Half-Life Calculator

The Half-Life Calculator applies the standard physics, chemistry, or engineering formula for half life and returns a numeric answer with the correct units. It's aimed at students, teachers, and working engineers who need a quick, dependable calculation without opening a full CAS.

Constants are taken from CODATA / NIST reference values and rounded to the precision most useful for classroom and applied work. If you need higher precision, the formula shown below the Half-Life Calculator lets you verify by hand.

• SI-first inputs with imperial options where they apply
• Answers labeled with units and, where useful, scientific notation
• Published formula visible on the page for verification
• No hidden assumptions — every input is exposed

Enter every value in the units listed next to each field. The Half-Life Calculator does not silently convert between systems mid-calculation, so mixed units produce a warning rather than a wrong answer.

For teaching, work through the formula shown under the results by hand, then confirm your answer against the Half-Life Calculator. This is a fast way to catch algebra mistakes without waiting on a marker.

The Half-Life Calculator uses double-precision floating-point math, which is accurate to about 15 significant figures — more than enough for undergraduate coursework and most engineering calculations involving half life.

Edge cases (division by zero, negative logarithms, out-of-range temperatures) are guarded, so the Half-Life Calculator surfaces a clear message rather than silently returning ±Infinity or NaN.