Banana Radiation Calculator

☢ What is the Banana Equivalent Dose (BED)?

The Banana Equivalent Dose (BED) is an informal measurement of ionizing radiation exposure, using the radiation from eating one average banana as a baseline. One BED equals approximately 0.1 microsieverts (0.1 µSv).

Bananas are naturally radioactive because they contain potassium, and about 0.0117% of natural potassium is the radioactive isotope potassium-40 (K-40). An average banana contains roughly 450 mg of potassium, resulting in about 15 becquerels of radioactivity.

The BED concept was introduced as a way to communicate radiation risk to the general public by comparing abstract dose numbers to something familiar and unthreatening. It was popularized in radiation safety education and is widely used in physics classrooms and science communication.

📊 Common Radiation Doses Reference

🧪 The Science Behind Banana Radiation

Potassium-40 is a naturally occurring radioactive isotope with a half-life of 1.25 billion years. It decays through three pathways: beta-minus emission (89.3%), electron capture (10.5%), and beta-plus emission (0.2%).

When you eat a banana, the K-40 delivers about 0.1 µSv of radiation. However, your body maintains potassium homeostasis — meaning if you eat an extra banana, your kidneys simply excrete the excess potassium. You cannot meaningfully increase your internal radiation dose by eating more bananas.

This is why the BED is best used for comparisons and communication, not precise dosimetry. The dose from a banana is real, but the biological impact is essentially zero because your body's potassium level stays constant regardless of dietary intake.

📐 How to Use This Calculator

1. Enter a radiation dose — type a number in the dose field, or select a common radiation source from the preset dropdown.
2. Select the unit — choose from microsieverts (µSv), millisieverts (mSv), sieverts (Sv), millirem (mrem), or rem.
3. Click Calculate — the tool instantly converts your dose to Banana Equivalent Doses and shows unit conversions, a risk level indicator, a comparison chart, and a visual banana pile.

❓ Frequently Asked Questions