Neutrophil-to-lymphocyte ratio (NLR) calculator
The neutrophil-to-lymphocyte ratio, or NLR, divides one white cell count on your blood count by another. Labs rarely print it, but it is easy to work out from the differential, the part of a complete blood count that splits white cells into types. Researchers use it as a cheap marker of inflammation and physical stress, and it turns up in studies of heart disease, infection, and cancer. It is not a diagnosis of any of them. Enter your absolute counts, or the two percentages, from the same blood draw.
The formula
NLR = absolute neutrophil count ÷ absolute lymphocyte count
The ratio has no unit, so any unit works as long as both counts use the same one. K/µL, 10^3/µL, and 10^9/L are the same number. If your lab prints cells/µL, such as 3,100, either enter both that way or divide both by 1,000.
The percentages give the same answer:
NLR = neutrophil % ÷ lymphocyte %
Both percentages are shares of the same total white count, so the total cancels out. A white count of 6.0 with 60% neutrophils and 25% lymphocytes gives counts of 3.6 and 1.5, and both 3.6 ÷ 1.5 and 60 ÷ 25 are 2.4. Use the two percentages from one report, not one from each of two draws.
| Neutrophils | Lymphocytes | NLR | Reading |
|---|---|---|---|
| 3.6 | 2.0 | 1.80 | Within the healthy range |
| 4.2 | 1.4 | 3.00 | Within the healthy range |
| 7.8 | 1.2 | 6.50 | Above the healthy range |
| 1.6 | 2.2 | 0.73 | Below the healthy range |
| 60% | 30% | 2.00 | Within the healthy range |
Counts in 10^9/L.
What’s a normal NLR
For a long time there was no reference range, and studies picked their own cutoffs. Forget and colleagues measured NLR in 413 working adults in good health, aged 21 to 66 with a median of 38, and found a mean of 1.65. Their range, covering 95% of healthy adults, was 0.78 to 3.53, and a second group of healthy volunteers measured on other analyzers fell inside it. The calculator reads your ratio against that range. It comes from adults who were not elderly, so it fits older adults less well.
Averages also differ between groups. Azab and colleagues looked at 9,427 US adults in the NHANES survey from 2007 to 2010, leaving out anyone taking steroids, chemotherapy, immune-suppressing drugs, or antibiotics. The average NLR was 2.15. It was 1.76 in non-Hispanic Black participants, 2.08 in Hispanic participants, and 2.24 in non-Hispanic White participants, and the authors suggested cutoffs may need to differ by ancestry. People who reported diabetes, heart disease, or smoking had higher ratios than those who did not.
Many healthy people of African and Middle Eastern ancestry have a lower neutrophil count with no added risk of infection, tied to the Duffy-null blood group. A lower neutrophil count gives a lower ratio, so a ratio near the bottom of the range can be ordinary. How to track your hemoglobin and CBC over time covers the Duffy-null neutrophil range.
What a high or low NLR can mean
Neutrophils tend to rise with acute stress, infection, and inflammation, and lymphocytes tend to fall with the same things. The ratio moves when either does, so it can jump further than either count alone. That makes it sensitive, and also unspecific. A high ratio fits a bacterial infection, a recent surgery or injury, a hard illness, or a course of steroids just as well as any chronic disease. In a study of patients taking prednisone, neutrophils rose while lymphocytes fell, which pushes the ratio up from both ends.
A low ratio means a low neutrophil count or a high lymphocyte count. On its own it can be a healthy person’s normal, as with the Duffy-null pattern above. If either count is flagged on the report, that count is the thing to ask about.
In research, a raised NLR before treatment is linked to worse outcomes in several cancers and in heart disease, which is why it shows up in so many papers. Those findings are about groups of patients. They don’t turn one person’s ratio into a risk score.
One value is noisy
Neutrophils are among the most variable counts on a CBC. In the European Biological Variation Study, within-person variation for the neutrophil count ran 12 to 20%, as the CBC tracking post covers. A ratio of two counts carries the noise of both, so it swings more between healthy draws than either count does. A single high ratio during a cold says little. A ratio that sits higher across several calm draws, or that climbs steadily, says more.
When the calculator differs from your report
- Rounding. Labs round the counts before printing them. Dividing rounded counts can shift the ratio in the second decimal.
- Different draws. Neutrophils and lymphocytes from different days don’t make a ratio.
- Bands. Some manual differentials list band neutrophils separately. Ask your lab whether the neutrophil line includes them.
NLR in HealthViewer
HealthViewer is a lab results tracker that runs on your own computer. It imports blood counts from lab report PDFs, MyChart downloads, and direct connections to your health system, and charts each test over time in Trends.
To chart NLR, write your own derived test:
with A as your absolute neutrophil count (HealthViewer files it as Neutrophils
Absolute), B as your absolute lymphocyte count (Lymphocytes #), a date
window of 0 days, and No unit as the result unit, the expression is A / B. After
Recompute All, it’s calculated for every draw that has both counts, so the line shows
your own baseline.
Add a journal entry for an illness, a surgery, or a steroid
course, then turn on Show journal to see it on the chart.
Everything stays in an encrypted file on your computer, with no account and no cloud service. Getting Started walks through the first import.
This calculator is for understanding your lab results, not for diagnosis or treatment. NLR is a nonspecific marker. Talk to your clinician about a result that worries you.