Urea conversion: to convert urea from mmol/L to mg/dL, multiply by 6.006 (about 6). To convert urea mmol/L to BUN (blood urea nitrogen) in mg/dL, multiply by 2.8. Example: urea 7 mmol/L = 42.0 mg/dL urea = 19.6 mg/dL BUN.
Urea Calculator
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Using BUN? This calculator gives urea in mg/dL. For BUN in mg/dL, multiply mmol/L by 2.8 or use the BUN mg/dL to mmol/L converter.
Urea vs BUN: Which One Is on Your Report?
Urea and BUN measure the same waste product, but they are reported differently, and using the wrong factor is the most common urea conversion mistake:
- Urea in mmol/L is used in the UK, Europe, Australia, Nigeria and many other countries (called ureum in Indonesian and Dutch reports).
- Urea in mg/dL (“blood urea”) is common in India, Pakistan and parts of the Middle East and Asia. It is the weight of the whole urea molecule.
- BUN in mg/dL (blood urea nitrogen) is used in the United States and the Philippines. It counts only the nitrogen in urea, so the number is less than half the urea mg/dL value.
Always check whether your report says urea or BUN / urea nitrogen before converting.
Urea and BUN Conversion Factors
| Convert | Formula | Example |
|---|---|---|
| Urea mmol/L to urea mg/dL | mg/dL = mmol/L × 6.006 | 5 mmol/L = 30.0 mg/dL |
| Urea mg/dL to urea mmol/L | mmol/L = mg/dL ÷ 6.006 (or × 0.1665) | 40 mg/dL = 6.66 mmol/L |
| Urea mmol/L to BUN mg/dL | BUN = mmol/L × 2.8 | 7 mmol/L = 19.6 mg/dL BUN |
| BUN mg/dL to urea mmol/L | mmol/L = BUN ÷ 2.8 (or × 0.357) | 14 mg/dL BUN = 5.00 mmol/L |
| BUN mg/dL to urea mg/dL | urea = BUN × 2.14 | 20 mg/dL BUN = 42.9 mg/dL urea |
| Urea mg/dL to BUN mg/dL | BUN = urea ÷ 2.14 (or × 0.467) | 40 mg/dL urea = 18.7 mg/dL BUN |
Where the factors come from: urea weighs 60.06 g/mol, so 1 mmol/L = 6.006 mg/dL. Its two nitrogen atoms weigh 28.02 g/mol, so 1 mmol/L urea = 2.8 mg/dL BUN. The ratio between them, 60.06 ÷ 28.02 = 2.14, is the BUN to urea conversion factor.
How to Convert Urea to BUN (and BUN to Urea)
- Urea mmol/L to BUN mg/dL: multiply by 2.8. Urea 7 mmol/L × 2.8 = 19.6 mg/dL BUN.
- Urea mg/dL to BUN mg/dL: divide by 2.14. Urea 40 mg/dL ÷ 2.14 = 18.7 mg/dL BUN.
- BUN mg/dL to urea mg/dL: multiply by 2.14. BUN 15 mg/dL × 2.14 = 32.1 mg/dL urea.
- BUN mg/dL to urea mmol/L: divide by 2.8. BUN 20 mg/dL ÷ 2.8 = 7.14 mmol/L.
Urea Conversion Chart: mmol/L to mg/dL and BUN
| Urea (mmol/L) | Urea (mg/dL) | BUN (mg/dL) |
|---|---|---|
| 1.5 mmol/L | 9.0 mg/dL | 4.2 mg/dL |
| 2.0 mmol/L | 12.0 mg/dL | 5.6 mg/dL |
| 2.5 mmol/L | 15.0 mg/dL | 7.0 mg/dL |
| 3.0 mmol/L | 18.0 mg/dL | 8.4 mg/dL |
| 3.5 mmol/L | 21.0 mg/dL | 9.8 mg/dL |
| 4.0 mmol/L | 24.0 mg/dL | 11.2 mg/dL |
| 4.5 mmol/L | 27.0 mg/dL | 12.6 mg/dL |
| 5.0 mmol/L | 30.0 mg/dL | 14.0 mg/dL |
| 5.5 mmol/L | 33.0 mg/dL | 15.4 mg/dL |
| 6.0 mmol/L | 36.0 mg/dL | 16.8 mg/dL |
| 6.5 mmol/L | 39.0 mg/dL | 18.2 mg/dL |
| 7.0 mmol/L | 42.0 mg/dL | 19.6 mg/dL |
| 7.5 mmol/L | 45.0 mg/dL | 21.0 mg/dL |
| 8.0 mmol/L | 48.0 mg/dL | 22.4 mg/dL |
| 9.0 mmol/L | 54.1 mg/dL | 25.2 mg/dL |
| 9.4 mmol/L | 56.5 mg/dL | 26.3 mg/dL |
| 10.0 mmol/L | 60.1 mg/dL | 28.0 mg/dL |
| 12.0 mmol/L | 72.1 mg/dL | 33.6 mg/dL |
| 15.0 mmol/L | 90.1 mg/dL | 42.0 mg/dL |
| 20.0 mmol/L | 120.1 mg/dL | 56.0 mg/dL |
| 25.0 mmol/L | 150.2 mg/dL | 70.0 mg/dL |
| 30.0 mmol/L | 180.2 mg/dL | 84.0 mg/dL |
Urea mg/dL to mmol/L Conversion
If your report gives blood urea in mg/dL, divide by 6.006 to get mmol/L. The last column shows the equivalent BUN.
| Urea (mg/dL) | Urea (mmol/L) | BUN (mg/dL) |
|---|---|---|
| 10 mg/dL | 1.67 mmol/L | 4.7 mg/dL |
| 15 mg/dL | 2.50 mmol/L | 7.0 mg/dL |
| 20 mg/dL | 3.33 mmol/L | 9.3 mg/dL |
| 25 mg/dL | 4.16 mmol/L | 11.7 mg/dL |
| 30 mg/dL | 5.00 mmol/L | 14.0 mg/dL |
| 40 mg/dL | 6.66 mmol/L | 18.7 mg/dL |
| 45 mg/dL | 7.49 mmol/L | 21.0 mg/dL |
| 50 mg/dL | 8.33 mmol/L | 23.3 mg/dL |
| 60 mg/dL | 9.99 mmol/L | 28.0 mg/dL |
| 80 mg/dL | 13.32 mmol/L | 37.3 mg/dL |
| 100 mg/dL | 16.65 mmol/L | 46.7 mg/dL |
| 150 mg/dL | 24.98 mmol/L | 70.0 mg/dL |
BUN mg/dL to mmol/L Conversion
If your report gives BUN (urea nitrogen) in mg/dL, divide by 2.8 to get urea in mmol/L. The last column shows the equivalent urea in mg/dL.
| BUN (mg/dL) | Urea (mmol/L) | Urea (mg/dL) |
|---|---|---|
| 5 mg/dL | 1.79 mmol/L | 10.7 mg/dL |
| 7 mg/dL | 2.50 mmol/L | 15.0 mg/dL |
| 10 mg/dL | 3.57 mmol/L | 21.4 mg/dL |
| 14 mg/dL | 5.00 mmol/L | 30.0 mg/dL |
| 18 mg/dL | 6.43 mmol/L | 38.6 mg/dL |
| 20 mg/dL | 7.14 mmol/L | 42.9 mg/dL |
| 25 mg/dL | 8.93 mmol/L | 53.6 mg/dL |
| 30 mg/dL | 10.71 mmol/L | 64.3 mg/dL |
| 40 mg/dL | 14.29 mmol/L | 85.7 mg/dL |
| 50 mg/dL | 17.86 mmol/L | 107.2 mg/dL |
| 60 mg/dL | 21.43 mmol/L | 128.6 mg/dL |
| 80 mg/dL | 28.57 mmol/L | 171.5 mg/dL |
| 100 mg/dL | 35.71 mmol/L | 214.3 mg/dL |
Normal Urea and BUN Levels
| Test (adults) | mmol/L | mg/dL |
|---|---|---|
| Urea | about 2.5 – 7.8 | about 15 – 47 (as urea) |
| BUN (blood urea nitrogen) | about 2.5 – 7.1 (as urea) | about 7 – 20 (as BUN) |
Ranges vary between laboratories and are slightly higher in older adults. Urea rises with dehydration, a high-protein diet, bleeding in the gut and reduced kidney function, and falls with liver disease or low protein intake. Doctors usually interpret urea together with creatinine. Use the range printed on your own report and discuss results with your doctor.
Frequently Asked Questions
How do I convert urea from mmol/L to mg/dL?
Multiply by 6.006. For example, 5 mmol/L × 6.006 = 30.0 mg/dL urea.
What is urea 7 mmol/L in mg/dL?
Urea 7 mmol/L = 42.0 mg/dL as urea, or 19.6 mg/dL as BUN. It is within the usual adult reference range.
What is the BUN conversion factor?
BUN (mg/dL) ÷ 2.8 = urea (mmol/L), and urea (mmol/L) × 2.8 = BUN (mg/dL). The factor between BUN and urea in mg/dL is 2.14.
How do I calculate BUN from urea?
If urea is in mmol/L, multiply by 2.8. If urea is in mg/dL, divide by 2.14. Both give BUN in mg/dL.
How do I convert urea from mg/dL to mmol/L?
Divide by 6.006. For example, 40 mg/dL urea ÷ 6.006 = 6.66 mmol/L. If the value is BUN rather than urea, divide by 2.8 instead.
Is BUN the same as urea?
They measure the same substance but are expressed differently. BUN counts only the nitrogen part of urea, so BUN in mg/dL is about 47% of urea in mg/dL.
See all kidney function unit conversions for creatinine, uric acid and more.