---
title: "NEP & Detectivity (D*) calculator — AperiOptic"
description: "Convert between NEP, area, bandwidth and specific detectivity D*. Free online optics calculator, with the formula and code snippets."
url: "https://aperioptic.com/calculators/nep-detectivity-d"
---

# NEP & Detectivity (D*) calculator

Convert between NEP, area, bandwidth and specific detectivity D*.

Category: [Detectors](https://aperioptic.com/calculators)

Formula: `D* = √A / NEP (NEP in W/√Hz; = √(A·Δf)/NEP for an NEP in W over Δf)`

## Inputs

| Input | Parameter | Unit | Default |
| --- | --- | --- | --- |
| NEP | `NEP` | W/√Hz | 1e-14 |
| Area A | `A` | mm² | 1 |
| Bandwidth Δf | `BW` | Hz | 1 |

## Result with the default inputs

- D*: 1.0000e+13 cm·√Hz/W
- Min detectable P: 1.0000e-14 W

Open it with your own values: put each input in the address as a parameter, for example [`/calculators/nep-detectivity-d?NEP=1e-14`](https://aperioptic.com/calculators/nep-detectivity-d?NEP=1e-14). A unit other than the listed one goes in `<parameter>_unit`.

Read more: [Wikipedia: Noise-equivalent power](https://en.wikipedia.org/wiki/Noise-equivalent_power)

[All optics calculators](https://aperioptic.com/calculators)

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The interactive page: https://aperioptic.com/calculators/nep-detectivity-d (AperiOptic runs in the browser; free, no account). Every page of the site as Markdown: https://aperioptic.com/llms.txt