How is photo file size calculated?

For lossless formats, file size equals total pixels times channels times bit depth divided by 8. For lossy formats like JPEG and HEIC, file size is approximated as total pixels times an empirical bytes-per-pixel coefficient (about 0.6 for JPEG-High Q85 and 0.3 for HEIC) because compression efficiency depends on image content.

Why is RAW so much larger than JPEG?

RAW files store the full sensor readout at 12 to 16 bits per pixel before any tone curve, white balance, or noise reduction is baked in. A JPEG bakes those choices in and uses lossy DCT compression that throws away information the human eye is unlikely to notice. The result is that RAW typically produces files 5 to 15 times larger than a JPEG-High of the same scene.

Are these file size estimates exact?

No. Lossy compression depends heavily on image content — a flat blue sky compresses to a tiny fraction of a detailed forest scene at the same JPEG quality. The estimates use bytes-per-pixel constants derived from typical photographic content, so expect the real file size of any single photo to vary by 30 to 50 percent in either direction. Average across many photos and the totals match closely.

What is HEIC and why is it smaller than JPEG?

HEIC (High Efficiency Image Container) is built on the HEVC video codec. HEVC uses much more sophisticated block-prediction and entropy coding than JPEG's older DCT pipeline, which lets HEIC produce files about half the size of a JPEG at visually identical quality. Modern iPhones and many Android phones save HEIC by default.

How many photos fit on a 64 GB SD card?

It depends on the camera and format. For a 24 MP camera shooting JPEG-High the answer is roughly 4,400 photos. For the same camera shooting 14-bit lossless RAW it drops to about 950. For a 61 MP camera shooting RAW expect closer to 360 photos on the same 64 GB card. Use the storage capacity panel above for an exact estimate at your settings.

Should I shoot in RAW or JPEG?

Shoot RAW if you plan to edit (color grade, recover highlights, adjust white balance later) and have storage to spare. Shoot JPEG if you want files ready to share, smaller storage footprint, and trust the camera's color science. Many cameras also offer RAW plus JPEG, which doubles file size but gives you both options.

Photo File Size Estimator

Estimate the file size of a photo in JPEG, RAW, TIFF, HEIC, and PNG formats from megapixels, bit depth, and quality. See exactly how many photos fit on your SD card, SSD, or hard drive.

📷 Camera Presets tap to load typical settings

🔢 Megapixels

📐 Aspect Ratio

🎨 Bit Depth

⚙️ JPEG Quality (for headline result)

Enter megapixels to see pixel dimensions

Embed Photo File Size Estimator Widget

About Photo File Size Estimator

The Photo File Size Estimator predicts how large a single photo will be on disk across every common image format — JPEG (Low, Medium, High, Maximum), HEIC, PNG, TIFF, and RAW — from just three inputs: megapixel count, aspect ratio, and bit depth. Photographers use it to plan SD card capacity before a trip, decide between RAW and JPEG when storage is tight, and budget cloud storage for large libraries. The same estimates apply whether you shoot with a smartphone, a mirrorless body, a DSLR, or a medium-format camera.

How Photo File Size Is Calculated

Image file size depends on three things: how many pixels the photo contains, how many bits encode each pixel, and how aggressively the format compresses redundant data. Lossless formats follow a clean formula. Lossy formats (JPEG, HEIC) only follow an approximation, because their compressor exploits perceptual tricks that depend on image content.

📐 Lossless formula (TIFF, PNG, RAW)

file size = pixels × channels × bit_depth ÷ 8

For an 8-bit RGB TIFF at 24 megapixels: 24,000,000 × 3 × 8 ÷ 8 ≈ 72 MB. RAW saves only one channel per pixel (the Bayer mosaic), so it is roughly one third of an uncompressed RGB file at the same bit depth, then a further ~35% smaller after lossless compression.

📷 Lossy approximation (JPEG, HEIC)

file size ≈ pixels × bytes_per_pixel

The bytes-per-pixel coefficient is empirical — it depends on the encoder, the quality setting, and how much detail the photo contains. The estimator uses values that match typical mid-detail photographic content:

JPEG Low (Q40): ~0.15 bytes/pixel
JPEG Medium (Q70): ~0.35 bytes/pixel
JPEG High (Q85): ~0.60 bytes/pixel — the recommended balance
JPEG Maximum (Q95): ~1.20 bytes/pixel
HEIC: ~0.30 bytes/pixel — about half the size of JPEG-High at matching visual quality

Reference Table — File Sizes at Common Megapixel Counts

The table below uses JPEG-High (Q85) for lossy formats and 14-bit for RAW. Real file sizes for individual photos can vary by 30 to 50 percent depending on scene content. Big skies, smooth surfaces, and out-of-focus areas compress aggressively; dense foliage, grain, and textile patterns do not.

Megapixels	JPEG High	HEIC	PNG (8-bit)	TIFF (16-bit)	RAW (14-bit)
12 MP	~7 MB	~3.6 MB	~36 MB	~72 MB	~14 MB
24 MP	~14 MB	~7.2 MB	~72 MB	~144 MB	~27 MB
36 MP	~22 MB	~11 MB	~108 MB	~216 MB	~41 MB
45 MP	~27 MB	~14 MB	~135 MB	~270 MB	~51 MB
61 MP	~37 MB	~18 MB	~183 MB	~366 MB	~70 MB
100 MP	~60 MB	~30 MB	~300 MB	~600 MB	~114 MB
200 MP	~120 MB	~60 MB	~600 MB	~1.2 GB	~228 MB

Bit Depth and Why It Matters

Bit depth is the number of binary digits used to store each color channel of each pixel. It controls how many distinct levels of brightness or color the format can represent — and it has a linear effect on file size for lossless formats.

8-bit: 256 levels per channel. JPEG, HEIC, and most web images. Sufficient for finished photographs but limits editing latitude.
10-bit: 1,024 levels. Used by HEIC on modern iPhones, Pixel, and Galaxy phones for richer gradients in the sky and skin tones.
12-bit: 4,096 levels. Default for entry-level mirrorless RAW capture. Preserves enough headroom for moderate exposure correction.
14-bit: 16,384 levels. Standard for professional mirrorless and DSLR RAW. Supports aggressive shadow recovery and white-balance adjustment.
16-bit: 65,536 levels. Used in TIFF for archival exports and by high-end film scanners. Beyond what current sensors actually capture.

How to Use the Photo File Size Estimator

Pick a camera preset for instant settings, or enter your own megapixel count.
Select an aspect ratio. 3:2 covers most DSLR and mirrorless bodies; 4:3 is right for smartphones and Micro Four Thirds.
Choose bit depth. 8-bit for JPEG-only workflows, 14-bit for RAW shooters, 16-bit for archival TIFF exports.
Set the JPEG quality that matches your headline result. The other formats are computed automatically.
Read the bar chart for at-a-glance comparison and the storage matrix for "how many fit" answers across SD cards, SSDs, and hard drives.

Why JPEG Estimates Are Approximate

JPEG compression uses a discrete cosine transform and quality-controlled quantization. Smooth areas (a clear sky) lose almost no perceptible detail and compress 10× more efficiently than detailed areas (rich foliage, fabric, hair). The estimator uses average bytes-per-pixel from typical mid-detail photographs. Two photos at the same camera, same JPEG quality, can differ by 2× or more — flat scenes always come in smaller than expected, and busy scenes always come in larger. For a single SD card or one trip, plan for the larger end of the range; over a year of shooting, the average converges.

Storage Planning Tips

Always reserve 10-15% headroom on SD cards. A "64 GB" card formats to about 59.6 GiB, and you don't want to be hunting for room mid-shoot.
RAW + JPEG doubles your file size, not adds 20%. If your card holds 800 RAW files alone, expect about 700 RAW+JPEG pairs.
Burst mode multiplies fast. A 20-fps mirrorless camera shooting 14-bit RAW can fill a 64 GB card in under five minutes of continuous shooting.
Cloud backup of RAW is expensive at scale. Most photographers archive selects only — keep RAW for keepers, JPEG for the rest.
HEIC is severely under-used. If your devices and software support it, HEIC delivers JPEG-grade quality at half the storage with no perceptible loss for most viewers.

Format Recommendations by Use Case

Web sharing, social media, email: JPEG Medium (Q70) or HEIC.
Personal photo library: JPEG High (Q85) or HEIC.
Editing for print or color grading: RAW, then export to JPEG Maximum or 16-bit TIFF.
Archival master copies: 16-bit TIFF or DNG (digital negative).
Graphics, screenshots, diagrams: PNG (lossless, sharp edges).

Frequently Asked Questions

How accurate are these estimates?

For lossless formats (TIFF, PNG, RAW) the estimates are accurate to within a few percent — the formula is deterministic. For lossy formats (JPEG, HEIC) the estimates use average bytes-per-pixel coefficients and individual photos can vary by 30 to 50 percent in either direction. Averaged across many photos, the totals match closely.

Why is my actual JPEG smaller than the estimate?

The most common reason is scene content: photos with large smooth areas (sky, water, walls) compress far better than the empirical average. Modern mobile encoders also tune JPEG more aggressively than the libjpeg defaults this tool uses. If your photos consistently come in 30 to 40 percent below estimate, your camera or software is using a more aggressive compression profile.

How big is a 200 MP photo from a Galaxy S24 Ultra?

At full 200 MP resolution the JPEG-High file is approximately 120 MB. In practice the S24 Ultra uses pixel binning to output 12 MP files by default (roughly 7 MB each) and only saves the full 200 MP version when you explicitly select that mode.

Does aspect ratio change the file size?

For a fixed megapixel count, aspect ratio only changes the width-to-height proportions, not the total pixel count. File size stays the same. Where aspect ratio matters is when you crop after capture — a 24 MP photo cropped to 16:9 becomes roughly an 18 MP file, which then has 25% smaller file size at the same JPEG quality.

What is the difference between RAW and DNG?

RAW is a category — every camera maker has a proprietary RAW format (Canon CR3, Nikon NEF, Sony ARW, Fujifilm RAF). DNG is Adobe's open RAW container that can wrap any camera's sensor data. DNG files are typically 10 to 20 percent smaller than the proprietary equivalents because Adobe applies more aggressive lossless compression by default.

Why is uncompressed TIFF so huge?

TIFF stores every pixel at full bit depth with no compression by default. A 16-bit TIFF stores 6 bytes per pixel (3 channels × 2 bytes). At 24 MP that produces a 144 MB file. TIFF does support LZW and ZIP compression, but for photographic content these only save 10 to 30 percent — far less than JPEG or HEIC achieve through lossy methods.

Additional Resources

Reference this content, page, or tool as:

"Photo File Size Estimator" at https://MiniWebtool.com/photo-file-size-estimator/ from MiniWebtool, https://MiniWebtool.com/

by miniwebtool team. Updated: May 2, 2026

Photo File Size Estimator

About Photo File Size Estimator

How Photo File Size Is Calculated

Reference Table — File Sizes at Common Megapixel Counts

Bit Depth and Why It Matters

How to Use the Photo File Size Estimator

Why JPEG Estimates Are Approximate

Storage Planning Tips

Format Recommendations by Use Case

Frequently Asked Questions

How accurate are these estimates?

Why is my actual JPEG smaller than the estimate?

How big is a 200 MP photo from a Galaxy S24 Ultra?

Does aspect ratio change the file size?

What is the difference between RAW and DNG?

Why is uncompressed TIFF so huge?

Additional Resources

Photography Tools:

Top & Updated: