Work out your cholesterol ratio from a lipid test
This cholesterol ratio calculator takes the numbers from a cholesterol (lipid) blood test and works out the total cholesterol to HDL ratio — the figure UK and New Zealand reports often show as “TC:HDL” or “cholesterol ratio” — plus the LDL to HDL ratio, the triglyceride to HDL ratio and non-HDL cholesterol.
Type your results in mg/dL (US, India) or mmol/L (UK, Europe, Australia, New Zealand); switching units converts them for you. Your numbers are also compared with the NHS healthy levels.
It is information only and not a diagnosis. Cholesterol is judged together with blood pressure, smoking, diabetes, age and family history.
How to use the cholesterol ratio calculator
- Choose the units on your report and your sex (used only for the HDL guide).
- Enter total cholesterol and HDL cholesterol.
- Add LDL and triglycerides if your report has them; if LDL is missing but triglycerides are there, LDL is estimated for you.
- Read the ratio, the other ratios and non-HDL, and the comparison table; copy the result for your notes.
Cholesterol Ratio Calculator features
All the common ratios
Total/HDL, LDL/HDL and triglyceride/HDL, with non-HDL cholesterol and HDL as a share of total.
mg/dL or mmol/L
Converts as you switch and shows the triglyceride/HDL ratio in both units, because it differs.
UK guide values
NHS healthy levels for total, HDL and non-HDL, and the Heart UK note on the ratio.
LDL estimate
Friedewald’s equation fills in LDL when your report leaves it out.
How the ratios are calculated
The cholesterol ratio is total cholesterol divided by HDL. Because both are cholesterol, the ratio is the same in mg/dL and mmol/L: 200 ÷ 50 mg/dL = 5.17 ÷ 1.29 mmol/L = 4.0. LDL/HDL works the same way: 130 ÷ 50 = 2.6.
The triglyceride/HDL ratio is different, because triglycerides and cholesterol convert with different factors (88.57 and 38.67). A ratio of 3.0 in mg/dL equals about 1.3 in mmol/L, so always check which units a quoted value uses. Non-HDL cholesterol is simply total minus HDL.
If LDL is blank and triglycerides are under 400 mg/dL (4.5 mmol/L), LDL is estimated with the Friedewald equation: TC − HDL − TG ÷ 5 in mg/dL, or TG ÷ 2.2 in mmol/L. The LDL calculator also gives the newer Martin/Hopkins and Sampson estimates.
Guide values (checked 24 October 2026)
| Measure | Guide | Source |
|---|---|---|
| Total cholesterol | below 5 mmol/L (193 mg/dL) | NHS, reviewed 13 Mar 2026 |
| HDL cholesterol | above 1.0 mmol/L (39 mg/dL) men; above 1.2 mmol/L (46 mg/dL) women | NHS |
| Non-HDL cholesterol | below 4 mmol/L (155 mg/dL) | NHS |
| Total/HDL ratio | above 6 is considered high risk; lower is better | Heart UK |
| Triglyceride/HDL ratio | no guideline cut-off | — |
Reading your result
- A lower total/HDL ratio is better. It can improve by lowering LDL or by raising HDL.
- In the UK the ratio feeds into QRISK3, the 10-year risk score GPs use; in the US, risk is usually estimated with the ASCVD risk calculator. For an overall picture, try the heart age calculator.
- Results vary from test to test and with fasting, illness and some medicines, so one result is rarely the whole story.
- To convert a single value between units, use the mg/dL to mmol/L converter.
Cholesterol Ratio Calculator FAQ
What is a good cholesterol ratio?
Lower is better. Heart UK describes a total/HDL ratio above 6 as high risk; many people aim well below that, but your doctor will judge it with your other risk factors.
How do I calculate my cholesterol ratio?
Divide total cholesterol by HDL cholesterol, using the same units for both. The cholesterol ratio calculator above does this and the other ratios for you.
Is the cholesterol ratio the same in mmol/L and mg/dL?
Yes for total/HDL and LDL/HDL. The triglyceride/HDL ratio is not — divide a mg/dL ratio by about 2.29 to get the mmol/L ratio.
What does the cholesterol ratio on a UK or NZ report mean?
It is usually “TC:HDL”, total cholesterol divided by HDL. It is used alongside other factors in cardiovascular risk scores.
What is non-HDL cholesterol?
Total cholesterol minus HDL: all the cholesterol carried in particles that can build up in arteries. The NHS healthy level is below 4 mmol/L.
Is this cholesterol ratio calculator medical advice?
No. It is for information only. Discuss your results with your doctor.