Corrected Sodium Calculator
The formula
What the corrected sodium tells you
Adds back the sodium dilution that hyperglycemia causes as glucose drags water out of cells — the number critical-care decisions actually use.
Calculation: Corrected Na = measured Na + factor × (glucose − 100)/100. Enter your inputs and every substitution is shown below the result.
Reading the result
In DKA the corrected sodium is the fluid-resuscitation guide: high corrected sodium means free-water deficit, low means real hyponatremia.
Rules of thumb: Classic 1.6 factor; Hillier’s 2.4 is physiologically better validated at extreme glucose
Limitations and best practice
Mannitol and glycine irrigant cause the same dilution without hyperglycemia; the glucose-correction formula misleads there.
This calculator gives an estimate based on standard formulas; it is not professional financial, medical, legal or engineering advice. Verify anything you plan to act on with a qualified professional and your own records.
Frequently asked questions
Does correction apply below normal glucose?
Is the corrected value a real lab result?
Source & methodology
Katz 1973; Hillier 1999.
Corrected Sodium explained: formula, worked example and honest limits
This page was written for one job: turning your own inputs into a defensible figure, with the working shown. Corrected Sodium is the kind of number people argue about from memory. This page ends that argument with arithmetic you can watch happen: enter your figures, get Corrected sodium in real time, and see every substitution printed below.
The useful way to hold Corrected Sodium is as a ratio with a story attached: Corrected Na = measured Na + factor × (glucose − 100)/100 says how the parts combine, and the 133.1 mEq/L figure above is simply that sentence written in numbers. Everything that follows unpacks one clause of the sentence at a time.
Trends beat snapshots. Corrected Sodium measured once tells you where you stand today; measured monthly against Measured sodium (mEq/L) tells you which way the needle is moving — and direction is the actionable information in Clinical Calculators.
What makes a calculation page trustworthy is that its copy is derived from its own arithmetic: here corrected sodium = 133.1 mEq/L, recomputed every time a field changes, and the sensitivity section ranks the inputs that move the result — Measured sodium first, at ≈9.5 % of the headline for a ten-percent error either way in that input — which is the thread the rest of this guide pulls on.
Every input in Corrected Sodium, and what it does to the answer
One formula, published in full: Corrected Na = measured Na + factor × (glucose − 100)/100. Anything you can read, you can reproduce in a spreadsheet, and that reproducibility is the whole point of printing it rather than hiding it behind a button.
Measured sodium (mEq/L) (example value 126) is a measured number in the unit named by the label; the formula does not convert for you. The example value is there to demonstrate the mechanics, not to describe your situation — overwrite it.
Serum glucose (mg/dL) (example value 397) is a measured number in the unit named by the label; the formula does not convert for you. Figures of this kind carry safety consequences; when in doubt, use the conservative value and confirm with a professional.
Correction factor (example value 2.4 (Hillier)) is a branching choice rather than a figure you measure; the per-option effects are computed below. The example value is there to demonstrate the mechanics, not to describe your situation — overwrite it.
What each “Correction factor” choice actually does: 1.6 (Katz) → 130.8 mEq/L · 2.4 (Hillier) → 133.1 mEq/L · 1.9 (average) → 131.6 mEq/L These figures are computed from this engine, not estimated — switch the dropdown above and you will land on exactly these numbers.
The default Corrected Sodium calculation, written out in full
Rather than describe the calculation, here it is end to end — every substitution in order, starting from the inputs above. Starting figures: Measured sodium (mEq/L), Serum glucose (mg/dL), Correction factor. Run to the end, the corrected sodium resolves to 133.1 mEq/L — At 397 mg/dL glucose the measured 126 is really 133 — hyperglycemic water shift dilutes sodium, and DKA protocols act on the corrected value on the bands this tool uses.
- Excess glucose = 397 − 100 = 297
- Correction = 2.4 × 2.97 = 7.1
- Corrected Na = 133.1 mEq/L
Dilutional drop — 7.1 mEq/L hidden. If your inputs change, this is usually the first companion figure to move.
True status — hidden hypernatremia risk. This is the number experienced users quote when the headline alone would mislead.
Factor used — 2.4 per 100 mg/dL. Read next to the headline, this is the figure that shows the shape of the trade-off.
Glucose over baseline — 297 mg/dL. Read next to the headline, this is the figure that shows the shape of the trade-off.
Re-running with your own figures is instant; re-running by hand once is the best way to know the tool is telling you the truth.
Scenario table: Corrected Sodium at ±10 % and ±20 % of the key input
Single-point answers invite false confidence, so the same engine was run across a band around the input that matters most here. Each row is a full recalculation of Corrected Sodium, not an interpolation.
| Measured sodium setting | Corrected sodium |
|---|---|
| 80 % of the example value | 107.9 mEq/L |
| 90 % of the example value | 120.5 mEq/L |
| example inputs | 133.1 mEq/L |
| 110 % of the example value | 145.7 mEq/L |
| 120 % of the example value | 158.3 mEq/L |
That spread — 107.9 mEq/L at the low end, 158.3 mEq/L at the high — is what a careful read of Corrected Sodium looks like: a band you can state out loud, with the reason for each edge. Reproduce it in the form above by editing Measured sodium alone; the substitution steps will follow your figures exactly.
What actually moves your Corrected Sodium
Nobody should have to guess which input matters. The engine was re-run once per field below — ten percent up, ten percent down, everything else frozen — and the results ranked by how far they moved the corrected sodium. Read it as a map of where Corrected Sodium is fragile — drawn for the example inputs, which is the map you want when deciding what to measure carefully.
- Measured sodium: ten percent up gives 145.7 mEq/L, ten percent down gives 120.5 mEq/L — ≈9.5 % of the corrected sodium either way
- Nudge Serum glucose by ±10 % and Corrected Sodium lands between 132.2 mEq/L and 134.1 mEq/L (sensitivity ≈0.7 %)
Measured sodium is the dominant lever here: ten percent either way moves the result by about 9.5 %, from 120.5 mEq/L to 145.7 mEq/L. Spend your verification effort there first, and treat Serum glucose as the second priority (≈0.7 % per ten percent). The remaining fields can sit at safe defaults without materially changing the answer — knowing which is which is what separates a careful calculation from an anxious one.
Is your Corrected Sodium good — reading the result bands
Nobody acts on a bare figure — they act on a figure with a comparison attached. The verdict attached to the default calculation — “At 397 mg/dL glucose the measured 126 is really 133 — hyperglycemic water shift dilutes sodium, and DKA protocols act on the corrected value” — is one band on a ladder your own figure may sit somewhere else on. The sensitivity list shows how far a modest input error moves you along that ladder: for Measured sodium, ±10 % covers 120.5 mEq/L to 145.7 mEq/L. The practical reading rules: ask what would have to change to move you one band. If the answer is “a small, plausible input difference”, the band itself is not the finding — the uncertainty is.
Placing this figure in context: calculators of this kind differ less in arithmetic than in what they choose to ignore. This one keeps Measured sodium (mEq/L) explicit so that the omissions are visible rather than hidden in a preset.
Common mistakes with Corrected Sodium (and the fix)
Mannitol and glycine irrigant cause the same dilution without hyperglycemia; the glucose-correction formula misleads there. This calculator gives an estimate based on standard formulas; it is not professional financial, medical, legal or engineering advice. Verify anything you plan to act on with a qualified professional and your own records.
Mixing units between tools. Metric and imperial entry paths round differently — keep one system top to bottom.
Attention is also misallocated between fields. Having measured this engine, we can say where it belongs: Measured sodium first, everything else second.
Another is comparing across contexts: a Corrected Sodium computed with one set of conventions should never be lined up against a figure computed with another. Check the inputs behind both before ranking them.
Six things to confirm before acting on Corrected Sodium
- Confirm the example values are plausible for your own situation before replacing them.
- Record the date and the inputs alongside the number so future-you knows what was assumed.
- Re-verify Measured sodium against a source document — ten percent of error there moves the headline by ≈9.5 %.
- Recompute once with the dominant input deliberately set low, and see whether the decision changes.
- Note the date and the inputs beside the number so the figure can be audited later.
- Repeat the ±10 % test on the inputs that matter and see whether the decision — not just the number — still holds.
How to use the Corrected Sodium tool properly
The tool does the arithmetic; the routine below is what makes the arithmetic trustworthy. Five steps, a minute total — and afterwards you will know not just what the number is, but which assumption produced it.
Step 1 — collect, then type. Everything this tool asks for is listed above (measured sodium (meq/l), serum glucose (mg/dl), correction factor). Pull each figure from something you can point at — paperwork, a dashboard, a label — before touching a field. Guesswork at the input stage cannot be repaired at the interpretation stage. Re-running a number costs seconds; retracting a decision costs considerably more.
Step 2 — start from the case you can defend. Enter pessimistic-but-honest figures first; the optimistic run is a ceiling, not a plan. A conclusion that holds on conservative inputs holds everywhere. When in doubt, prefer the boring input: the interesting one is usually the one you misread.
Step 3 — play with the inputs on purpose. Ten percent up, ten percent down, one field at a time. Within a few minutes you will know this calculation better than most people who quote its results. Comparisons are cheap: run the identical calculation for the alternative and look at the gap.
Step 4 — ask what would have to be true. Take the result you want and work backwards through the inputs until you find the assumption that produces it; then decide honestly whether that assumption is defensible. Re-running a number costs seconds; retracting a decision costs considerably more.
Step 5 — write the one-line memo. “Corrected sodium = 133.1 mEq/L on this date, from these inputs.” That line is the entire deliverable; everything else on this page is how you earned the right to write it. A calculation you cannot explain to somebody else is a calculation you cannot defend.
From calculation to decision: where Corrected Sodium earns its keep
Most Clinical Calculators disagreements are arithmetic disagreements in disguise. When Corrected sodium of 133.1 mEq/L sits on the table with its working shown, the conversation stops being about who sounds more confident and starts being about which input is wrong. Comparisons are cheap: run the identical calculation for the alternative and look at the gap.
The audience for this page is people who need one trustworthy number before their next decision. In professional Clinical Calculators practice the pattern is always the same — screen with Corrected Sodium, then invest slow analysis only in whatever survives the screen. If a result feels obviously right, that is the moment to check the inputs hardest.
Nothing here is stored or transmitted, so the habit of checking is free: open the page, re-enter current figures, compare with the number you saved last time. Rounding early is the quietest way to introduce a permanent error.
Corrected Sodium — frequently asked questions
What affects Corrected Sodium the most?
Measured on this engine, Measured sodium is the dominant lever: moving it ±10 % shifts the corrected sodium across 120.5 mEq/L to 145.7 mEq/L — about 9.5 % of the headline, with Serum glucose next at ≈0.7 %. The ranked list in the sensitivity section is computed live, not asserted from a template.
Which matters more: serum glucose or measured sodium?
Measured sodium, by a factor of about 13.2. Concretely: ten percent on Measured sodium is worth ≈9.5 % of Corrected Sodium, the same nudge on Serum glucose only ≈0.7 %. That ranking is re-computed for each page from that page’s own defaults.
How much does the “Correction factor” choice change the answer?
A great deal, on these inputs: Corrected Sodium comes out at 130.8 mEq/L on the lowest option (“1.6 (Katz)”) and 133.1 mEq/L on the highest (“2.4 (Hillier)”). Each option is listed with its computed value so you can see what the choice is worth before you make it.
What is a typical Corrected Sodium?
On the worked example above Corrected Sodium comes out at 133.1 mEq/L. Treat that as one point on a distribution rather than a norm: the bands, the companion outputs and the sensitivity ranking tell you how wide the plausible range really is.
How do I calculate Corrected Sodium by hand?
Three steps: write the formula (Corrected Na = measured Na + factor × (glucose − 100)/100), insert your values, and simplify. The worked example section shows exactly that chain for the default inputs; replicating it once on paper teaches you more about Corrected Sodium than any number of calculator runs.
What happens to Corrected Sodium if measured sodium changes by 10 %?
The engine was re-run with that field moved by ten percent while everything else stayed fixed: the corrected sodium goes across 120.5 mEq/L to 145.7 mEq/L, a swing of roughly 9.5 % around the 133.1 mEq/L baseline. That ratio is the practical definition of how much this input matters.
Is the Corrected Sodium result of 133.1 mEq/L good or bad?
The tool answers “what”, not “whether”: 133.1 mEq/L carries the verdict “At 397 mg/dL glucose the measured 126 is really 133 — hyperglycemic water shift dilutes sodium, and DKA protocols act on the corrected value” for the default case, which is a starting interpretation rather than a verdict on your situation. Re-run with your own figures and compare the bands.
Does Corrected Sodium change with age?
Yes — reference bands shift deliberately across the lifespan, which is why this tool prints an interpretation rather than a bare number. Re-read the bands each time inputs like Measured sodium (mEq/L) change materially.
Is Corrected Sodium accurate?
The arithmetic is exact: Corrected Na = measured Na + factor × (glucose − 100)/100 is evaluated with full floating-point precision and every substitution is printed in the worked example. What limits accuracy is input quality and the model’s assumptions, so treat the 133.1 mEq/L result as the correct answer to the question you typed — and check the assumptions section before acting on it.
Does correction apply below normal glucose?
No — the shift is one-directional; hypoglycemia does not concentrate sodium meaningfully.
Is the corrected value a real lab result?
No, it is a derived estimate — treat it as a decision aid, not a measurement.
Does this Corrected Sodium tool store my numbers?
No. The entire calculation runs in your browser session; nothing entered above is transmitted or saved, which is the correct behaviour for sensitive Health & Medical figures and the reason you can re-run this page as often as you like.
Key terms on this page
- Dilutional drop
- 7.1 mEq/L hidden on the example inputs — a companion figure printed beside the headline of Corrected Sodium so that no result is read in isolation.
- True status
- hidden hypernatremia risk in the default Corrected Sodium calculation — one of the secondary figures an experienced reader checks before trusting the primary number.
- Factor used
- 2.4 per 100 mg/dL on the example inputs — a companion figure printed beside the headline of Corrected Sodium so that no result is read in isolation.
- Corrected sodium
- The primary output of this tool: 133.1 mEq/L for the default inputs, computed exactly from Corrected Na = measured Na + factor × (glucose − 100)/100.
- Worked example
- The step-by-step substitution printed above, so the arithmetic can be re-derived by hand or in a spreadsheet.
- Verdict band
- The plain-language label — here “At 397 mg/dL glucose the measured 126 is really 133 — hyperglycemic water shift dilutes sodium, and DKA protocols act on the corrected value” — mapping the computed figure onto experience-based ranges for Health & Medical.
- Sensitivity (±10 %)
- How far the Corrected Sodium moves when a single input is nudged ten percent either way; the ranked list on this page is computed live from this engine.
Method, sources and what this tool cannot tell you
There is no black box on this page — the engine evaluates Corrected Na = measured Na + factor × (glucose − 100)/100. Source of record: Katz 1973; Hillier 1999. Where a professional version of this calculation differs, it differs in inputs and jurisdiction-specific coefficients, not in the algebra — which is why re-checking your inputs beats hunting for a second calculator.
This page is an estimation aid, not professional advice. The design rule is simple: two people entering identical figures must get identical answers. Nothing is smoothed, weighted or adjusted behind the scenes; where judgement enters, this page says so and names the input responsible.
Next steps after the calculation
Save the number together with its inputs and today’s date; a Corrected Sodium figure without context is unusable the moment an input changes.
The audience here is people who need one trustworthy number before their next decision. Everything you need to defend the result — formula, substitution, sensitivity, source — is printed above, so the only remaining variable is the honesty of your inputs.