Half Life Calculator
Calculate remaining amount, percent decayed, decay constant and elapsed half-lives with exponential decay formulas.
Hit Calculate to see your decay curve
Calculate to solve for target time
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Your explanation appears here
Each half-life removes half of what remains, so decay slows in absolute amount as the sample gets smaller.
Your plan appears after calculation
Preview remaining amount at another elapsed time without changing your main result.
Calculate your baseline first
It uses N(t) = N₀ × (1/2)^(t / t½), where N₀ is the initial amount, t is elapsed time and t½ is the half-life. The calculation runs locally in your browser.
The decay constant is λ = ln(2) / half-life. It expresses the exponential decay rate per selected time unit, such as per day or per hour.
Yes, as long as half-life and elapsed time use the same unit. If the half-life is in days, enter elapsed time in days; if it is in years, enter elapsed time in years.
Results are estimates generated locally in your browser using standard exponential decay equations. They are for informational and educational purposes only. For laboratory safety, radiation handling, medicine dosing, environmental compliance or engineering decisions, use verified source data and qualified professional guidance. VisionVix accepts no liability for decisions based on this output.
