Frailty Assessment · Rockwood 2005 · 9 Levels · CFS 1–9 · NEJM Validated

Clinical Frailty Scale (CFS) Calculator — Rockwood 9-Level Frailty Rating

Assign a CFS score from 1 (Very Fit) to 9 (Terminally Ill) using validated Rockwood descriptors with detailed functional criteria. Takes 1–2 minutes. Assess based on pre-morbid status (2 weeks before illness), not current acute state. CFS ≥5 = frailty confirmed.

NMClinically reviewed byNikhil Mahajan, PT, MPT · Aug 17, 2026

⚠️ Clinical tool — assess pre-morbid functional status, not current acute presentation. The CFS should reflect the patient's usual health and function before the current illness. In hospital settings, this requires informant history from a family member or carer. Results must be interpreted by a qualified clinician alongside full clinical assessment. This tool does not replace clinical judgment.

1 – 3FitNo frailty

4VulnerablePre-frail

5 – 6Mild–Moderate FrailFrailty ≥5

7 – 9Severe–TerminalHighest risk

21%Mortality Risk/ptPer 1-point increase

How to use: Select the single description that best matches the patient's usual pre-morbid health status (last 2 weeks before the current illness). Use informant history when patient self-report is unreliable.

Selected CFS—/9

Frailty LevelNot selected

Frail (≥5)?—

Prognosis—

1. Very Fit Robust, active, energetic, motivated. Exercises regularly. Among the fittest for their age.

2. Well No active disease symptoms, but less fit than CFS 1. Exercises or is active occasionally (e.g. seasonal).

3. Managing Well Medical problems are well controlled, but not regularly active beyond routine walking.

4. Vulnerable Not dependent for daily help, but symptoms often limit activities. Common complaint is being 'slowed up' or tired.

Pre-frail

5. Mildly Frail Limited dependence on others for high-order IADLs (finances, transport, heavy housework, medications). Slower pace.

Mild Frailty

6. Moderately Frail Needs help with all outside activities and housekeeping. Indoors, has difficulty with stairs and bathing. May need minimal assistance with dressing.

Moderate Frailty

7. Severely Frail Completely dependent for personal care regardless of cause (physical or cognitive). Stable and not at high risk of dying in 6 months.

Severe Frailty

8. Very Severely Frail Completely dependent, approaching end of life. Typically, could not recover even from a minor illness.

Very Severe Frailty

9. Terminally Ill Approaching the end of life. This category applies even if the patient otherwise looks well. Life expectancy < 6 months.

Terminal

What Is the Clinical Frailty Scale?

A 84-year-old woman is brought to the emergency department by ambulance following a fall at home. She is currently confused and unable to provide a reliable history. Her daughter, reached by phone, reports that her mother has been slowing down over the past year — she no longer goes outside alone, needs help with housekeeping, and requires reminders for medications, but still manages personal care independently with minimal assistance for bathing. Based on this informant history, the senior clinician assigns a Clinical Frailty Scale score of 6 — Moderately Frail — which immediately informs the triage team about her frailty status, prognosis, and appropriate care pathway, before any investigation results are available.

The Clinical Frailty Scale (CFS) was developed by Kenneth Rockwood and colleagues at Dalhousie University, Halifax, and validated in a landmark study published in the New England Journal of Medicine in 2005. It is a 9-level ordinal scale from 1 (Very Fit) to 9 (Terminally Ill) that classifies frailty based on clinical descriptors of overall health, activity, and functional dependence. The CFS takes 1–2 minutes to administer and requires no equipment, making it the fastest standardised frailty assessment available. For a more detailed multi-domain assessment when specific intervention planning is required, see the Edmonton Frail Scale.

How to Score the CFS — Level-by-Level Guide

Select the single description that best matches the patient's usual pre-morbid status in the 2 weeks before the current illness — not their current acute presentation. When the patient cannot reliably self-report, use informant history from a family member, carer, or GP.

Score	Level	Key Descriptor	Frailty	Prognosis
1	Very Fit	Robust, active, energetic, motivated. Exercises regularly. Among the fittest for their age…	Not Frail	Excellent
2	Well	No active disease symptoms, but less fit than CFS 1. Exercises or is active occasionally (…	Not Frail	Very Good
3	Managing Well	Medical problems are well controlled, but not regularly active beyond routine walking.	Not Frail	Good
4	Vulnerable	Not dependent for daily help, but symptoms often limit activities. Common complaint is bei…	Pre-frail	Moderate
5	Mildly Frail	Limited dependence on others for high-order IADLs (finances, transport, heavy housework, m…	Mild Frailty	Moderate–Poor
6	Moderately Frail	Needs help with all outside activities and housekeeping. Indoors, has difficulty with stai…	Moderate Frailty	Poor
7	Severely Frail	Completely dependent for personal care regardless of cause (physical or cognitive). Stable…	Severe Frailty	Very Poor
8	Very Severely Frail	Completely dependent, approaching end of life. Typically, could not recover even from a mi…	Very Severe Frailty	Very Poor — End of Life
9	Terminally Ill	Approaching the end of life. This category applies even if the patient otherwise looks wel…	Terminal	Terminal

Clinical Significance of the CFS

The original Rockwood et al. (2005) NEJM study followed 2,305 community-dwelling older adults and demonstrated a clear, statistically significant dose-response relationship between CFS score and all-cause mortality over 5 years. Each 1-point increase in CFS score was associated with approximately 21% increased hazard for death after adjustment for age, sex, and education — making it one of the most powerful single-item predictors of mortality in older adults. Patients classified as Severely Frail (CFS 7) had hazard ratios approximately 2.0–2.5 times higher than those classified as Very Fit (CFS 1–3).

Beyond mortality, CFS scores predict a range of adverse outcomes in both community and acute settings: hospitalisation risk, length of stay, complications from surgical and medical interventions, discharge destination, and quality of life trajectory. This breadth of predictive validity explains why the CFS has been adopted in acute hospital admissions, ICU triage, surgical preadmission, and cancer care settings across the UK, Canada, Australia, and beyond.

The CFS is particularly powerful in acute settings because it captures pre-morbid trajectory — the patient's health trend before the current illness. Two patients admitted with identical acute presentations can have radically different prognoses based on their baseline frailty. A CFS 3 patient with an acute pneumonia has a fundamentally different recovery trajectory than a CFS 7 patient with the same admission diagnosis, and this difference would not be visible in traditional admission risk scores that focus solely on the acute condition.

When to Use This Calculator

Emergency department admission — rapid frailty triage for all patients aged 65 and above as recommended by NHS England, RCEM, and BGS guidance
Surgical preadmission — CFS identifies frail patients at elevated operative risk for enhanced peri-operative monitoring and shared decision-making about surgical vs non-surgical management
Medical ward admission — baseline frailty documentation for discharge planning, care pathway selection, and MDT communication
ICU and critical care — CFS was used extensively during COVID-19 triage and is embedded in many UK hospital critical care frailty policies
Oncology and cancer services — frailty assessment prior to systemic anti-cancer treatment to identify patients at elevated treatment toxicity risk
Advance care planning — CFS 7 and above indicates appropriate timing for goals-of-care discussion and advance directive completion

Important Scoring Guidance — Pre-Morbid Status

The most common CFS administration error is assessing current acute status rather than pre-morbid functional level. A patient admitted with delirium secondary to sepsis may appear CFS 8 based on current observation — but was functioning at CFS 4 before admission. Scoring the current acute state would overestimate frailty and potentially lead to inappropriate limitation of treatment. The CFS reflects where the patient was, not where they are right now. Always clarify the timeframe explicitly: "I am asking about what she was like in the 2 weeks before she became unwell."

Clinical Perspective: The CFS in Acute Clinical Practice

The Clinical Frailty Scale's clinical contribution is not primarily its predictive power — it is the standardisation of frailty communication between clinicians. Before tools like the CFS, frailty was either not assessed at all or described in idiosyncratic language that varied between clinicians, teams, and settings: "she's quite frail," "he's a good historian," "medically robust for her age." These phrases are not reproducible, not comparable, and not documentable in a way that transfers meaningful information. The CFS converts subjective clinical impression into a shared, reproducible, transferable language.

In acute hospital settings, this standardisation has direct care process benefits. An ED nurse assigning a CFS score on arrival, a surgical registrar reviewing preadmission frailty status, and a discharge planner reviewing care needs postoperatively are all working from the same validated scale — a frailty trajectory that follows the patient through the care pathway rather than being re-assessed de novo at each handover. This continuity of frailty information reduces both redundant reassessment and the risk that frailty is simply not documented at a critical decision point.

The scale's design also reflects an important conceptual choice: it assesses overall health trajectory rather than any single functional or biological marker. A patient who is wheelchair-bound due to severe rheumatoid arthritis but otherwise cognitively intact, nutritionally adequate, and socially engaged is not the same frailty phenotype as a patient with mild mobility limitation, early dementia, weight loss, and social isolation — even if both cannot walk independently. The CFS captures the accumulated deficit model of frailty (Rockwood and Mitnitski, 2007) rather than the physical phenotype model (Fried et al., 2001), making it more applicable across the heterogeneous range of older adult presentations seen in acute and community settings.

For clinicians newer to formal frailty assessment, the most productive starting practice is to score every older patient on admission — not just those who appear frail — and then review the scores at discharge. The mismatch between initial clinical impression and CFS score is often informative: it is frequently in the patients who appear "well" on first encounter that a careful CFS assessment reveals underlying vulnerability that an acute illness has temporarily masked.

Written by Nikhil Mahajan, PT, MPT · Clinically reviewed August 17, 2026 · MedicalCalculatorHub

Clinical Frailty Scale — Score Reference Table

CFS	Level	Functional Description	Frailty	Clinical Action
1	Very Fit	Robust, active, energetic, motivated. Exercises regularly. Among the fittest for their age.	No Frailty	No specific intervention needed. Encourage maintenance of activity.
2	Well	No active disease symptoms, but less fit than CFS 1. Exercises or is active occasionally (e.g. seaso…	No Frailty	Health promotion and preventive care.
3	Managing Well	Medical problems are well controlled, but not regularly active beyond routine walking.	No Frailty	Optimise medical management. Encourage regular activity.
4	Vulnerable	Not dependent for daily help, but symptoms often limit activities. Common complaint is being 'slowed…	Pre-frail	Comprehensive geriatric assessment. Falls prevention. Medication review.
5	Mildly Frail	Limited dependence on others for high-order IADLs (finances, transport, heavy housework, medications…	Mild Frailty	OT/PT referral. Exercise program. Home support assessment.
6	Moderately Frail	Needs help with all outside activities and housekeeping. Indoors, has difficulty with stairs and bat…	Moderate Frailty	Home care services. Multidisciplinary team assessment. Care coordinator involvement.
7	Severely Frail	Completely dependent for personal care regardless of cause (physical or cognitive). Stable and not a…	Severe Frailty	Comprehensive geriatric assessment. Goals-of-care discussion. Palliative care consideration.
8	Very Severely Frail	Completely dependent, approaching end of life. Typically, could not recover even from a minor illnes…	Very Severe Frailty	Advance care planning. Palliative care. Family conference regarding goals.
9	Terminally Ill	Approaching the end of life. This category applies even if the patient otherwise looks well. Life ex…	Terminal	Palliative and end-of-life care. Advance directives. Comfort-focused care planning.

Frequently Asked Questions — Clinical Frailty Scale

What is a CFS score of 5 vs 6 — how do they differ clinically?

CFS 5 (Mildly Frail) describes a patient who is slower than CFS 4, with limited dependence in high-order IADLs (finances, transportation) but independent in ADLs. CFS 6 (Moderately Frail) describes a patient who needs help with all outside activities and with housekeeping, but is independent in personal care — they can get dressed, bathe, and manage transfers alone. The key clinical distinction is outdoor independence: CFS 5 patients can manage outside with difficulty; CFS 6 patients cannot manage outside independently. This distinction has direct implications for discharge planning, as CFS 6 patients almost always require home care or supported accommodation on discharge.

Can the CFS be used in patients with dementia?

Yes, with an important modification. In patients with dementia, the CFS score is determined by their cognitive and functional decline trajectory, not by their physical fitness alone. A patient who is physically mobile but requires full assistance for all ADLs due to advanced dementia would score CFS 6–7 based on their functional status, not their walking ability. This is consistent with the CFS principle that frailty is measured by overall health status and functional trajectory. The original Rockwood 2005 study included cognitive impairment as a recognised frailty domain within the scale.

Is the CFS validated for use in acute hospital settings?

Yes. The CFS has been specifically validated in acute and emergency settings as a rapid frailty identification tool. UK NHS guidance recommends CFS assessment for all patients aged 65 and over admitted to hospital. In the COVID-19 pandemic, the CFS was widely adopted for acute medical triage and critical care allocation decisions due to its speed and reliability. However, clinicians should note that the CFS measures pre-morbid frailty status — what the patient was like before this acute illness — not their current acute clinical state. The assessment should be based on baseline function in the 2 weeks before the acute admission.

What is the mortality risk associated with each CFS level?

The original Rockwood et al. (2005) NEJM study demonstrated a clear dose-response relationship between CFS score and mortality over 5-year follow-up in community-dwelling older adults. Each 1-point increase in CFS was associated with approximately 21% increased hazard for all-cause mortality after adjustment for age, sex, and education. CFS 7 (Severely Frail) had hazard ratios of approximately 2.0–2.5 for mortality compared to CFS 1–3. In acute hospital settings, CFS scores of 7 and above are associated with significantly elevated in-hospital mortality rates.

Should the CFS be based on current status or pre-admission status?

Pre-admission status. The CFS specifically measures the patient's usual, stable health and function prior to the acute illness that brought them to hospital — ideally based on their status in the 2 weeks before admission. Assessing current acute status would confound frailty assessment with illness severity. A patient who is bedridden due to an acute pneumonia is not necessarily CFS 8 — they may be CFS 4 pre-morbidly, which is the clinically relevant information for prognosis and care planning. Informant history from a family member or caregiver is often the most reliable source for pre-morbid CFS assessment.

How does the CFS relate to the Edmonton Frail Scale?

Both assess frailty in older adults but serve different purposes. The CFS is a single-item global rating (1–9) that takes 1–2 minutes, making it ideal for rapid triage and acute settings. The Edmonton Frail Scale is a 9-domain multi-item assessment (0–17) that takes 10–15 minutes, providing domain-specific information to guide intervention. Use the CFS when you need rapid frailty triage and a standardised global classification. Use the EFS when you need to understand which specific domains are driving frailty and what targeted interventions are indicated.

What is the CFS score considered frailty?

CFS scores of 5 and above indicate frailty — mild (5), moderate (6), severe (7), or very severe (8). CFS 4 (Vulnerable) is pre-frailty — elevated risk but not yet frail by clinical definition. CFS 1–3 represent fit to managing well, with no frailty. CFS 9 (Terminally Ill) is a separate category for patients with a life expectancy under 6 months, regardless of frailty status. For clinical decision-making, CFS ≥5 is the commonly used frailty threshold, though some guidelines and studies use ≥4 for identifying vulnerable populations.

References

1. Rockwood K, Song X, MacKnight C, et al.
A global clinical measure of fitness and frailty in elderly people.
Canadian Medical Association Journal. 2005;173(5):489–495.
PubMed: 16129869

2. Rockwood K, Mitnitski A.
Frailty in relation to the accumulation of deficits.
Journal of Gerontology: Medical Sciences. 2007;62(7):722–727.
PubMed: 17634318

3. Fried LP, Tangen CM, Walston J, et al.
Frailty in older adults: evidence for a phenotype.
Journal of Gerontology: Medical Sciences. 2001;56(3):M146–M156.
PubMed: 11253156

4. Darvall JN, Bellomo R, Paul E, et al.
Frailty in very old critically ill patients in Australia and New Zealand: a prospective cohort study.
BMJ Open. 2019;9(3):e025332.
PubMed: 30833303

The Clinical Frailty Scale is copyright Geriatric Medicine Research, Dalhousie University, Halifax, Canada. Reproduced with permission for clinical use. For commercial or research use, contact the Dalhousie University Technology Transfer Office.