What this calculator does
Corrected QT interval (QTc) works out heart-rate-adjusted QT interval from an ECG reading, using the Bazett and Fridericia formulas. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
The inputs explained
| Field | What to enter |
|---|---|
| Measured QT interval (ms) | A number, measured in ms. Starts at 400. |
| Heart rate (bpm) | A number, measured in bpm. Starts at 70. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with measured qt interval
Every other input is held at the calculator’s starting values while measured qt interval varies. Select any row to load that scenario into the calculator.