ABOUT NDTIME

One reference.
One clear calculation.

NDtime is a free, browser-based calculator for the shutter-duration effect of entered neutral-density filter strengths.

Its useful part is keeping the label conventions visible. Stops, optical density and filter factor are separate input choices. Multiple filters can use different notations in the same stack, with their computed contributions shown individually.

No hidden photographic judgement

You supply the reference shutter duration. The tool does not meter a scene, inspect an image, choose equipment or promise a correct exposure. It uses ideal attenuation and leaves film reciprocity outside the model.

Free calculator, local actions

The calculation runs in your browser without an account. Copy and text download are optional. Inputs are not saved in browser storage by the calculator.

Publisher identification is prepared for possible future advertising. This release has no active advertising, consent-management or analytics loader. It does not establish approval, active measurement, ads serving or earnings.

Read the method and label guide or report a reproducible issue.