Resize an Image to 40KB on Android or iPhone

To resize an image to 40 KB, open the photo in ResizePing on Android or iPhone, set Mode to Target size and type 40 in the Target (KB) field. Some upload forms ask for 40 KB. It sits between 30 KB and 50 KB.

Need a photo at this size? ResizePing resizes photos to exact dimensions or a file size on iPhone and Android. Get it on Google Play or the App Store.

Steps

Android: Target size mode with the Target (KB) field. This capture shows 100; type 40.

iPhone: the same Target (KB) field. This capture shows 100; type 40.

Open ResizePing and choose the photo, or several photos.
Change Mode to Target size.
Enter 40 in Target (KB). Type a whole number.
Choose JPG, PNG or WEBP to match what the portal lists. Location data is stripped by default.
Check the Projected size shown for each photo.
Tap Run and look at the saved file's size before uploading.

Your files never leave your device.

Landing just under 40 KB

The projected size is an estimate, so the saved file can differ from it. If the portal's limit is strict, type 38 in Target (KB) instead of 40 and check the real size of the result before you upload.

If 40 KB is out of reach

ResizePing warns you when 40 KB can't be reached. Then lower the resolution with Dimensions or Percent, run it, and set Target size to 40 on the smaller result. If the portal allows more room, pick a larger limit from the sizes below.

40 KB vs other sizes

20 KB: tighter: Resize an Image to 20 KB on Android or iPhone.
30 KB: How to Resize a Photo to 30 KB for an Exam or Job Form.
50 KB: more room: Resize an Image to 50 KB on Android or iPhone.
100 KB: more room: How to Reduce Photo Size to 100 KB on iPhone and Android.
150 KB: Resize an Image to 150 KB on Android or iPhone.
Not sure which limit applies: Resize an Image to 20 KB or 50 KB.

What to know

You can process one photo or a batch.
Android and iPhone both have Target size mode.

FAQ

What if the form says "up to 40 KB"?

Type 40, or a little lower such as 38, in Target (KB). Then check the real size of the saved file, because the projected size is only an estimate.

Why is the result different from the projected size?

The projected size is an estimate shown before you run. The saved file's size is the one that counts, so read it before you upload.

Can I do several photos at once?

Yes. You can process one photo or a batch, and each photo shows its own projected size.

Which format should I choose?

The one the portal asks for. ResizePing offers JPG, PNG and WEBP.

Do Android and iPhone work the same way?

Yes. Both have Target size mode with the Target (KB) field and a projected size.

On a computer

On a computer instead? Ping Tools Lab has a browser tool: Resize Image to 40 KB.