CKiD Calculators

CKiD Under 25 (U25) GFR estimating equations

Two formulas intended for use with children, adolescents and young adults 1-25 years old are provided here: one based on height and creatinine, the other based on cystatin C. Both formulas require age and sex to be specified. If only height and serum creatinine are available, the former calculator will be used; if only cystatin C is available, the later will be used. If height, serum creatinine and cystatin C are provided, estimates using each of the two formulas will be displayed.

This calculator is derived from Pierce et al. 2021.

U25 Statistical Software

Researchers may download the files below to implement U25 GFR estimation in R, SAS, STATA and Excel.

The U25 Calculator is also available as an online and mobile app through Calculate by QxMD.
To access the U25 calculator in the Calculate app, you will need to navigate to :

  • Nephrology
  • then “eGFR
  • and then click on “CKiD U25 eGFR calculator

Pediatric CKiD Kidney Replacement Therapy Risk Calculator on

This calculator provides estimated times to when a patient diagnosed with CKD may require kidney replacement therapy (KRT; i.e., transplant or dialysis). These estimates are based on a set of variables that are routinely measured on patients. This calculator is designed for use in pediatric patients with chronic kidney disease and an estimated glomerular filtration rate (GFR) of <90 mL/min/1.73m².

This calculator is not intended for use in patients with kidney transplants.

The tool requires information on current markers of kidney health: CKD diagnosis, GFR and proteinuria. Additional input variables may be included to improve prediction, including blood pressure category, anemia, serum albumin, serum chloride, serum bicarbonate and GFR from approximately one year ago. Not all additional variables are required for a valid estimate of time to KRT.

Please interpret the estimated times within the context of the patient’s full clinical profile.

This calculator is based on data from the Chronic Kidney Disease in Children (CKiD) study and the publication:

Ng DK, Matheson MB, Schwartz GJ, Wang FM, Mendley SR, Furth SL, Warady BA, for the CKiD Investigators. Development of an adaptive clinical web-based prediction tool for kidney replacement therapy in children with chronic kidney disease. Kidney International. Published online June 28, 2023:S0085-2538(23)00474-X. doi:10.1016/j.kint.2023.06.020.

Please direct questions and feedback to Derek Ng, PhD (

Go to Calculator on (

Acknowledgements: We thank Dr. Ryan Town for collaborating to develop the online calculator on

Estimating Time to ESRD in Children with CKD

This calculator can be used to estimate time to ESRD in children with CKD using diagnosis, GFR, and urine protein-to-creatinine ratio.

This calculator was developed based on Furth et al. 2018