complete blood count (CBC): platelet count (required for NFS)
- Fasting glucose & HbA1c: confirms diabetes/IFG status for NFS
- Lipid profile: triglycerides and HDL often elevated in MASLD
- Abdominal ultrasound: confirms hepatic steatosis if not already done
- FibroScan: if NFS is indeterminate or high
Pair with our Triglyceride/HDL Ratio Calculator, Cholesterol Risk Calculator, and BUN/Creatinine Ratio Calculator for broader metabolic and kidney assessment.
Diet & Weight Loss to Improve NFS Over Time
Sustained lifestyle change is the only proven intervention that reverses early fibrosis. Clinical trials show 7–10% body weight loss reduces liver fat, normalises enzymes, and can shift NFS toward lower values over 6–12 months.
- Mediterranean pattern: olive oil, fish, legumes, vegetables, whole grains
- Cut fructose: soft drinks, packaged juices, excess sweet chai, mithai
- Limit fried food: samosas, pakoras, restaurant deep-fried items
- Increase fibre: dal, vegetables, millets (jowar, bajra)
- 150+ min/week aerobic exercise: brisk walking, cycling, swimming
- Resistance training: 2×/week preserves muscle during weight loss
- Zero alcohol during active fibrosis management
- Recheck NFS 6–12 months after sustained lifestyle change
Medications & Conditions That Affect NFS Inputs
May raise AST/ALT
- Statins (usually mild, often continue safely)
- Methotrexate, amiodarone, isoniazid
- Paracetamol overdose
- Strenuous exercise before blood draw
- Non-alcoholic and alcoholic hepatitis flares
May lower platelets / albumin
- Portal hypertension (advanced fibrosis)
- Malnutrition, chronic illness
- Nephrotic syndrome (low albumin)
- Chemotherapy (bone marrow suppression)
- Autoimmune thrombocytopenia (unrelated to liver)
Always interpret NFS with your medication list and symptom timeline. Repeat abnormal labs after resolving acute illness before staging decisions.
MASH Treatment Options When Fibrosis Is Confirmed
- Resmetirom (Rezdiffra): FDA-approved for MASH with F2–F3 fibrosis; hepatology-prescribed only
- GLP-1 agonists: semaglutide, tirzepatide — weight loss plus emerging fibrosis benefits in trials
- Pioglitazone: evidence in selected nondiabetic and diabetic NASH patients (specialist decision)
- Vitamin E: non-diabetic NASH with biopsy-proven steatohepatitis (declining first-line use)
- Bariatric surgery: considered for BMI ≥35 with failed lifestyle intervention and significant fibrosis
Never start or stop liver medications based solely on calculator results. All pharmacotherapy requires hepatologist guidance after proper staging.
Common Mistakes When Using the NFS
1. Using NFS without confirmed fatty liver
NFS is validated in NAFLD/MASLD patients—not for screening the general population. Confirm steatosis on ultrasound or MRI first, or use our Fatty Liver Risk Calculator for initial screening.
2. Ignoring indeterminate scores
~32% of patients fall in the indeterminate zone. Do not assume mild disease—request FibroScan or hepatology referral rather than repeating NFS alone.
3. Dividing AST by ALT incorrectly
Use the same blood draw for both enzymes. ALT must be > 0. If ALT is very low, the ratio becomes unreliable—repeat labs when clinically stable.
4. Applying NFS in heavy alcohol use
NFS was validated in non-alcoholic fatty liver. Heavy alcohol (>14 units/week) invalidates interpretation—evaluate for alcoholic liver disease overlap with our Alcohol Impact Calculator.
5. Treating low NFS as a "healthy liver" guarantee
Low NFS excludes advanced fibrosis but not steatosis, inflammation, or early F1–F2 fibrosis. Continue lifestyle optimisation and periodic enzyme monitoring.
When to Seek Emergency Care
- Jaundice (yellow eyes or skin) with high NFS
- Vomiting blood or black tarry stools
- Severe abdominal pain or rapidly enlarging abdomen
- Confusion, drowsiness, or personality change (hepatic encephalopathy)
- Call 102 or 108 (India ambulance) or go to the nearest emergency department
Frequently Asked Questions (FAQs)
Related Calculators
You might also be interested in these related health and wellness calculators:

Fatty Liver Risk Calculator
Assess NAFLD/MASLD fatty liver risk from BMI, waist, diabetes, diet, alcohol and lifestyle. Get weight-loss targets, diet tips, exercise guidance, and liver test recommendations.

FIB-4 Liver Fibrosis Calculator
Calculate the FIB-4 index from age, AST, ALT and platelet count. Screen for advanced liver fibrosis (F3–F4) in NAFLD, viral hepatitis and chronic liver disease with validated cutoffs and PDF export.

Fatty Liver Severity Calculator
Calculate the Hepatic Steatosis Index (HSI) from ALT, AST, BMI, sex and diabetes status. Screen for fatty liver steatosis severity in NAFLD/MASLD with validated cutoffs and PDF export.

Metabolic Syndrome Risk Calculator
Screen metabolic syndrome with all 5 harmonized criteria—waist, triglycerides, HDL, blood pressure and fasting glucose. Asian waist cutoffs, diet tips, exercise guidance and lab recommendations.

Insulin Resistance (HOMA-IR) Calculator
Calculate HOMA-IR from fasting glucose and fasting insulin to estimate insulin resistance. Get category, HOMA-β, and educational guidance for metabolic health.

HbA1c ↔ Average Blood Glucose Calculator
Convert HbA1c (%) to estimated average glucose (eAG) and back using the ADAG formula. ADA category bands, mg/dL and mmol/L units, PDF export.

Type 2 Diabetes Risk Assessment Calculator
Assess type 2 diabetes risk using the Indian Diabetes Risk Score (IDRS). Enter age, waist, family history, activity, and clinical history. Low to Very High risk with PDF export.

Triglyceride/HDL Ratio Calculator
Calculate triglyceride/HDL ratio from fasting lipids for cardiometabolic risk, insulin resistance screening, AHA lipid interpretation, and PDF export.
Calculator Categories
Explore more free tools by health topic. Your calculator's category is highlighted below.
Body Composition
16 calculators
Browse categoryNutrition & Metabolism
31 calculators
Browse categoryFitness & Cardio
13 calculators
Browse categorySleep & Circadian Health
6 calculators
Browse categoryAging & Longevity
6 calculators
Browse categoryHeart & Metabolic Health
23 calculators
Browse categoryMental Wellbeing
4 calculators
Browse categoryWomen's Health
10 calculators
Browse categoryEnvironment & Lifestyle
6 calculators
Browse category