Surgical Outcome Risk Tool v2 (SORT)

Main Group

Sub Group

Procedure Description


Minor   Intermediate   Major    Xmajor/complex


1   2   3   4   5


Elective   Expedited   Urgent    Immediate

Thoracics, gastrointestinal or vascular surgery

Yes   No


Yes   No


<65   65-79   >79

Clinical Risk Assessment

Please select the clinical estimate of 30-day mortality; this should ideally be an assessment made by senior clinicians in the Multi-disciplinary perioperative care team.


The SORT uses some information about patient health and the planned surgical procedure to provide an estimate of the risk of death within 30 days of an operation. The percentages provided by the SORT are only estimates taking into account the general risks of the procedure and some information about the patient, but should not be confused with a patient-specific estimate in an individual case. As with all risk prediction tools, not every factor which may affect outcome can be included, and there may well be other patient-specific and surgical factors which may influence the risk of death significantly.

This resource is not intended to be used in isolation for clinical decision making and should not replace the advice of a healthcare professional about the potential risks or benefits of a planned procedure. Neither the Surgical Outcomes Research Centre (SOuRCe) or the National Confidential Enquiry into Patient Outcome and Death (NCEPOD) are responsible for decisions made by healthcare professionals or patients which are based on the estimates provided by the SORT, as these estimates are provided only for the purposes of background information.

Healthcare professionals should not rely on, nor act upon, the mortality risk percentage without reviewing it and using it in conjunction with their clinical judgement/knowledge and as part of their overall toolkit.

Patients should always consult a healthcare professional in decision-making about their health and treatment.

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User notes

All values must be present before the calculation can take place.

Surgical severity will be calculated automatically on entry of procedure details.

If the procedure you are searching for is not listed, please use the nearest available procedure for calculation.

We support open research and coding. If modifying the tool and/or formula (remix, transform or build upon it), the calculator cannot be called SORT. Furthermore, we cannot be held responsible for any technical errors that might occur in your final product.

About SORT

The SORT is a preoperative risk prediction tool which estimates the risk of death within 30 days of inpatient surgery.

The original SORT model and this website were developed as a collaboration between NCEPOD researchers (Karen Protopapa and Neil Smith; and clinicians working within the UCL/UCLH Surgical Outcomes Research Centre (

Since the SORT model was originally published, several papers have re-evaluated it in different cohorts and for different purposes.

The most recent large-scale update (published in PLOS Medicine in 2020 and based on data collected in the UK, Australia and New Zealand) supports the new SORT-clinical judgment model over the original SORT model. Additionally, and unlike the original SORT model, this new model demonstrates good accuracy in neurological/spinal and cardiothoracic surgery.

Our recommendation is that the new combined-SORT clinical judgement model is used, and the clinical estimate provided by senior decision-makers and (ideally) the multi-disciplinary team.

Further Information

Intellectual property: the SORT equations are available from open access peer-reviewed publications. Please cite these as appropriate:

PLOS Medicine 2020 - development and validation of SORT-clinical judgement model

British Journal of Surgery 2014 - development and validation of original SORT model

If you experience any problems then please