LDL cholesterol calculator
Estimate your LDL cholesterol from the three numbers a standard lipid panel gives you — total cholesterol, HDL, and triglycerides. This tool shows both the classic Friedewald estimate and the newer Sampson/NIH estimate (which stays accurate when triglycerides are high), in mg/dL or mmol/L.
Your privacy: this calculator runs entirely in your browser — nothing you type is sent anywhere. It's the same on-device principle Quanome is built on.
Educational reference only — not medical advice. Calculated LDL is an estimate; treatment decisions belong with a clinician, and there is no universal LDL target — the right level depends on your overall risk.
## What LDL numbers mean
| LDL cholesterol | Category |
| --- | --- |
| < 100 mg/dL (< 2.6 mmol/L) | Optimal |
| 100–129 mg/dL (2.6–3.3 mmol/L) | Near-optimal |
| 130–159 mg/dL (3.4–4.1 mmol/L) | Borderline-high |
| 160–189 mg/dL (4.1–4.9 mmol/L) | High |
| ≥ 190 mg/dL (≥ 4.9 mmol/L) | Very high |
These bands are a rough orientation, not a personal target. The LDL worth aiming for depends on your overall cardiovascular risk — see [what your LDL cholesterol level means](/blog/what-your-ldl-cholesterol-level-means/) for how that's judged.
## The equations
**Friedewald (1972)** — the classic, used by most labs:
- LDL = total cholesterol − HDL − (triglycerides ÷ 5) *(mg/dL; ÷ 2.2 for mmol/L)*
- Simple and accurate for typical results, but it **under-estimates LDL when triglycerides are high or LDL is low**, and it should not be used above ~400 mg/dL (4.5 mmol/L) of triglycerides.
**Sampson/NIH (2020)** — an expanded formula that stays accurate up to 800 mg/dL of triglycerides and at low LDL. This tool computes it alongside Friedewald so you can compare; when your triglycerides are above 400 mg/dL, only the Sampson estimate is shown, because Friedewald is no longer valid there.
**Martin/Hopkins** is a third modern method that swaps Friedewald's fixed “÷ 5” for an adjustable factor read from a lookup table. It needs that table to compute, so it isn't included here — but like Sampson it's more accurate than Friedewald at the extremes.
A **directly measured LDL** (a lab test rather than a calculation) is more accurate than any equation and is the fallback when triglycerides are very high.
## The rest of your lipid panel
LDL is one line on the panel, read alongside the others:
- **HDL** — the “good” cholesterol. See [what your HDL cholesterol level means](/blog/what-your-hdl-cholesterol-level-means/).
- **Triglycerides** — see [what high triglycerides mean](/blog/what-high-triglycerides-mean/).
- **Ratios** — the [total-cholesterol-to-HDL ratio](/blog/what-your-cholesterol-hdl-ratio-means/) puts the lines together; compute it with our [cholesterol ratio calculator](/tools/cholesterol-ratio-calculator/).
- Want to bring LDL down? See [how to lower LDL cholesterol](/blog/how-to-lower-ldl-cholesterol/).
Working in different units? Our [mmol/L ↔ mg/dL converter](/tools/mmol-mg-dl-converter/) switches any lipid result between the two.
## Track your lipids over time — privately
A single LDL is a snapshot; the value is in the **trend**. [Quanome](/) pulls your labs, Apple Health, and even your DNA into one private timeline on your device — parsed locally, never uploaded — with an AI coach that reads your lipid panel in whichever units you use.
Track your cholesterol over time, privately
Quanome unifies your labs, Apple Health, and DNA into one private, on-device timeline — in your units, with an AI coach. Free on the App Store and Google Play.
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