ND Filter Calculator

A neutral density filter cuts light by a fixed number of stops so you can use a slower shutter speed in daylight: silky water, empty streets, motion blur. Pick your metered shutter speed and the filter, and the calculator gives the new exposure time.

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ND filter exposure

Shutter with filter

8.2 s

10 stops darker

Optical density

3.0

Keep aperture and ISO the same; only the shutter changes. Cover the viewfinder and use a tripod for anything over 1/4 s.

All filters at 1/125 s

FilterStopsNew shutter
ND211/63 s
ND421/31 s
ND831/16 s
ND1641/8 s
ND3251/4 s
ND6461/2 s
ND12871 s
ND25682 s
ND4008.63.1 s
ND1000108.2 s
ND32000154 min 22 s
ND10000016.613 min 15 s

Reading ND numbers

NameStopsDensityLight passed
ND830.91/8
ND6461.81/64
ND1000103.01/1000
ND10000016.65.01/100000 (solar)

Stack filters by adding their stops. Beyond about 30 s most cameras need bulb mode and a timer.

All eight calculators live on the camera calculators page.

Questions people ask

How many stops is an ND1000?

Ten stops (optical density 3.0): it lets through 1/1000 of the light. 1/125 s becomes about 8 s. ND8 is three stops, ND64 six, ND400 about 8.6 stops.

What ND filter for waterfalls?

A 6-stop (ND64) filter usually gets you from 1/60 s to 1 s in shade, enough for silky water; use ND1000 in bright sun. For video at 1/50 s in daylight, a 3–6 stop variable ND is the usual choice.

Do ND filters change color?

Cheap ones add a magenta or brown cast, especially at 10 stops. Set white balance from a neutral in the scene or fix it afterwards by sampling a neutral point.

What shutter speed should I use with a 10-stop ND filter?

Multiply the unfiltered shutter time by 1,024: 1/125 s becomes about 8 s, 1/60 s about 16 s. https://whitebalancer.com/tools/nd-filter-calculator converts any shutter speed for ND2 through ND100000.

Which ND filter do I need for a 30-second exposure in daylight?

From a typical 1/125 s daylight exposure you need 12 stops (ND4000), or a 10-stop ND1000 plus a smaller aperture. Check the exact combination at https://whitebalancer.com/tools/nd-filter-calculator.

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