Radiation Converter

Convert absorbed dose and equivalent or effective dose between all common radiation units.

Covers absorbed (mGy, µGy, cGy, rad, Gy) and equivalent/effective (µSv, mSv, mrem, Sv, rem, BED) units.

Updated August 21, 2026

CreatorFrank Zhao

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Overview

The Radiation Converter is a bidirectional unit converter for two distinct quantities that are often mixed up: absorbed dose (energy deposited per kilogram, in grays) and equivalent / effective dose (biologically weighted dose, in sieverts). It also handles the informal banana equivalent dose (BED) so you can sanity-check headlines without guessing.

Who it helps

Students and lab staff converting between the SI units (Gy, Sv) and the older CGS units (rad, rem) that still appear in textbooks and instruments.
Anyone reading dose reports — imaging referrals, airport scanner briefings, environmental monitoring — who needs to compare µSv, mSv, and mrem accurately.
Communicators and curious readers who encounter “bananas worth of radiation” and want the real number behind the analogy.

Not a medical tool. This converter only changes the unit — it does not weight dose by radiation type or organ sensitivity, and it does not assess health risk. For anything beyond arithmetic, follow the guidance where it appears or consult a qualified professional.

How to use

The two dose groups are independent. Editing a value in the Absorbed dose card only re-derives the other two fields in that card; the Equivalent / effective dose card stays untouched, and vice versa. Any field can be the input — the engine picks the correct derivation automatically.

Pick the right card

Use Absorbed dose when the source reports Gy, mGy, µGy, cGy, or rad. Use Equivalent / effective dose when it reports Sv, mSv, µSv, mrem, rem, or BED.

Type in any field and choose its unit

Each field has its own unit switcher. For example, “Dose in grays” defaults to Gy but can show the same value in mGy, µGy, cGy, or rad.

Read the other two fields

They update instantly. Switch any unit afterwards to keep the same physical dose with a different display. Clear a field to reset that card.

Quick walkthrough — 0.1 mSv chest X-ray

Say you want to see a typical chest X-ray effective dose of $0.1\ \mathrm{mSv}$ in the other units.

0.1\ \mathrm{mSv}

=

100\ \mu\mathrm{Sv}

=

0.01\ \mathrm{rem}

=

10\ \mathrm{mrem}

=

1000\ \mathrm{BED}

Type $0.1$ in “Dose in millisieverts” (mSv). The converter fills microsieverts and rem automatically; switch any field to BED to see the ≈ 1,000-banana figure.

Formulas & units

All six fields are pure unit conversions — there is no cross-conversion between absorbed dose (Gy family) and equivalent dose (Sv family) because that requires a radiation weighting factor and, for effective dose, a tissue weighting factor.

Absorbed dose (base mGy)

D_{\mathrm{target}}

=

D_{\mathrm{source}}\times \dfrac{f_{\mathrm{source}}}{f_{\mathrm{target}}}

$f$ is the factor to milligrays: 1 mGy = 1, 1 µGy = 0.001, 1 cGy = 10, 1 rad = 10, 1 Gy = 1000. So 1 Gy = 100 rad.

Equivalent / effective dose (base mSv)

H_{\mathrm{target}}

=

H_{\mathrm{source}}\times \dfrac{f_{\mathrm{source}}}{f_{\mathrm{target}}}

$f$ is the factor to millisieverts: 1 mSv = 1, 1 µSv = 0.001, 1 mrem = 0.01, 1 rem = 10, 1 Sv = 1000, 1 BED ≈ 0.0001.

Reference table — exact factors used

Display unit	To base	Example
$\mu\mathrm{Gy}$ / µGy	$\times 0.001$ mGy	1000 µGy = 1 mGy
cGy / rad	$\times 10$ mGy	1 cGy = 1 rad = 10 mGy
Gy	$\times 1000$ mGy	0.5 Gy = 500 mGy = 50 rad
$\mu\mathrm{Sv}$ / µSv	$\times 0.001$ mSv	1000 µSv = 1 mSv
mrem / rem	$\times 0.01$ / $\times 10$ mSv	1 rem = 10 mSv = 1000 mrem
BED 🍌	$\times 0.0001$ mSv	1 mSv ≈ 10,000 BED

BED is an informal communication aid. The converter uses the common convention of about $0.1\ \mu\mathrm{Sv}$ per banana (≈ 0.0001 mSv), consistently in both directions. Different sources quote slightly different values; treat the BED number as illustrative.

Worked examples

A — Radiotherapy fraction in grays

A treatment note says $2\ \mathrm{Gy}$ to the target. What is that in mGy, cGy, µGy, and rad?

2\ \mathrm{Gy}

=

2000\ \mathrm{mGy}

=

200\ \mathrm{cGy}

=

200\ \mathrm{rad}

2\ \mathrm{Gy}

=

2\,000\,000\ \mu\mathrm{Gy}

Enter $2$ in “Dose in grays” (Gy). Switch any field to µGy to see 2,000,000 µGy — same physical dose, different scale.

B — Environmental report in mrem

An environmental summary reports $25\ \mathrm{mrem}$ per year. How does that read in µSv, mSv, rem, and bananas?

25\ \mathrm{mrem}

=

0.25\ \mathrm{mSv}

=

250\ \mu\mathrm{Sv}

=

0.025\ \mathrm{rem}

0.25\ \mathrm{mSv}

=

2500\ \mathrm{BED}

Type $25$ in any equivalent-dose field set to mrem, then switch one field to µSv or BED to compare. Remember, BED is only an informal scale.

Tips & pitfalls

Don’t cross the two cards

Gy/rad/mGy and Sv/rem/mSv look similar but mean different things. A gray measures deposited energy; a sievert adds biology. The converter keeps them separate on purpose.

Watch the µ prefix

One mistyped “m” for “µ” is a factor of 1,000. Before copying into a report, confirm whether the source says mGy/µGy or mSv/µSv.

Treat BED as an analogy

Bananas vary in potassium content and no one is “dosed” by eating them in the sense the sievert measures. Use BED only to illustrate scale, not to argue about risk.

Keep units with the number

When you paste results elsewhere, include the unit (e.g., “0.25 mSv” not “0.25”). That prevents the most common hand-off error.

Related concepts

Absorbed dose vs. equivalent dose

Absorbed dose ( $D$ in grays) is purely physical. Equivalent dose ( $H_T$ in sieverts) multiplies absorbed dose by a radiation weighting factor $w_R$ to reflect how effectively a given radiation type causes biological effect. Effective dose adds a further tissue weighting ( $w_T$ ). This converter does not apply those factors — it only re-expresses a dose you already have in a different unit.

SI vs. CGS: Gy/Sv and rad/rem

$1\ \mathrm{Gy}=100\ \mathrm{rad}$ and $1\ \mathrm{Sv}=100\ \mathrm{rem}$ . Modern work uses grays and sieverts, but older U.S. sources often use rad and rem. Keep an eye on which family a value belongs to.

What’s next?

If your source reports activity (becquerels, curies) or exposure (roentgens) rather than dose, you need a different conversion that accounts for isotope, geometry, and shielding.

Length Converter

Continue converting between metric and imperial units.

Weight Converter

Convert mass units for related measurements.

Frequently Asked Questions

Can I convert grays directly to sieverts?

Not by a single fixed factor. A sievert is a gray multiplied by a radiation weighting factor (and, for effective dose, summed with tissue weightings). For some contexts — e.g., 250 keV photons where $w_R=1$ — the numbers coincide, but that is a special case, not a general conversion. Use this converter only to change the unit within the same quantity.

How reliable is the banana unit?

About $0.1\ \mu\mathrm{Sv}\approx 0.0001\ \mathrm{mSv}$ per banana is the common informal reference this calculator uses. Real bananas differ slightly, and potassium in food is not a dose in the regulatory sense. Treat the BED as a communication shortcut.

Why does 1 Gy equal 100 rad?

The rad is the CGS counterpart of the gray: 1 rad = 0.01 Gy by definition, so 1 Gy = 100 rad. The same 100:1 ratio holds for the sievert/rem pair.

Limitations & Disclaimers

•This is a unit converter only. It does not convert between absorbed dose and equivalent/effective dose, and it does not estimate health risk.
•Inputs must be non-negative numbers. Negative doses are rejected because a dose is a physical energy or weighted quantity.
•Banana equivalent doses use an informal, approximate reference ( $0.1\ \mu\mathrm{Sv}$ per BED) and are intended for illustration, not decision-making.
•For medical, occupational, or regulatory questions, rely on the official report and qualified guidance rather than on a unit conversion alone.

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