Updated · how we check
Resize an image to 3840×2160 pixels (4K UHD)
To resize an image to 3840×2160 px, enter 3840 × 2160 px and pick crop to fill so the 16:9 frame is not stretched: a 4:3 phone photo loses 25% of its area (a centred 4032×2268 crop). The result has 8.29 megapixels; as a JPEG, a detailed outdoor photo is about 2.38 MB at the panel's default quality 85 (1.8 MB at quality 75, extrapolated).
3840×2160 px
JPG · no file-size limit · 3840x2160 px · white background
No file-size limit is set: PixelFit saves at high quality and changes only the format and any pixel size you set.
Fit, background and padding crop to fill · white background
Saving presets is part of Pro.
The result appears here: the exact byte count, pixel size and quality, the size before and after, a preview and a download button.
The batch kit (one ZIP for up to 500 photos, several photos merged into one PDF) is part of Pro.
3840×2160 at a glance
| Pixel size | 3840×2160 px (8,294,400 pixels) |
|---|---|
| Aspect ratio | 16:9, landscape (width ÷ height = 1.7778) |
| Megapixels | 8.29 MP |
| Decoded in memory | 31.6 MB RGBA · 23.7 MB RGB |
| Sharp on screen at | 3840×2160 CSS px at 1×, 1920×1080 at 2×, 1280×720 at 3× density |
| Print size at 300 DPI | 12.8×7.2 in (32.5×18.3 cm) |
| Estimated JPEG (outdoor photo, quality 75) | 1.8 MB (extrapolated) |
| JPEG without a KB limit (panel default, quality 85) | 2.38 MB (extrapolated) |
What 3840×2160 means in pixels
3840×2160 is a landscape frame, 1.78 times as wide as it is tall, 8,294,400 pixels in total (8.29 megapixels). Its sides reduce to 16:9 (1.7778 as a decimal), so any picture cropped to 16:9 scales to it without distortion.
That is 68% of a 12 MP phone frame, close to the most a phone delivers; after the crop the picture is scaled by 0.952×, so check edges and text at 100% zoom. Shown 1:1 it fills 3840×2160 CSS px on a standard screen and 1920×1080 CSS px on a 2× (Retina-class) screen; at 72 DPI the same pixels span 53.3×30 inches.
Decoded for editing it occupies 31.6 MB of memory (4 bytes per pixel); uncompressed 24-bit RGB would be 23.7 MB, which is why the downloadable JPEG, PNG or WebP is far smaller.
Where 3840×2160 is used
Each line comes from the reference listed under Sources, checked October 2026.
- 4K UHD display resolution.
- YouTube recommended custom thumbnail resolution for videos. YouTube asks for a minimum width of 640 pixels.
Getting 3840×2160 from a phone, camera or screenshot
Filling 3840×2160 from a Full HD screenshot (1920×1080, 16:9) loses nothing; a vertical phone video frame (1080×1920, 9:16) loses the most (68.3%). "Fit inside" keeps the whole picture instead and the file comes out at the size in the last column; "Pad with colour" adds bars to reach the full 3840×2160.
| Starting image | Crop to fill keeps | Area lost | Scale | Fit inside gives |
|---|---|---|---|---|
| 12 MP phone photo (4032×3024, 4:3) | 4032×2268 (top and bottom cut) | 25% | 0.952× (reduced) | 2880×2160 |
| 24 MP camera photo (6000×4000, 3:2) | 6000×3375 (top and bottom cut) | 15.6% | 0.64× (reduced) | 3240×2160 |
| Full HD screenshot (1920×1080, 16:9) | 1920×1080 (nothing cut) | 0% | 2× (enlarged) | 3840×2160 |
| Vertical phone video frame (1080×1920, 9:16) | 1080×608 (top and bottom cut) | 68.3% | 3.556× (enlarged) | 1215×2160 |
When 3840×2160 means enlarging
After the crop to fill, the kept region has to be enlarged 2× from a Full HD screenshot and 3.556× from a vertical phone video frame. Enlarging adds pixels but no detail, so start from the largest original you have, or choose a smaller target if the destination allows it: 3000×2000 landscape or 2560×1600 (WQXGA) would need less stretching.
How many KB is a 3840×2160 image?
Estimated from encodes of real sample images measured with sharp 0.35.5 / libvips 8.18.7 on 31 October 2026, interpolated to 8,294,400 pixels; this size lies outside the measured range, so the figures are extrapolated. The outdoor photo at 3840×2160 is about 1.8 MB at quality 75 and a scanned page about 732 KB; your file will differ with detail and noise.
| Image type | JPEG q60 | JPEG q75 | JPEG q90 | WebP q75 | PNG |
|---|---|---|---|---|---|
| Portrait photo | ≈ 438 KB | ≈ 638 KB | ≈ 1.24 MB | ≈ 286 KB | ≈ 8.37 MB |
| Outdoor photo | ≈ 1.38 MB | ≈ 1.8 MB | ≈ 2.93 MB | ≈ 1.51 MB | ≈ 14.9 MB |
| Scanned document | ≈ 526 KB | ≈ 732 KB | ≈ 1.34 MB | ≈ 357 KB | ≈ 7.37 MB |
| Flat graphic or logo | ≈ 116 KB | ≈ 135 KB | ≈ 187 KB | ≈ 63.4 KB | ≈ 183 KB |
Will a 3840×2160 photo fit an upload limit?
The highest JPEG or WebP quality that stays under each limit at exactly 3840×2160 px, from the same measurements. Set the KB limit next to the pixel size and PixelFit runs this search on your own photo.
| Limit | Portrait, JPEG | Outdoor photo, JPEG | Outdoor photo, WebP |
|---|---|---|---|
| Under 500 KB | up to quality 64 | does not fit even at quality 30 | does not fit even at quality 30 |
| Under 1 MB | up to quality 85 | up to quality 35 | up to quality 39 |
| Under 2 MB | fits at quality 95 | up to quality 78 | up to quality 82 |
Is 3840×2160 good for print?
Pixels carry no physical size until you pick a DPI. At 300 DPI, the resolution PixelFit uses for its print and ID photo sizes, 3840×2160 covers 12.8×7.2 in; at 150 DPI the same pixels stretch to 25.6×14.4 in with half the density.
| Resolution | Print size (inches) | Print size (cm) |
|---|---|---|
| 72 DPI | 53.33×30 in | 135.5×76.2 cm |
| 96 DPI | 40×22.5 in | 101.6×57.2 cm |
| 150 DPI | 25.6×14.4 in | 65×36.6 cm |
| 200 DPI | 19.2×10.8 in | 48.8×27.4 cm |
| 300 DPI | 12.8×7.2 in | 32.5×18.3 cm |
| 600 DPI | 6.4×3.6 in | 16.3×9.1 cm |
How 3840×2160 shows on common screens
Shown full screen without cropping, 3840×2160 is scaled by the factor below; bars fill the space where the shapes differ.
| Screen | Scale | Shown at | Bars |
|---|---|---|---|
| Laptop 1366×768 | 0.36× (reduced) | 1365×768 | none |
| Full HD 1920×1080 | 0.5× (reduced) | 1920×1080 | none |
| QHD 2560×1440 | 0.67× (reduced) | 2560×1440 | none |
| Phone, portrait 1080×1920 | 0.28× (reduced) | 1080×608 | 1312 px top and bottom in total |
Other 16:9 sizes
These targets share the exact 16:9 ratio of 3840×2160, so resizing between them is a pure scale with nothing cropped.
| Size | Scale from 3840×2160 | Megapixels |
|---|---|---|
| 5120×2880 (5K) | 1.33× | 14.7 MP |
| 2560×1440 (QHD) | 0.67× | 3.69 MP |
| 7680×4320 (8K UHD) | 2× | 33.2 MP |
| 1920×1080 (FHD) | 0.5× | 2.07 MP |
| 1600×900 (HD+) | 0.42× | 1.44 MP |
| 1280×720 (HD) | 0.33× | 0.92 MP |
| 1200×675 landscape | 0.31× | 0.81 MP |
| 960×540 (qHD) | 0.25× | 0.52 MP |
How to resize a picture to 3840×2160
-
Add the picture
Drop, paste or pick the photo in the PixelFit panel at the top of this page; it is decoded in your browser and never uploaded.
-
Set the size
Enter 3840 as the width and 2160 as the height in pixels (the panel is already set to 3840×2160).
-
Choose how it fits
Choose crop to fill to keep the 16:9 frame without stretching (a phone photo loses 25%, top and bottom cut). Fit inside keeps the whole picture as a 2880×2160 file instead; Pad with colour puts that on a full 3840×2160 canvas.
-
Pick the format and download
Choose JPG or WebP; without a KB limit PixelFit saves JPG at quality 85, about 2.38 MB for a detailed outdoor photo. Add a KB limit if the upload has one or the file should be smaller, then download the 3840x2160 file.
Sources
- Display resolution standards, Wikipedia, checked 31 October 2026: en.wikipedia.org/wiki/Display_resolution_standards
- Add video thumbnails, YouTube Help, checked 31 October 2026: support.google.com/youtube/answer/72431?hl=en
- Measured by PixelFit with sharp 0.35.5 / libvips 8.18.7 on 31 October 2026, from the sample photo Hartz Lake at Hartz Mountain.jpg by JustinH (Wikimedia Commons user) (CC0 1.0): commons.wikimedia.org/wiki/File:Hartz_Lake_at_Hartz_Mount…
Frequently asked questions
How do I resize an image to 3840x2160?
Open the image in the PixelFit panel on this page, set 3840 × 2160 px, choose crop to fill so nothing is stretched and download. From a 12 MP phone photo that crops 25% (top and bottom cut) and scales the rest by 0.952×.
What aspect ratio is 3840x2160?
3840x2160 has an aspect ratio of 16:9: landscape, width ÷ height = 1.7778. Sizes with the same ratio include 5120×2880 (5K), 2560×1440 (QHD) and 7680×4320 (8K UHD).
Is 3840x2160 good for print?
At 300 DPI 3840x2160 prints 12.8×7.2 in (32.5×18.3 cm), enough for a print of that size at full density. At 150 DPI it stretches to 25.6×14.4 in.
How big is a 3840x2160 JPEG file?
For a detailed outdoor photo about 1.8 MB at quality 75 (1.38 MB at 60, 2.93 MB at 90, 2.38 MB at the panel's default quality 85); a head-and-shoulders portrait is about 638 KB at quality 75, extrapolated from encodes of real sample photos measured up to 6.75 MP (3840×2160 px lies outside that range). A flat graphic is smaller, a noisy low-light photo larger.
Related
Same 16:9 ratio
Nearby sizes
- 4096×2160 (DCI 4K) 256:135 (about 1.91:1)
- 3000×2000 landscape 3:2
- 2560×1600 (WQXGA) 8:5
- 4000×3000 landscape 4:3
- 3440×1440 (UWQHD) 43:18 (2.39:1)
- 2400×1600 landscape 3:2