Radioactive Decay Calculator

Our Radioactive Decay Calculator helps you with radioactive decay problems. It makes nuclear physics calculations simple. This Radioactive Decay Calculator handles the complex math, letting you focus on understanding the science. This free tool enables you to find how much radioactive material remains after any amount of time.

How Radioactive Decay Calculator Works

Our calculator uses the radioactive decay formula:

A = A₀ × e^(-0.693t/T₁/₂)

Don’t worry about memorizing this! Just understand what each part means:

• A = Final activity (what we’re finding)
• A₀ = Starting activity (what you begin with)
• t = Time that passes
• T₁/₂ = Half-life of your isotope
• 0.693 = Natural logarithm of 2 (math constant)

Two Ways to Use Our Calculator

Here are the methods to use this calculator:

Method 1: Find Half-Life (Beta Feature)

Use this when you know the isotope name but need its half-life.

Steps:

1. Type your isotope name (like “Cobalt 60”)
2. Click “Calculate Half Life”
3. The calculator finds the half-life automatically
4. Use this half-life for Method 2

Method 2: Calculate Remaining Activity

Use this when you want to find how much remains after time passes.

You Need:

• Initial Activity (A₀): Starting amount
• Decay Time (t): How long you wait
• Half-Life (T₁/₂): From reference tables or Method 1

Step-by-Step Guide: Using the Calculator

Follow the given step to use this calculator in right way:

Step 1: Find Your Isotope’s Half-Life

Option A – Use Our Beta Feature:

• Enter isotope name (like “Carbon 14” or “Uranium 235”)
• Click “Calculate Half Life”

Option B – Look It Up:

• Check your textbook’s reference table
• Search online isotope databases
• Ask your teacher for the value

Step 2: Gather Your Information

You need three numbers:

• Starting activity (in any units: atoms, grams, becquerels, etc.)
• Time period (must match half-life units)
• Half-life (from Step 1)

Step 3: Check Your Units

This is super important! Make sure your time units match:

• If half-life is in years, use years for decay time
• If half-life is in days, use days for decay time
• If half-life is in seconds, use seconds for decay time

Step 4: Enter Values and Calculate

Put your numbers into the calculator and hit “Calculate” for instant results!

Real Example: Carbon-14 Dating

Let’s calculate how much carbon-14 remains in a 10,000-year-old fossil:

Given Information:

• Initial activity: 100 units (any unit works)
• Decay time: 10,000 years
• Carbon-14 half-life: 5,730 years

Using Our Calculator:

1. Initial Activity (A₀): 100
2. Decay Time (t): 10,000
3. Half-Life (T₁/₂): 5,730

Result: About 30.4 units remain

Check: After 10,000 years (almost 2 half-lives), we expect less than 25% to remain. Our answer makes sense!

Frequently Asked Questions