Half Life Calculator
Calculate radioactive decay and remaining amount
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How to Use Half Life Calculator
Enter initial amount
Enter starting quantity.
Enter half-life
Enter the half-life period.
Enter time
Enter elapsed time to see remaining amount.
Why Choose AllTools Half Life Calculator?
- ✓ Decay calculation
- ✓ Number of half-lives
- ✓ Percentage remaining
- ✓ Decay curve
- ✓ Any time unit
- ✓ No data stored
Why Use This Tool
- ★ All calculations happen locally in your browser
- ★ Completely free with no usage limits
- ★ No account or registration required
- ★ Based on established scientific formulas and constants
- ★ Works on any device with a modern browser
Related Resources
Frequently Asked Questions
What is half-life? ▼
The time for half of a radioactive substance to decay. After 1 half-life, 50% remains. After 2, 25% remains.
Can I use any time unit? ▼
Yes. You can use seconds, minutes, hours, days, or years. Just make sure the half-life and elapsed time use the same unit.
Does this work on mobile? ▼
Yes. All AllTools tools are fully responsive and work on phones and tablets.
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