2.5K resolution almost always means 2560 × 1440 pixels, the 16:9 frame also sold as QHD, WQHD or 1440p, and 4K means either 3840 × 2160 (UHD) or 4096 × 2160 (DCI). For both, the Playcut spec library gives the exact pixel counts, the action-camera 2.7K variants, the DCI-to-UHD crop math, a monitor resolution chart from 720p to 8K, and the 1K, 2K and 4K tiers each AI model in Playcut can output.
What 2.5K resolution means
2.5K is a marketing label for 2560 × 1440, not a standard: it is not defined in ITU-R BT.2020, the DCI specification or VESA's display standards. QHD ("Quad HD", four 1280 × 720 frames), WQHD and 1440p all name the same grid, and YouTube and many players file 1440p under "2K", which is where much of the 2K-versus-2.5K confusion starts.
Why manufacturers say 2.5K instead of 2K
The Wikipedia entry for 1440p, where its "2.5K resolution" page redirects, notes that some manufacturers prefer 2.5K for 2560 × 1440 to keep it distinct from the 2048 × 1080 cinema frame. As a number, 2560 is 2.56K, 2048 is 2.05K, 3840 is 3.84K and 4096 is 4.10K, which is why 4096 is the "true" 4K and UHD the rounded one.
2560 × 1600 (WQXGA): the laptop and portable-monitor 2.5K
On laptops, "2.5K" often means 2560 × 1600 instead, a 16:10 (8:5) frame called WQXGA with 4,096,000 pixels: 160 rows taller than QHD, 1.98 times Full HD and 49.4% of 4K UHD. It is a 16:10 frame, so do not file it with 3200 × 1800, the 16:9 laptop panel one step up.
3,686,400 pixels: 1.78 times Full HD, 44.4% of 4K UHD
2560 × 1440 is 3,686,400 pixels, or 3.69 megapixels: 1.78 times the 2,073,600 pixels of 1920 × 1080 and 44.4% of the 8,294,400 in 3840 × 2160. The 1920x1080 sheet covers the Full HD frame itself.
The 2.5K and 2.7K sizes cameras record
Action cameras and drones use "2.5K" and "2.7K" for at least four different frames: 2688 × 1512 (DJI), 2704 × 1520 (GoPro), 2720 × 1530 (some drones, per the Wikipedia 1440p list) and the 2560 × 1080 ultrawide. Two of the four, 2688 × 1512 and 2720 × 1530, reduce exactly to 16:9; GoPro's 2704 × 1520 is 169:95 and 2560 × 1080 is 64:27.
DJI 2.7K is 2688 × 1512, an exact 16:9 frame
The DJI Osmo Action 5 Pro specifications list 2.7K as 2688 × 1512 (16:9) and 2688 × 2016 (4:3). 2688 is 168 × 16 and 1512 is 168 × 9, so the frame is exactly 16:9 with 4,064,256 pixels, 1.96 times Full HD.
GoPro 2.7K is 2704 × 1520, a 169:95 frame slightly wider than 16:9
GoPro's 2.7K mode records 2704 × 1520 (GoPro camera tech specs, unlinked), which reduces to 169:95, or 1.7789, about 0.06% wider than 16:9. Scale it to 1921 × 1080 (1921.3 exact) and trim one column total, or 0.6 px per side, to land on 1920 × 1080.
2560 × 1080 is a 64:27 ultrawide, and why 2.7K exists at all
2560 × 1080 shares QHD's width but only 1,080 rows: 2,764,800 pixels in a 64:27 (2.37:1) shape marketed as 21:9, which belongs on the 4:3 sheet's 21:9 section. The 2.7K modes exist because 2688 and 2704 are about 1.4 times 1920, so a downscale to Full HD averages two source pixels into each output pixel and leaves room to stabilise at a fraction of 4K's storage cost.
What 4K resolution means: UHD 3840 × 2160 vs DCI 4096 × 2160
Consumer 4K is 3840 × 2160 (8,294,400 pixels, 16:9, square pixels), while cinema DCI 4K is a 4096 × 2160 container (8,847,360 pixels, 256:135 or about 1.90:1). Both keep 2,160 rows; they differ by 256 columns.
4K UHD is 3840 × 2160 under ITU-R BT.2020
Table 1 of ITU-R Recommendation BT.2020-2 defines ultra-high-definition television with a 16:9 picture aspect ratio, a pixel count of 3840 × 2160 or 7680 × 4320, and a 1:1 pixel aspect ratio. 3840 × 2160 is exactly twice 1920 × 1080 on each axis, so four Full HD frames tile it perfectly.
DCI 4K is a 4096 × 2160 container with flat and scope crops inside it
Section 4.3.1 of the DCI Digital Cinema System Specification v1.4.1 states that for a 4K distribution the DCDM container is 4096 × 2160, and for 2K it is 2048 × 1080. Films rarely fill the container: a 1.85:1 "flat" release is 3996 × 2160 and a 2.39:1 "scope" release is 4096 × 1716.
DCI 4K is 6.67% wider and holds 6.67% more pixels, not 12.5%
256 extra columns over 3,840 is 6.67% more width, and 8,847,360 divided by 8,294,400 is 1.0667, so the pixel gain is also 6.67%. The 12.5% figure that circulates online comes from dividing 256 by 2,048, the 2K width, and does not apply to 4K.
2.5K vs 4K: pixels, megapixels and how they scale
4K UHD holds 2.25 times the pixels of 2.5K QHD (8.29 MP against 3.69 MP) and is exactly 1.5 times larger on each axis, so a QHD frame upscaled to 4K has to invent 55.6% of its pixels, while a 4K frame downscaled to QHD keeps 44.4% of them.
QHD to 4K is exactly 1.5x; 1080p to QHD is a non-integer 1.333x
3840 ÷ 2560 and 2160 ÷ 1440 both equal 1.5, so every two QHD pixels become three UHD pixels on each axis, and 1920 × 1080 to 3840 × 2160 is an exact 2x that maps each source pixel to a 2 × 2 block. 1920 × 1080 to 2560 × 1440 is 1.333x (4/3), so the scaler has to blend, which is why 1080p content often looks softer on a QHD monitor than on a 4K one.
DCI 4K on a UHD screen: 256 px cut total (128 per edge) or a 3840 × 2025 letterbox
Showing a 4096 × 2160 file on a 3840 × 2160 display means cropping 256 columns total (128 per edge, 6.25% of the width total, 3.125% per edge) or scaling to 3840 × 2025 with 135 blank rows total (67.5 per edge, so a player picks 67 and 68). The aspect ratio calculator does the same crop-or-pad arithmetic for any pair of sizes.
File size follows pixel count
At the same codec and quality, a 4K UHD file needs roughly 2.25 times the bitrate of a QHD file and four times that of 1080p. The video bitrate calculator turns a resolution, frame rate and duration into a target bitrate and file size. The codec matters as much as the resolution, and the codec sheet explains how codecs change the bitrate a file needs.
Monitor resolution chart: 720p to 8K
The monitor resolution chart below lists 17 display sizes from 1280 × 720 to 7680 × 4320 with exact pixel counts, reduced aspect ratios and how many Full HD frames each holds. Nine rows are exactly 16:9; GoPro's 2704 × 1520 is a near-miss at 1.7789 and the DCI containers are 1.8963.
| Name | Width × height | Ratio | Megapixels | × Full HD |
|---|---|---|---|---|
| HD (720p) | 1280 × 720 | 16:9 | 0.92 | 0.444 |
| Full HD (1080p) | 1920 × 1080 | 16:9 | 2.07 | 1.000 |
| WUXGA | 1920 × 1200 | 8:5 (16:10) | 2.30 | 1.111 |
| DCI 2K | 2048 × 1080 | 256:135 | 2.21 | 1.067 |
| QWXGA | 2048 × 1152 | 16:9 | 2.36 | 1.138 |
| UW-FHD | 2560 × 1080 | 64:27 | 2.76 | 1.333 |
| QHD / 2.5K (1440p) | 2560 × 1440 | 16:9 | 3.69 | 1.778 |
| WQXGA | 2560 × 1600 | 8:5 (16:10) | 4.10 | 1.975 |
| 2.7K (DJI) | 2688 × 1512 | 16:9 | 4.06 | 1.960 |
| 2.7K (GoPro) | 2704 × 1520 | 169:95 | 4.11 | 1.982 |
| 3200 × 1800 (16:9 laptop panel) | 3200 × 1800 | 16:9 | 5.76 | 2.778 |
| UWQHD | 3440 × 1440 | 43:18 | 4.95 | 2.389 |
| 4K UHD (2160p) | 3840 × 2160 | 16:9 | 8.29 | 4.000 |
| DCI 4K | 4096 × 2160 | 256:135 | 8.85 | 4.267 |
| DQHD | 5120 × 1440 | 32:9 | 7.37 | 3.556 |
| 5K | 5120 × 2880 | 16:9 | 14.75 | 7.111 |
| 8K UHD (4320p) | 7680 × 4320 | 16:9 | 33.18 | 16.000 |
Portrait sizes are left out on purpose: the 3:4 portrait family is tabulated on the 3:4 aspect ratio sheet, and phone screens on the 9:16 resolution sheet.
Pixels per inch by screen size
Pixel density is the diagonal pixel count divided by the diagonal in inches, so the same resolution gets coarser as the panel grows. On 16:10 laptops, 2560 × 1600 is 227.0 ppi at 13.3 inches, 215.6 ppi at 14 inches and 188.7 ppi at 16 inches.
| Screen | 1920 × 1080 | 2560 × 1440 | 3840 × 2160 |
|---|---|---|---|
| 24-inch | 91.8 ppi | 122.4 ppi | 183.6 ppi |
| 27-inch | 81.6 ppi | 108.8 ppi | 163.2 ppi |
| 32-inch | 68.8 ppi | 91.8 ppi | 137.7 ppi |
| 55-inch TV | 40.0 ppi | 53.4 ppi | 80.1 ppi |
| 65-inch TV | 33.9 ppi | 45.2 ppi | 67.8 ppi |
Which AI models output 1K, 2K and 4K in Playcut
In Playcut, Veo 3.1 and Seedance 2.0 are the video models with a 4K tier, five more video models top out at 1080p or 720p, and the two Nano Banana image models render 1K, 2K or 4K while Grok Imagine images stop at 2K. None of Playcut's video providers publish per-ratio pixel sizes for 4K.
Video: two models reach 4K, the rest stop at 1080p or 720p
Veo 3.1 offers 720p, 1080p and 4K (the API value is 4k) at 16:9 or 9:16 only, and
Google's Veo documentation
pins both 1080p and 4K to 8-second clips. Seedance 2.0 offers 480p, 720p, 1080p and 4K across six ratios; its
documented 16:9 sizes are 864 × 480, 1248 × 704 and 1920 × 1088, with per-ratio pixels not published for 4K.
Wan 2.7 and HappyHorse 1.1 stop at 1080p, Grok Imagine Video (classic) and Imagine Video 1.5 (image-to-video only) at 720p, and Omni Flash renders 720p only.
Images: Nano Banana renders 1K, 2K and 4K; Grok Imagine stops at 2K
Nano Banana Pro and Nano Banana 2 accept 1K, 2K and 4K; at 1:1 those are 1024 × 1024, 2048 × 2048 and 4096 × 4096. At 16:9, Playcut's own table lists 1376 × 768, 2752 × 1536 and 5504 × 3072, a 43:24 grid about 0.8% wider than 16:9, since Google publishes no per-ratio table. Grok Imagine (image) offers 1K and 2K with no 4K tier; the image generator page lists every ratio per model.
What the 4K tier costs in credits
Veo 3.1 bills 160 credits per second at 720p and 1080p and 240 at 4K, so an 8-second 4K clip is 1,920 credits against 1,280 at 1080p. Seedance 2.0 bills 10, 21, 60 and 108 credits per second at 480p, 720p, 1080p and 4K; Nano Banana Pro is 67 credits at 1K or 2K and 84 at 4K. Each tier is selectable in Playcut's video generator before you render, and the pricing page lists how many credits each plan includes.
Should you work in 2.5K or 4K?
Pick 2.5K when the output is viewed at desktop size and pick 4K when you will crop, reframe, print or archive, because the 2.25x pixel budget only pays off if you use it. On a 27-inch monitor that is 109 ppi against 163 ppi, which is why 27-inch 4K panels are usually run at 150% scaling while QHD keeps text at 100%.
For video delivery: master at the size you crop from, deliver at the size the platform re-encodes to
Major platforms re-encode uploads, so the master should be the frame you crop and stabilise from, and the delivery file whichever ladder rung the platform keeps. The per-platform sizes are on the YouTube video size sheet and the social video spec sheet.
For AI generation: 4K when you need to punch in or print, 1080p or 1K otherwise
A 4K render lets you crop a 16:9 clip to 9:16 and still keep 1215 × 2160 pixels, or print a 3840 × 2160 still at 12.8 × 7.2 inches at 300 dpi; a QHD still prints at 8.53 × 4.8 inches. For a feed post or a preview, 1080p or 1K renders faster and costs fewer credits, and an upscaler can enlarge a keeper afterwards.
Gaming and resizing, in one line each
The best resolution for gaming is still the one most players run: in the August 2026 Steam Hardware Survey, 1920 × 1080 led with about 51% of primary displays, 2560 × 1440 was second at about 22%, and 3840 × 2160 sat near 5% (Steam Hardware & Software Survey, August 2026, store.steampowered.com/hwsurvey, unlinked). To change the resolution of an image without an editor, the image resizer scales or crops a still to any pixel size in the browser.
How to check what resolution a screen or file is
Read the pixel width and height from your display settings or the file's info panel, then divide width by height: 1.778 is 16:9, 1.6 is 16:10 and 1.896 is a DCI container. Windows lists the panel's native size as "Recommended" under Display settings and macOS shows it under Displays; scaling percentages change how large text looks, not how many pixels the panel has.
Get Info on macOS or Properties on Windows prints a file's dimensions. Where ffprobe is installed, the command below prints width, height and the declared display ratio; on files without a ratio flag the last field prints N/A, so divide the two numbers yourself.
ffprobe -v error -select_streams v:0 -show_entries stream=width,height,display_aspect_ratio -of csv=p=0 in.mp4A 2560 × 1440 file prints 2560,1440,16:9 and a 4096 × 2160 file prints 4096,2160,256:135. Paste either pair into the find-your-aspect-ratio guide if the division does not land on a ratio you recognise.