Camera Memory Card Capacity Calculator

Shoot preset:

Choose a common camera job, then replace the values with the actual camera-menu settings.

Card size:

Use one card's labeled capacity, such as 64, 128, 256, or 512 GB.

GB/card

Cards packed:

Count the physical cards available for this shoot.

cards

Recording mode:

Choose how the camera consumes cards during the shoot.

Still photos:

Enter the expected number of captured frames.

photos

Photo size source:

Use measured sample files when the camera and compression settings are known.

Camera resolution:

Typical values include 24, 33, 45, and 61 MP.

Photo format:

Choose the format used for most of the planned frames.

Average photo file:

Enter the average size of representative files.

MB/photo

Video runtime:

Set to 0 for stills-only planning.

min

Video profile:

Resolution alone does not determine storage; the actual bitrate does.

Video bitrate:

Use the exact camera-menu value when available.

Mb/s

Selected card speed:

Choose the printed V/U class or a verified sustained-write tier.

Spare reserve:

{{ reserve_pct }}%

A 10–20% reserve is a practical starting point for critical shoots.

Exact reserve %

Burst rate:

Set both burst rate and duration to 0 when burst recovery is not relevant.

fps

Longest burst:

Enter the longest continuous burst expected during the shoot.

Burst recovery target:

Use the maximum acceptable time before another full burst.

Capacity basis:

Keep decimal GB for ordinary card-label planning.

Measure	Value	Planning note	Copy
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Check	Value	Decision	Copy
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Card size	Physical cards	Capacity margin	Use case	Copy
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Memory-card planning has two separate failure points. A card set can hold the expected photos and video yet write too slowly for the selected recording mode, or it can meet the speed requirement and still run out of space before the shoot ends.

Storage depends on the amount of media and the size of each unit. Still-photo files vary with sensor resolution, format, compression, detail, and camera processing. Video size follows bitrate and recorded minutes rather than event duration or resolution alone. Representative files from the actual camera are more dependable than a format estimate.

Three separate camera memory-card planning questions
Question	What controls it	Typical mistake
Capacity	File count, average photo size, video bitrate, runtime, and reserve	Using megapixels or video resolution without checking real file size or bitrate
Redundancy	Single-slot, overflow, or mirrored dual-slot recording	Counting both cards in a mirrored pair as extra usable space
Write speed	Continuous video demand and burst-buffer recovery	Reading the advertised peak speed instead of the minimum sustained class

A spare reserve protects against extra takes, longer clips, and file-size variation, but it cannot fix an incompatible card or a slow write path. Dual-slot backup also trades capacity for protection by writing the same media to both cards. An unmatched card in a packed set does not complete another mirrored pair.

The result is a shoot plan, not a camera compatibility guarantee. The camera manual and its approved-media list can impose card type, capacity, bus, codec, or sustained-write requirements beyond a generic speed mark.

How to Use This Tool:

Build the plan from the camera's actual settings whenever they are available.

Enter one card's labeled Card size, the number of physical Cards packed, and the recording mode. Choose Dual-slot backup mirror only when both slots write the same copy.
Enter the expected frame count. Select Measured average file size when you have representative files from the same camera, format, compression, and scene type.
Add recorded video minutes and use the bitrate shown in the camera menu or manual. Set video minutes to 0 for a stills-only plan.
Choose the card's minimum sustained speed class and set a reserve. Add burst rate, duration, and recovery time only when clearing the still-photo buffer matters.
Check both the capacity decision and Write-speed check. If either reports a shortfall, add paired cards for mirrored recording, select larger media, or use a verified faster class before the shoot.

Interpreting Results:

Required storage includes stills, video, and the chosen reserve before the result rounds up to whole cards. Packed margin above 0 means the usable packed set covers the estimate; a negative margin is the missing capacity.

In single-slot and overflow modes, every packed card contributes capacity. In dual-backup mode, capacity is counted per complete pair.
Required physical cards is doubled for mirrored recording. Three cards provide only one usable mirrored pair, not one and a half pairs.
A Write speed result of Review means the selected class is below the greater of the video requirement with headroom and the burst-recovery requirement.
Passing the modeled speed check does not prove that the camera supports the card, codec, or recording mode. Confirm the manufacturer list before a critical shoot.

Technical Details:

Capacity is modeled in megabytes. Decimal card labels use 1 GB = 1,000 MB; the optional binary comparison uses 1 GiB = 1,024 MiB. The latter is useful for comparing 1024-based readouts, but ordinary card-label planning should use decimal units.

Lookup Core

When no measured average is supplied, photo size is estimated from megapixels with these planning coefficients. They are not manufacturer specifications.

Estimated photo-size coefficients by photo format
Photo format	Estimated MB per megapixel
JPEG fine	0.45
Compressed RAW	1.15
Lossless RAW	1.45
RAW + JPEG fine	1.60

Formula Core

Total media is the sum of still storage and video storage, increased by the reserve percentage.

M_{required} = (N \times F + \frac{b}{8} \times 60 \times t) \times (1 + \frac{r}{100})

N is still count, F is average photo size in MB, b is video bitrate in Mb/s, t is recorded minutes, and r is reserve percentage. Dividing bitrate by 8 converts megabits per second to megabytes per second.

Cards per slot round up because a partial card is not usable. Mirrored recording doubles the physical count but not the capacity available to one copy.

C_{slot} = ⌈ \frac{M_{required}}{M_{card}} ⌉

Sustained-write demand uses the larger of video bitrate with 20% headroom and the rate needed to clear the longest still burst within the requested recovery time.

W_{required} = \max (1.2 \times \frac{b}{8}, \frac{q \times d \times F}{c})

q is burst frames per second, d is burst duration, and c is the recovery target in seconds. The recommendation moves to the smallest modeled tier at or above the result: 10, 30, 60, 90, 400, or 800 MB/s. A demand above those tiers is reported for manufacturer-list review.

Accuracy Notes:

The largest uncertainty is usually the average photo file size. Compression changes with subject detail and camera settings, so average several files from a representative session. Video bitrate presets are examples; the exact menu value is better.

Formatted capacity can be lower than the printed label, and cameras may reserve space for file systems or databases.
Burst recovery is a planning estimate. Camera buffer size, internal processing, card bus, fragmentation, and thermal limits can change real clearing time.
Speed-class symbols describe minimum performance under defined conditions. Camera-specific media approval remains the final compatibility check.

Worked Example:

Mirrored hybrid wedding coverage

At 33 MP, the RAW + JPEG estimate is 52.8 MB per frame. For 2,400 stills and 90 minutes at 150 Mb/s, media totals 227,970 MB before reserve and 273,564 MB after a 20% reserve. Three 128 GB cards are needed per slot, so mirrored recording requires six physical cards. A burst of 8 fps for 5 seconds with a 30-second recovery target needs 70.4 MB/s; V60 falls short, so the modeled recommendation moves to V90.

References:

Speed Class Standards for Video Recording, SD Association.
Capacity (SD/SDHC/SDXC/SDUC), SD Association.