An ND filter calculator tells you the correct shutter speed to use after adding a neutral density filter to your lens. Enter your base exposure (the shutter speed without the filter), select the ND filter strength, and the tool instantly shows the adjusted exposure time. The full exposure chart below lists every common ND strength from 1 to 15 stops so you can compare options at a glance.
Filter Settings
Result
Full ND Filter Exposure Chart
All ND strengths for your selected base shutter speed
| Stops | Filter Name | Factor | Exposure Time |
|---|
How to Use the ND Filter Calculator
Neutral density filters are one of the most powerful creative tools in landscape and video photography. They block light without changing color, letting you use longer shutter speeds in bright conditions to capture silky water, blur crowds, and create cinematic motion effects. This ND filter calculator removes the guesswork by doing the exposure math instantly.
Step 1: Meter Without the Filter
First, take a test shot or use your camera's live meter to find the correct exposure without the ND filter attached. Note the shutter speed that gives you proper exposure at the aperture and ISO you want to use. This is your base shutter speed. Select it from the dropdown in the calculator.
Step 2: Choose Your ND Filter
Select the strength of your ND filter from the dropdown. Common filters are ND64 (6 stops, great for golden-hour water shots), ND1000 (10 stops, for daytime long exposures), and ND32000 (15 stops, for extreme slow-shutter photography in bright sun). Each stop doubles the exposure time — 6 stops multiplies your base by 64, and 10 stops multiplies by 1024.
Step 3: Read the Adjusted Shutter Speed
The result panel shows the new shutter speed to dial into your camera after attaching the filter. For exposures over 30 seconds, use your camera's BULB mode with a cable release or remote shutter trigger to hold the shutter open for the exact calculated time.
Step 4: Consult the Exposure Chart
The full exposure chart below the calculator shows every standard ND strength from 1 to 15 stops for your current base shutter speed. Use this to compare results across different filters or to decide which filter to pack for a shoot. The highlighted row matches your selected filter, making it easy to scan.
Tips for Accurate Long Exposures
Use a sturdy tripod and a cable or wireless shutter release to eliminate camera shake. Focus and compose before attaching the ND filter, since very dark filters make it nearly impossible to see through the viewfinder. If using a 10-stop or stronger filter, also disable autofocus to prevent the camera from hunting. For exposures over a minute, factor in reciprocity failure if you are shooting film.
FAQ
Is this ND filter calculator free?
Yes, this ND filter calculator is completely free with no account, login, or signup required. All calculations run instantly in your browser and no data is sent to any server.
Is my data private when using this tool?
Absolutely. Everything runs locally in your browser. No settings or calculations are transmitted or stored anywhere. You can bookmark the page and use it offline once loaded.
What is an ND filter and why do I need it?
A neutral density (ND) filter is a piece of dark, optically neutral glass placed in front of the lens. It reduces the amount of light entering the camera without affecting color, allowing you to use slower shutter speeds or wider apertures in bright conditions for creative effects like silky water and motion blur.
What do ND filter stop numbers mean?
Each stop of an ND filter halves the amount of light passing through. A 3-stop ND filter (ND8) blocks 87.5% of light, requiring an 8× longer exposure. A 10-stop ND filter (ND1000) blocks 99.9% of light, extending a 1/60s shot to about 17 seconds.
What is the difference between ND8, ND64, and ND1000?
The number after 'ND' is the filter factor — how many times longer the shutter must stay open. ND8 = 3 stops (8× longer), ND64 = 6 stops (64× longer), ND1000 = 10 stops (1000× longer). Higher numbers mean darker filters for longer exposures.
How do I calculate shutter speed with an ND filter?
Multiply your base shutter speed (the correct exposure without the filter) by the filter factor. For example, if your base is 1/125s and you use an ND64 filter, the new time is 1/125 × 64 = 0.51 seconds. This calculator does the math instantly for all filter strengths.
Can I stack multiple ND filters?
Yes. To stack filters, add their stop values together. A 3-stop ND and a 6-stop ND together act like a 9-stop ND filter. Note that stacking filters can introduce vignetting and reduce optical quality compared to a single high-quality variable ND filter.
What ND filter do I need for video in bright sunlight?
For video, the 180-degree shutter rule recommends a shutter speed of 1/(2 × frame rate). At 24fps you want 1/48s. In bright daylight you may need an ND64 or ND1000 to achieve that speed. At 30fps you want roughly 1/60s, often requiring an ND8 to ND64 depending on conditions.