Rheumatology Calculators

30 calculators & risk scores

Browse 30 Rheumatology clinical calculators and risk scores used in everyday UK practice. Every tool runs entirely in your browser — enter the values and get instant scoring, colour-coded interpretation bands and a link to the underlying guideline or publication. ClinCalc Pro is free, needs no sign-up, and is built for working clinicians.

These rheumatology tools span Diagnosis, Prognosis, SLE, Rheumatoid Arthritis, Spondyloarthritis, Inflammatory Arthritis and more.

DAS28 — Disease Activity Score (RA)

Disease Activity Score in 28 joints for monitoring rheumatoid arthritis. Used to guide DMARD escalation and biologic eligibility.
CDAI — Clinical Disease Activity Index (RA)

Clinical Disease Activity Index for RA — does not require lab tests, making it useful at point of care.
ACR/EULAR Gout Classification Criteria 2015

ACR/EULAR 2015 classification criteria for gout. Score ≥8 classifies as gout.
ACR/EULAR SLE Classification Criteria 2019

2019 EULAR/ACR classification criteria for SLE: positive ANA (entry criterion), then weighted criteria in 7 clinical and 3 immunology domains — only the highest criterion in each domain counts. At least one clinical criterion and 10 or more points classify SLE. Count a criterion only if nothing explains it better than SLE; criteria need not occur at the same time.
Reactive Arthritis Criteria (Berlin 1999)

Simplified criteria for diagnosing reactive arthritis (formerly Reiter's syndrome). Asymmetric oligoarthritis following infection.
FRAX — Fracture Risk Assessment (Simplified)

FRAX estimates the 10-year probability of hip and of major osteoporotic fracture from clinical risk factors, with or without femoral-neck BMD, using country-specific models. This page explains how to use it.
CASPAR Criteria for Psoriatic Arthritis

Classification criteria for psoriatic arthritis (PsA). Requires inflammatory articular disease + score ≥3.
ACR/EULAR 2022 GPA Classification Criteria

2022 ACR/EULAR classification criteria for granulomatosis with polyangiitis (GPA): 10 weighted items (−5 to 17); a score of 5 or more classifies GPA. Apply only when small- or medium-vessel vasculitis has been diagnosed and mimics of vasculitis have been excluded.
SLEDAI-2K for SLE Disease Activity

Systemic Lupus Erythematosus Disease Activity Index 2000. 24-item weighted score measuring disease activity across 9 organ systems in the preceding 10 days.
2010 ACR/EULAR Classification Criteria for RA

2010 ACR/EULAR criteria for classifying definite rheumatoid arthritis. Score ≥ 6/10 = definite RA. Applicable to patients with ≥ 1 joint with clinical synovitis not better explained by another diagnosis.
BASDAI — Bath Ankylosing Spondylitis Disease Activity Index

6-question patient-reported outcome measuring disease activity in axial spondyloarthritis (ankylosing spondylitis). Score ≥ 4 indicates active disease — biologic eligibility threshold.
2012 ACR/EULAR Classification Criteria for Polymyalgia Rheumatica (PMR)

ACR/EULAR 2012 provisional criteria for classifying PMR in patients ≥50 years with new bilateral shoulder aching and elevated acute phase response. Score ≥4 (without USS) or ≥5 (with USS) = PMR classification.
2016 ACR/EULAR Classification Criteria for Primary Sjögren's Syndrome

2016 ACR/EULAR criteria for classifying primary Sjögren's syndrome in patients with ocular or oral dryness (or positive anti-SSA). Score ≥4 = primary Sjögren's syndrome.
ASAS Criteria for Axial Spondyloarthritis (Axial SpA)

Assessment of SpondyloArthritis International Society (ASAS) classification criteria for axial SpA in patients with chronic back pain ≥3 months onset age <45 years. Includes radiographic (AS) and non-radiographic axial SpA.
Jones Criteria for Acute Rheumatic Fever Diagnosis

Revised Jones criteria (AHA 2015) for acute rheumatic fever (ARF): evidence of preceding group A streptococcal infection plus 2 major, or 1 major and 2 minor manifestations (recurrent ARF: also 3 minor). Major and minor definitions differ for low-risk populations (ARF incidence ≤ 2 per 100 000 school-age children a year, or rheumatic heart disease prevalence ≤ 1 per 1000) and moderate/high-risk populations.
Cytokine Release Syndrome (CRS) Grading

ASTCT 2019 consensus grading of cytokine release syndrome (CRS) after CAR-T cells, bispecific antibodies or other immune effector cell therapies. Fever is required; the grade (1–4) is set by the more severe of hypotension and hypoxia. Guides management with tocilizumab and corticosteroids.
Patient Activity Scale II (PAS II) for Rheumatoid Arthritis

Patient-reported outcome measure for RA disease activity. Combines HAQ-II (disability) and patient global VAS. Score 0–10. Validated and recommended by ACR for routine RA monitoring. Correlates with DAS28 and CDAI.
2015 ACR/EULAR Gout Classification Criteria

2015 ACR/EULAR classification criteria for gout. Based on clinical, laboratory, and imaging evidence. Score ≥8 = gout classified. Gold standard = urate crystals in joint fluid, but scoring system available when unavailable.
Age-Adjusted ESR Upper Limit of Normal

Calculates age-adjusted upper limit of normal for Erythrocyte Sedimentation Rate (ESR). Rule: Male = age/2; Female = (age + 10)/2. Useful for PMR, GCA, and other inflammatory conditions where absolute ESR value may be misleading without age context.
DAS28-CRP (Disease Activity Score — Rheumatoid Arthritis)

Measures rheumatoid arthritis disease activity using 28 joint counts (tender and swollen), CRP, and patient global assessment. Guides DMARD therapy.
2010 ACR/EULAR Rheumatoid Arthritis Classification Criteria

Classifies rheumatoid arthritis using 2010 ACR/EULAR criteria. Score >=6 = definite RA. Replaces 1987 criteria; captures early RA.
SLEDAI-2K (SLE Disease Activity Index)

SLEDAI-2K (Gladman 2002): 24 weighted descriptors of lupus activity present at the visit or in the preceding 10 days (0–105). Tick every descriptor that is present.
BASDAI (Bath Ankylosing Spondylitis Disease Activity Index)

Patient-reported outcome measuring disease activity in ankylosing spondylitis and axial spondyloarthropathy. BASDAI >=4 indicates high disease activity.
PMR Diagnostic Score (EULAR/ACR 2012)

Classifies polymyalgia rheumatica (PMR) using EULAR/ACR 2012 provisional classification criteria. Score >=4 (without US) or >=5 (with US) = PMR.
CASPAR Criteria (Psoriatic Arthritis)

Classification criteria for psoriatic arthritis (PsA) using the CASPAR criteria. Score >=3 with inflammatory articular disease = PsA.
Birmingham Vasculitis Activity Score (BVAS)

Measures disease activity in ANCA-associated vasculitis (GPA, MPA, EGPA) across nine organ systems. Guides immunosuppressive therapy.
Reactive Arthritis (ReA) Diagnostic Criteria

Diagnoses reactive arthritis (formerly Reiter syndrome) using clinical triad and preceding infection evidence. Guides NSAID, antibiotic, and disease-modifying therapy.
QFracture — 10-Year Osteoporotic Fracture Risk

QFracture estimates the 10-year risk of hip fracture and of major osteoporotic fracture (hip, spine, wrist, shoulder) in people aged 30–99 from UK primary-care data. NICE CG146 recommends QFracture or FRAX for fracture risk assessment. This page explains how to use it.
JADAS-27 — Juvenile Arthritis Disease Activity Score

Composite disease-activity score for juvenile idiopathic arthritis (Consolaro 2009). JADAS-27 = physician global (0–10) + parent/patient global (0–10) + active joint count in 27 joints (0–27) + normalised ESR ((ESR − 20)/10, limited to 0–10). Range 0–57. Cut-offs differ for oligoarticular and polyarticular JIA.
SPADI — Shoulder Pain and Disability Index

Self-administered shoulder outcome measure (Roach 1991). 5 pain + 8 disability items, each scored 0–10 (NRS). Raw total /130; normalised to 0–100% by dividing by 130 and ×100. Higher = worse. Minimum clinically important difference ≈8 points.