Does HEIC to JPG Conversion Lose Quality?
Yes — and the reason is fundamental to how lossy compression works. HEIC uses HEVC (H.265) compression, while JPG uses DCT-based JPEG compression. These are two entirely different algorithms that discard different parts of image data. When you convert from HEIC to JPG, the image is first decoded (decompressed) from HEVC, then re-encoded (recompressed) into JPEG. Each encoding pass discards information that cannot be recovered.
This is called generation loss — the same phenomenon that makes photocopying a photocopy progressively worse. The HEIC original already threw away some data during the initial compression on your iPhone. The JPG encoding throws away additional data. The result is always technically inferior to the HEIC source.
However, "technically inferior" does not mean "visibly worse." At high quality settings (92 and above), the generation loss is below the threshold of human perception. The key is choosing the right quality level for your needs.
What JPEG Quality Levels Mean
JPEG quality is specified as an integer from 1 to 100. This number controls the quantization table — a matrix that determines how aggressively the encoder rounds off frequency coefficients in each 8×8 pixel block. Lower quality means more aggressive rounding, which means smaller files but more visible artifacts.
It is important to understand that quality 100 does not mean lossless. JPEG is always lossy. Quality 100 simply uses the least aggressive quantization table, producing the largest file with the least compression artifacts. True lossless conversion would require a format like PNG or TIFF.
| Quality | File Size* | Size vs HEIC | Visual Quality |
|---|---|---|---|
| 100 | ~9–12 MB | 4–5x larger | Maximum fidelity. No visible artifacts. Overkill for most use cases. |
| 95 | ~5–7 MB | 2–3x larger | Indistinguishable from quality 100 in side-by-side tests. |
| 92 (default) | ~3.5–5 MB | 1.5–2x larger | Visually lossless. Best quality-to-size ratio for general use. |
| 85 | ~2–3 MB | ~Same size | Minor artifacts in smooth gradients (sky, skin tones). Fine for web and social media. |
| 80 | ~1.5–2.5 MB | ~0.7x smaller | Slight softening of fine detail. Good balance for email attachments. |
| 70 | ~1–1.8 MB | ~0.5x smaller | Noticeable blocking in detailed areas. Text edges may blur. |
| 60 | ~0.7–1.2 MB | ~0.4x smaller | Visible compression artifacts. Color banding in gradients. Acceptable for thumbnails. |
*File sizes for a typical 12 MP iPhone photo (4032 × 3024 pixels). HEIC original is approximately 2–3 MB.
The 92 sweet spot: Below quality 90, file size drops quickly but artifacts become noticeable. Above 95, file size balloons but visual improvement is negligible. The range of 92–95 delivers the best return — virtually no visible loss at a reasonable file size. This is why Convertio defaults to quality 92.
Recommended Settings by Use Case
There is no single "correct" quality setting. The right choice depends on what you are doing with the converted file. Here are practical recommendations for the most common scenarios:
| Use Case | Quality | Resize? | Rationale |
|---|---|---|---|
| Archival / backup | 100 | No | Maximum fidelity. File size is secondary when preserving originals. |
| Printing (large format) | 95–100 | No | Print shops need high-resolution, high-quality files. Keep full 4032×3024. |
| Photo editing | 95–100 | No | Higher quality preserves more data for post-processing adjustments. |
| General sharing | 92 | No | The default. Visually lossless, universally compatible. |
| Email attachments | 80–85 | 1920px max | Most email providers cap attachments at 10–25 MB. Resizing and moderate compression keeps files under 1 MB each. |
| Web upload / blog | 75–85 | 1600–2000px | Page load speed matters. Nobody views blog images at full 4032px width. |
| Social media | 85–92 | Optional | Platforms (Instagram, Facebook) re-compress uploads anyway. Quality above 92 is wasted. |
| Thumbnails / previews | 60–70 | 300–600px | Small display size hides compression artifacts. File size is the priority. |
Optimizing for Email
Email is the most common reason people convert HEIC to JPG, and the most common complaint is "the file is too large to send." A 12 MP iPhone photo at quality 92 produces a 3.5–5 MB JPG. Attach five photos and you have hit the 25 MB limit for Gmail.
The most effective optimization is combining a quality reduction with resizing. A 4032×3024 photo displayed on a laptop screen (typically 1920×1080) has far more pixels than needed. Resizing to 1920px on the long edge and using quality 80–85 produces files around 400–700 KB each — small enough to attach a dozen photos in a single email while still looking sharp on any screen.
Optimizing for Web
For website images, page load speed directly affects user experience and search engine rankings. Every 100 KB saved across your images adds up to faster page loads. Resize to the maximum display width of your site (typically 1200–1600px for content images) and use quality 75–85. At these dimensions and quality levels, compression artifacts are virtually invisible on screen.
Display P3 to sRGB: Color Space Conversion
Starting with iPhone 7, Apple cameras capture photos in the Display P3 color space, which is approximately 25% wider than the standard sRGB gamut. This means iPhones can record colors — particularly vivid reds, oranges, and greens — that sRGB cannot represent.
When you convert HEIC to JPG, the color profile is typically mapped from Display P3 to sRGB. This happens because most software, browsers, and displays still assume sRGB as the default color space. Here is what this means in practice:
| Color Range | P3 Original | sRGB Result | Visible Difference |
|---|---|---|---|
| Deep reds / oranges | Full gamut | Clipped to sRGB boundary | Slight desaturation in vivid sunsets, autumn leaves |
| Saturated greens | Full gamut | Clipped to sRGB boundary | Bright foliage may appear slightly muted |
| Blues / cyans | Overlap with sRGB | Mostly preserved | Minimal — P3 and sRGB overlap closely in blue range |
| Skin tones / neutrals | Within sRGB | Identical | None — these colors exist in both spaces |
For the vast majority of photos — portraits, indoor shots, food, everyday scenes — the color shift is undetectable. The only scenario where you might notice a difference is with extremely saturated natural colors: a tropical sunset, neon signs, or bright autumn foliage. Even then, the difference is subtle and only visible in a direct side-by-side comparison on a wide-gamut display.
Tip: If color accuracy is critical for your work (photography, design, printing), convert to TIFF or PNG instead of JPG. These formats support embedded P3 profiles and lossless compression, preserving the full color gamut. For everything else, sRGB JPG is the pragmatic choice.
EXIF Metadata: Keep or Strip?
Every iPhone photo embeds EXIF metadata — a block of data that records camera settings, date and time, GPS coordinates, device model, lens information, and more. When converting HEIC to JPG, you can either preserve this data or strip it. The choice depends on how you plan to use the file.
| Scenario | Recommendation | Why |
|---|---|---|
| Personal archive | Keep | Date, GPS, and camera info help you organize photos later. Photo management apps rely on EXIF data for sorting and search. |
| Printing | Keep | Print services use orientation tags and color profile data. Stripping EXIF can cause photos to print rotated or with wrong colors. |
| Social media | Either | Platforms like Instagram and Facebook strip EXIF during upload anyway. Stripping beforehand saves a few KB but has no practical effect. |
| Sharing online | Strip | EXIF contains GPS coordinates that reveal where the photo was taken. Remove metadata before posting on forums, blogs, or sending to strangers. |
| Web / blog images | Strip | Reduces file size by 10–50 KB per image. Also removes camera serial numbers and location data from publicly accessible files. |
EXIF data typically adds 10–50 KB to each JPG file. For a single photo, this is negligible. For hundreds of web images, stripping metadata provides a meaningful cumulative size reduction and eliminates potential privacy leaks.
Why Are JPG Files Larger Than HEIC?
One of the most common surprises when converting HEIC to JPG: the output file is bigger than the input. This is not a bug — it is a direct consequence of how the two compression algorithms compare.
HEIC uses HEVC (H.265) compression, which was designed in 2013 with modern computational techniques: variable block sizes (up to 64×64), advanced intra prediction, sample adaptive offset filtering, and context-adaptive binary arithmetic coding (CABAC). JPEG, designed in 1992, uses fixed 8×8 blocks and simpler entropy coding.
The result: HEVC is approximately 50% more efficient than JPEG at the same visual quality. A 2 MB HEIC file at quality 92 contains the same visual information as a 3.5–5 MB JPG at quality 92. The JPG is larger because its compression algorithm needs more bytes to represent the same image data at the same perceived quality level.
To reduce JPG file size: Lower the quality setting (80–85 produces files roughly the same size as the HEIC original), resize to a smaller resolution, or both. A 1920px-wide JPG at quality 85 is typically 500–800 KB — smaller than the original HEIC.
Practical Conversion Workflow
Here is a straightforward decision process for choosing quality settings when converting HEIC to JPG:
- Determine your output destination. Are these files for printing, emailing, web upload, personal archive, or social media?
- Choose quality based on the table above. When in doubt, use 92 — it works well for everything except thumbnails and large batch email sends.
- Decide on resizing. If the destination does not need 4032×3024 resolution (email, web, social), resize to 1920px or less on the long edge. This has a larger impact on file size than quality adjustments.
- Handle metadata. Keep EXIF for personal use and printing. Strip it for anything shared publicly online.
- Convert. Upload your HEIC files using the converter above. Adjust quality in the options panel before converting.