Radiation dose calculator
An absorbed dose of 0.002 Gy to the lung from photons, with weighting factors of 1 and 0.12, gives an effective dose of 0.00024 Sv. Enter the dose in grays and both weighting factors to get sieverts. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Absorbed dose
- 0.002
- Radiation weighting factor
- 1
- Tissue weighting factor
- 0.12
- Equivalent dose
- 0.002 Sv
- Effective dose
- 0.00024
Effective radiation dose is the ICRP protection quantity that folds absorbed dose in grays together with a radiation weighting factor and a tissue weighting factor so the result can be expressed in sieverts. Radiographers, health-physics students, and safety officers use that product when a measured or estimated organ absorbed dose must be compared on a common scale across photon, neutron, or alpha exposures and across tissues that do not share the same stochastic risk. This calculator implements the closed form exactly: effective dose E equals absorbed dose D times w_R times w_T, and equivalent dose H equals D times w_R. You supply a nonnegative absorbed dose in grays plus the two dimensionless weighting factors. Zero absorbed dose is allowed and yields zero sieverts.
How effective dose is defined and why weighting factors exist
Absorbed dose D is the mean energy imparted by ionizing radiation per unit mass of tissue, expressed in grays, where one gray equals one joule per kilogram. Two exposures that deposit the same energy per kilogram are not always equivalent in radiation protection, because densely ionizing particles such as alpha fragments produce more biological damage per gray than photons or electrons, and because some organs carry a larger share of stochastic risk than others.
The International Commission on Radiological Protection therefore multiplies absorbed dose by a radiation weighting factor w_R to obtain equivalent dose H in sieverts, then multiplies that organ equivalent dose by a tissue weighting factor w_T to obtain the contribution to effective dose E. For a single organ and a single radiation quality the closed form is E equals D times w_R times w_T, with E and H both in sieverts when D is in grays.
Typical ICRP Publication 103 values of w_R are one for photons, electrons, and muons, two for protons and charged pions, and twenty for alpha particles, fission fragments, and heavy ions; neutron weighting is energy dependent and must be supplied as a number, not guessed.
Typical w_T values include zero point twelve for lung, colon, stomach, bone marrow, breast, and remainder, zero point zero eight for gonads, zero point zero four for bladder, liver, oesophagus, and thyroid, and zero point zero one for bone surface, brain, salivary glands, and skin; whole-body effective dose uses w_T equals one when the absorbed dose already represents a whole-body mean.
This calculator does not look those tables up for you: you enter the factors that match the radiation quality and the organ of interest so the arithmetic stays transparent and auditable. A negative absorbed dose is not a physical energy deposit and is rejected. Zero absorbed dose is allowed and yields zero sieverts.
Always frame outputs as educational estimates from the published product, not as a personal dosimeter reading, a regulatory report, or a substitute for a qualified medical physicist.
Where an effective-dose calculator shows up in real work
Radiography and nuclear-medicine courses constantly assign organ-dose drills from textbook gray and weighting-factor triples, so a single trusted oracle that returns sieverts beside the raw absorbed dose speeds grading and demo setup. Health-physics and radiation-protection programs introduce ICRP equivalent and effective dose before students meet a full Monte Carlo phantom, and instructors need deterministic answer keys that match hand arithmetic with an explicit w_R and w_T.
Product teams building educational clinical calculators want a documented gray-to-sievert path that clients can audit by hand rather than a black-box organ-dose engine that mixes conversion coefficients, scan protocols, or phantom libraries without disclosure. Research assistants preparing synthetic dosimetry datasets need stable effective-dose labels from known D, w_R, and w_T pairs without network calls or model drift.
If you later need gray-to-rad conversion, sievert-to-rem conversion, linear energy transfer units, or a cosmic-dose estimate from flight hours, treat those as separate search intents and landings rather than overloading this radiation dose calculator page. Always present results as educational estimates from the classical ICRP product; clinical or occupational decisions require qualified professionals, calibrated instruments, and protocols this tool does not collect.
Pin the rounded sievert value in tests, keep requests small, and you get reproducible effective doses for homework, LMS plugins, and edge workers without standing up a medical-device stack of your own.
What you can do with it
Classroom ICRP effective-dose answer keys
Generate sieverts from textbook absorbed-dose and weighting-factor triples so instructors and auto-graders share one transparent ground truth.
Photon versus alpha teaching demos
Show how the same gray yield a twenty-fold larger equivalent dose when w_R changes from photons to alpha particles, without mixing unit converters on this landing.
FAQ
What is effective radiation dose?
Effective dose E is absorbed dose in grays multiplied by the radiation weighting factor w_R and the tissue weighting factor w_T. The result is in sieverts and places an organ exposure on a common protection scale.
What formula do you use?
Equivalent dose H = D × w_R and effective dose E = D × w_R × w_T, with D in grays. Both H and E are returned in sieverts. You supply w_R and w_T; the calculator does not look up ICRP tables from a radiation type or organ name.
What happens if absorbed dose is negative?
Absorbed dose is energy per kilogram and cannot be negative; the engine rejects the value rather than returning a signed sievert figure.
Can absorbed dose be zero? What typical weighting factors should I enter?
Zero absorbed dose is allowed and yields 0 Sv. Typical ICRP 103 w_R values are 1 (photons), 2 (protons), and 20 (alpha). Typical w_T values include 0.12 for lung and 1 for a whole-body mean. Negative weighting factors fail.
What does the radiation dose calculator cost?
The browser tool is free and runs locally.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/health/radiation-dose \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"absorbed_dose":0.002,"radiation_weighting_factor":1,"tissue_weighting_factor":0.12}'const res = await fetch("https://api.kit.forhosting.com/health/radiation-dose", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"absorbed_dose": 0.002,
"radiation_weighting_factor": 1,
"tissue_weighting_factor": 0.12
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/health/radiation-dose",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"absorbed_dose": 0.002,
"radiation_weighting_factor": 1,
"tissue_weighting_factor": 0.12
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/health/radiation-dose", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"absorbed_dose":0.002,"radiation_weighting_factor":1,"tissue_weighting_factor":0.12}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"absorbed_dose":0.002,"radiation_weighting_factor":1,"tissue_weighting_factor":0.12}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/health/radiation-dose", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"absorbed_dose": 0.002,
"radiation_weighting_factor": 1,
"tissue_weighting_factor": 0.12
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "health.radiation_dose",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
A negative absorbed dose is rejected with invalid_input instead of inventing a signed sievert value.
How effective dose is defined and why weighting factors exist
The arithmetic is pure floating-point with stable rounding to twelve significant digits, no network calls, no random seeds, and no wall-clock timestamps, so identical triples always serialize to the same JSON.
What you send, what you get back, and how errors behave
Send three required fields. A negative radiation or tissue weighting factor also fails because ICRP weighting is not defined with a minus sign. If your upstream form collects milligray, rad, or rem, convert to gray and sievert-consistent weighting first and pass the numbers here. The field absorbed_dose is the absorbed dose D in grays and must be a finite nonnegative number; zero is allowed and negative values fail. Aliases D, dose, dose_gy, gy, and absorbed are accepted. The field radiation_weighting_factor is the dimensionless ICRP w_R and must be a finite nonnegative number; aliases w_r, wr, wR, and radiation_wf are accepted. The field tissue_weighting_factor is the dimensionless ICRP w_T and must be a finite nonnegative number; aliases w_t, wt, wT, and tissue_wf are accepted. Missing required fields, empty strings, non-numeric values, NaN, and Infinity fail with invalid_input and are not charged. On success the response echoes the cleaned absorbed_dose, radiation_weighting_factor, and tissue_weighting_factor, returns equivalent_dose as D times w_R, returns effective_dose as D times w_R times w_T, sets unit to Sv, restates the formula string E equals D times w_R times w_T, and sets method to icrp_effective_dose. Classic smoke checks include two milligray of photons in lung tissue, which is absorbed_dose zero point zero zero two with w_R one and w_T zero point twelve and yields effective_dose zero point zero zero zero two four sieverts, and ten milligray of alpha particles to the whole body, which is absorbed_dose zero point zero one with w_R twenty and w_T one and yields effective_dose zero point two sieverts. Pricing for successful API calls is the published base of $0.002 per item; validation failures do not consume prepaid balance.
Where an effective-dose calculator shows up in real work
Because this capability is a pure parse engine, API pricing is the published base of $0.002 per successful item and failed validation does not consume balance.
Integration use cases
Deterministic dosimetry fixtures
Bulk-produce stable effective-dose labels for synthetic datasets and regression tests, with hard invalid_input on a negative absorbed dose.