Osmolar Gap Calculator
Measured minus calculated serum osmolality.
About Osmolar Gap Calculator
Measured minus calculated serum osmolality. The Osmolar Gap Calculator on Picscaler gives you the answer instantly in your browser, with no sign-up.
Inputs: Measured osmolality (mOsm/kg), Sodium (mmol/L), Glucose (mg/dL) and BUN (mg/dL). Results shown: Calculated osmolality, Osmolar gap and Interpretation.
Formula: Calculated osmolality = 2 x Na + glucose/18 + BUN/2.8; gap = measured - calculated. A gap above about 10 mOsm/kg suggests unmeasured osmotically active substances. Read it with the clinical picture.
This tool is for education and information. It does not replace clinical judgement, so confirm results against your laboratory's reference ranges and local guidelines.
How to use Osmolar Gap Calculator
- Enter Measured osmolality (mOsm/kg), Sodium (mmol/L), Glucose (mg/dL) and BUN (mg/dL).
- Press Calculate.
- Read Calculated osmolality, Osmolar gap and Interpretation in the result table.
- Use the formula and notes under the result to check the working.
Frequently asked questions
Is Osmolar Gap Calculator free?
Yes. Osmolar Gap Calculator is completely free to use on Picscaler.
Do I need to create an account?
No. You can use it straight away without signing up.
Is my data safe?
Your input is processed in your browser on your own device and is not uploaded to Picscaler.
Can I use it for medical decisions?
No. It is an educational aid and does not replace professional medical judgement.
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