Calculator
What the Twitter Header Maker does
Twitter Header Maker: outputs exactly 1500x500 px, the size X/Twitter uses for profile headers. Everything runs in your browser and the file is never uploaded.
The Twitter Header Maker generates the file you choose without uploading it anywhere. Processing is local, so speed depends on your machine rather than someone else’s server load.
It is mostly used by someone converting between formats. Sending a photo to a server just to resize it is more exposure than the task deserves.
Everything happens inside this page. Nothing you type is sent to a server, and there is nothing for us to store.
Further down the page: what each field expects, how the result is derived, and one example worked from the defaults.
What do the Twitter Header Maker fields mean?
The Twitter Header Maker uses 3 inputs. The form opens pre-filled, so the fastest way in is usually to overwrite the one field you actually care about.
| Field | What to enter | Default |
|---|---|---|
| Image file | stays on your device | none |
| Export as | choose from PNG, JPEG or WebP | JPEG |
| Quality % | accepts 10 to 100 | 90 |
How does the Twitter Header Maker work?
Each output is derived from the inputs above in a single pass; there is no hidden state carried between runs, so the same inputs always give the same generated output.
Checks happen up front, so errors surface next to the form instead of hiding in the output.
What a typical run looks like
You provide: Image file, Export as and Quality %
What happens: the file is read into memory by your browser, processed locally, and offered back as a download. It is never uploaded.
You get back: the result as a file you can save, with a one-line summary beside it.
Nothing queues behind a server, so the wait is your device working, and the size limit is set by memory rather than by an upload cap.
X / Twitter headers sizes
The header is a 3:1 banner, which is an unusually wide ratio, and the profile picture overlaps its lower-left corner. Both facts constrain the design more than the pixel dimensions do.
| Use | Size | Ratio |
|---|---|---|
| Header / banner | 1500 × 500 | 3:1 |
| Profile picture | 400 × 400 | 1:1 |
| In-stream image | 1600 × 900 | 16:9 |
| Summary card image | 1200 × 628 | 1.91:1 |
Worth knowing
- The profile picture sits over the lower-left of the header and is roughly 200px across at display size. Keep that corner empty.
- The header crops vertically on narrow viewports: centre anything important.
- File size limit is 2 MB for images, 5 MB for GIFs.
- In-stream images are cropped to 16:9 in the timeline but shown in full when opened.
Platforms revise their published specifications from time to time. Where a ratio and a pixel size conflict, match the ratio — every platform downscales an oversized image, but none of them will fix a wrong shape except by cropping it.
How to use it
- Choose your file under Image file, or drag it onto the drop area.
- Pick a value for Export as: the options are PNG, JPEG or WebP.
- Fill in Quality % (10 to 100).
- Press Create.
- The results panel then shows Status.
- Both Copy Link and Print capture the current state, so pick whichever suits how you file things.
What this tool does not do
- EXIF metadata may be dropped during processing, which is usually desirable but worth knowing.
- Re-encoding a lossy format such as JPEG always loses some detail, even at maximum quality.
- The result reflects the moment you ran it; anything that changes over time is not tracked.
- Check that each figure is in the unit the label asks for; that is the most common source of a wrong result.
- Because everything runs locally, processing speed depends on your device rather than our servers.
Frequently asked questions
3 things: Image file, Export as and Quality %. A starting value is in place for each, which makes it easy to isolate the effect of a single variable.
Quality % accepts 10 to 100. Values outside that range are rejected with a message naming the field, rather than producing something that looks valid but is not.
Your file stays on your machine. Nothing is transmitted, stored or queued for processing elsewhere.
It costs nothing, and there is no limit on repeat use.
It implements the published definition directly, without shortcuts or approximations.