Enter the natural logarithm of 2 and the decay constant into the calculator to determine the Halfing Time or Half-life. This calculator can also evaluate any of the variables given the others are known.

## Halfing Time Formula

The following formula is used to calculate the Halfing Time or Half-life.

T = ln(2) / λ

Variables:

- T is the Halfing Time or Half-life (time units)
- λ is the decay constant (1/time units)

To calculate the Halfing Time or Half-life, take the natural logarithm of 2 and divide it by the decay constant. The decay constant is a measure of the rate at which the quantity is decaying. The higher the decay constant, the faster the quantity decays and the shorter the Halfing Time or Half-life.

## What is a Halfing Time?

Halfing Time, also known as half-life, is a term commonly used in nuclear physics and chemistry to describe the time required for a quantity to reduce to half of its initial value. The term is commonly used in relation to radioactive decay, where it represents the time it takes for half of the radioactive atoms in a sample to decay, but it can also be used to describe any quantity that follows an exponential decay, such as the decay of pharmaceutical drugs in the body.

## How to Calculate Halfing Time?

The following steps outline how to calculate the Halfing Time using the formula T = ln(2) / λ.

- First, determine the decay constant (λ) in units of 1/time.
- Next, use the formula T = ln(2) / λ to calculate the Halfing Time (T) in time units.
- Finally, check your answer with the calculator above.

**Example Problem:**

Use the following variables as an example problem to test your knowledge.

decay constant (λ) = 0.05 1/time