GFR Calculator

eGFR by CKD EPI 2021 · CKD stage · Creatinine clearance

Age (years)

Sex ?

Creatinine (mg/dL)

Cystatin C mg/L, optional

Weight (lb) ?

Urine ACR mg/g, optional

ℹ️

For adults 18 and older with stable kidney function. Use values from a lab report with standardized assays.

🩺 Enter age, sex, and serum creatinine to see your eGFR, CKD stage, and KDIGO risk category.

Estimated GFR

GFR category

Albuminuria

KDIGO risk

CKD EPI 2021 creatinine

CKD EPI 2021 creatinine + cystatin C

CKD EPI 2012 cystatin C

Cockcroft Gault CrCl

Creatinine converted

Creatinine at eGFR 60

Step by step

eGFR in mL/min/1.73 m², rounded to a whole number as NIDDK recommends.

eGFR by creatinine for your age and sex

KDIGO risk heat map (GFR × albuminuria)

GFR category	A1 <30 mg/g	A2 30 to 300	A3 >300

Green low, yellow moderately increased, orange high, red very high risk. Without kidney damage, G1 and G2 are not CKD.

What Is GFR and What Does This eGFR Calculator Show?

Glomerular filtration rate (GFR) is the volume of blood the kidneys filter each minute and the best overall index of kidney function. Measuring it directly needs an injected tracer, so labs estimate it from blood tests. The estimate, eGFR, is reported in mL/min/1.73 m², scaled to an average adult body surface area.

This calculator uses the race free 2021 CKD EPI equations that NIDDK and the National Kidney Foundation recommend. Enter creatinine to get eGFRcr. Add cystatin C and it also returns the combined creatinine and cystatin C estimate, which NIDDK describes as more accurate, and uses that value for staging.

Results include your KDIGO GFR stage, albuminuria category if you enter a urine albumin to creatinine ratio (ACR), KDIGO risk, and Cockcroft Gault creatinine clearance.

CKD EPI 2021 eGFR Formula

eGFR = 142 × min(Scr/κ,1)^α × max(Scr/κ,1)^−1.200 × 0.9938^age × 1.012 [female] Scr = serum creatinine in mg/dL κ = 0.7 female, 0.9 male α = −0.241 female, −0.302 male

Worked example: 55 year old man, creatinine 1.1

Scr/κ = 1.1 ÷ 0.9 = 1.222 min term = 1 (ratio is above 1) max term = 1.222^−1.2 = 0.786 age term = 0.9938^55 = 0.710 eGFR = 142 × 0.786 × 0.710 = 79.3 → 79 (G2)

To convert creatinine from µmol/L, divide by 88.4. A value of 97 µmol/L equals 1.10 mg/dL.

eGFR Chart by Creatinine and Age

eGFR in mL/min/1.73 m² from the 2021 CKD EPI creatinine equation, shown as men / women.

Creatinine	Age 30	Age 50	Age 70
0.7 mg/dL	127 / 119	112 / 105	99 / 93
0.9 mg/dL	118 / 88	104 / 78	92 / 69
1.0 mg/dL	104 / 78	92 / 69	81 / 61
1.2 mg/dL	83 / 62	74 / 55	65 / 49
1.5 mg/dL	64 / 48	56 / 42	50 / 37
2.0 mg/dL	45 / 34	40 / 30	35 / 26
3.0 mg/dL	28 / 21	25 / 18	22 / 16
5.0 mg/dL	15 / 11	13 / 10	12 / 9

The same creatinine gives a lower eGFR for women and for older adults, because women and older people generally produce less creatinine from muscle.

CKD Stages by eGFR and Albuminuria

KDIGO classifies chronic kidney disease by cause, GFR category (G), and albuminuria category (A). CKD means an eGFR below 60, or an ACR of 30 mg/g or higher or another marker of kidney damage, lasting at least 3 months.

Stage	eGFR	Description
G1	90 or higher	Normal or high
G2	60 to 89	Mildly decreased
G3a	45 to 59	Mildly to moderately decreased
G3b	30 to 44	Moderately to severely decreased
G4	15 to 29	Severely decreased
G5	Below 15	Kidney failure

Category	ACR mg/g	ACR mg/mmol
A1 normal to mild	Below 30	Below 3
A2 moderate	30 to 300	3 to 30
A3 severe	Above 300	Above 30

Risk rises with both lower eGFR and higher albuminuria. On the KDIGO heat map, G1 or G2 with A1 is low risk, G3a with A1 is moderately increased, G3b with A1 is high, and G4 or G5 is very high at any albumin level. An eGFR of 75 with an ACR of 400 mg/g is high risk, so both tests matter.

Other GFR Equations

Creatinine and cystatin C (2021)

135 × min(Scr/κ,1)^α × max(Scr/κ,1)^−0.544 × min(Scys/0.8,1)^−0.323 × max(Scys/0.8,1)^−0.778 × 0.9961^age × 0.963 [female] α = −0.219 female, −0.144 male 60 year old woman, Scr 0.9, Scys 1.0: 75

Cystatin C only (2012)

133 × min(Scys/0.8,1)^−0.499 × max(Scys/0.8,1)^−1.328 × 0.996^age × 0.932 [female] Same woman, Scys 1.0: 72

Cockcroft Gault creatinine clearance

CrCl = (140 − age) × kg ÷ (72 × Scr) × 0.85 [female] 55 years, 80 kg, Scr 1.1: 85 × 80 ÷ 79.2 = 86 mL/min

Children: bedside Schwartz

eGFR = 0.413 × height (cm) ÷ Scr 130 cm, Scr 0.6: 0.413 × 130 ÷ 0.6 = 89

eGFR by Age

eGFR falls with age even at the same creatinine. This table holds creatinine at 0.9 mg/dL for men and 0.7 mg/dL for women, the κ values in the equation.

Age	Men (0.9)	Women (0.7)
20	125	127
30	118	119
40	111	112
50	104	105
60	98	99
70	92	93
80	86	87

These are calculated values, not population norms. An eGFR of 60 to 89 is not CKD without albuminuria or another sign of kidney damage.

Some labs still report the older MDRD Study equation; NKF states CKD EPI is more accurate, especially at higher GFR.

Accuracy and Limitations

It is an estimate. NIDDK notes imprecision is inherent in every equation and recommends following trends rather than one result.
Bias. The race free 2021 creatinine equation overestimates GFR by about 4% in non Black people and underestimates it by about 4% in Black people on average. Adding cystatin C narrows this gap.
Muscle and diet. Creatinine comes from muscle, so bodybuilders and people with muscle wasting or unusual diets can get misleading results. Cystatin C helps here.
Unstable kidney function. The equations assume creatinine is steady and do not apply during acute kidney injury.
Trends matter. Compare results from the same equation; NIDDK notes a switch of equation can change eGFR with no change in kidney function.

Common Mistakes

Wrong unit. Entering 97 µmol/L as mg/dL gives an eGFR near 1. Check the unit on your lab report.
Treating one low value as CKD. CKD requires abnormal results for 3 months or more.
Ignoring urine tests. An eGFR above 60 does not rule out kidney damage. Ask about ACR if you have diabetes or high blood pressure.
Using it for children. Under 18, use a pediatric equation such as bedside Schwartz.

⚠️

CDC estimates 14% of U.S. adults, about 37 million people, have CKD, and about 9 in 10 do not know it. CKD affects about 38% of adults with diabetes and 21% with high blood pressure.

Frequently Asked Questions

What is a normal GFR?

90 or higher is normal or high (G1), and 60 to 89 is mildly decreased (G2). GFR declines with age: at a creatinine of 0.9 mg/dL a man's eGFR is about 118 at 30 and 92 at 70. Without kidney damage markers, 60 or more is not CKD.

What eGFR indicates kidney disease?

An eGFR below 60, or an ACR of 30 mg/g or higher, lasting 3 months or more. Stage 3a is 45 to 59, 3b is 30 to 44, 4 is 15 to 29, and 5, below 15, is kidney failure. One low result is usually repeated before a diagnosis.

How do you calculate eGFR?

Use the 2021 CKD EPI equation: 142 × min(Scr/κ,1)^α × max(Scr/κ,1)^−1.2 × 0.9938^age, times 1.012 for women. A 55 year old man with creatinine 1.1 gets 142 × 0.786 × 0.710 = 79.

What is the difference between eGFR and creatinine clearance?

eGFR is indexed to 1.73 m² and used for CKD staging. Cockcroft Gault creatinine clearance is in mL/min, depends on weight, and dates from 1976. Many drug labels still use it, so the two numbers can differ.

Why was race removed from the eGFR calculation?

The NKF and ASN Task Force recommended equations without race in 2021. The new equations use only age, sex, and lab values, and adding cystatin C narrows the remaining differences between groups.

Sources & References

National Kidney Foundation, CKD EPI Creatinine Equation (2021). kidney.org
NKF, CKD EPI Creatinine Cystatin Equation (2021) and Cystatin C Equation (2012). kidney.org, kidney.org
NKF, Stages of Chronic Kidney Disease and eGFR Calculator (ACR categories). kidney.org, kidney.org
NIDDK, Glomerular Filtration Rate Equations, reviewed May 2025. niddk.nih.gov
KDIGO CKD Work Group. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of CKD. Kidney Int 2024;105(4S):S117 to S314. doi.org/10.1016/j.kint.2023.10.018
Inker LA, et al. New Creatinine and Cystatin C Based Equations to Estimate GFR without Race. N Engl J Med 2021;385:1737 to 1749. doi.org/10.1056/NEJMoa2102953
Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron 1976;16:31 to 41. doi.org/10.1159/000180580
Schwartz GJ, et al. New equations to estimate GFR in children with CKD. J Am Soc Nephrol 2009;20:629 to 637. doi.org/10.1681/ASN.2008030287
CDC, Chronic Kidney Disease in the United States, updated March 2026. cdc.gov

Results are for informational purposes only and should not be used as a diagnosis or substitute for professional medical advice. Reference data reviewed: 2026.