Megabyte limits come from mail services, marketplaces, job portals and passport sites rather than exam forms, and the files that trip them are ordinary phone photos: a 12-megapixel shot weighs 3 to 8 MB, and a handful in one message adds up quickly. To reduce image size in MB, use the box on this page, which already reads 1 with MB selected, and write 2, 5 or 1.5 over it when your field names a different figure.
A megabyte is 1,024 KB here, and the figure you type is turned into bytes before the search begins. The compressor then hunts for the highest JPG quality that keeps the photo beneath that line. Measured on 12-megapixel photos, it ends with every pixel still in place at 1 MB and above.
Before and after
3600 × 2396 px3.70 MBJPG
3600 × 2396 px932 KBJPG
This photo was 3.70 MB. With the limit set to 1.00 MB, it came out at 932 KB, which is 75% smaller.
The pixel size stayed at 3600 × 2396 px. Only the JPG quality was lowered.
The numbers are from a real run of the tool above. The pictures here are smaller previews of the actual files.
How to use it
- Find the figure in the error message or beside the upload button. Leave the box at 1 for a 1 MB rule, or type 2, 4, 10 or 1.5 to match it.
- Add the photo. Camera JPGs, iPhone HEIC files, PNG screenshots and WebP files are read; one that is lighter than the figure to begin with is flagged as already fitting, with the original offered back.
- Press Compress and read the card: input weight in MB, output weight, the width and height kept, and the quality the search settled on.
- Download the JPG and attach or upload it. Keep the original, because the copy has fewer bytes and no camera data.
Where megabyte caps come from
Mail came first. Google’s help page for Gmail states that for personal accounts the limit is 25 MB, and that an attachment past it is removed and replaced by a Google Drive link. Photos in one message share that allowance, so five 5 MB originals fail where five 1 MB copies pass.
Rules written in megabytes are usually generous ceilings, and official ones often pair the ceiling with a floor. HM Passport Office asks for a digital photo of “at least 50KB and no more than 10MB”. Immigration, Refugees and Citizenship Canada wants the online renewal photo “Between 200 KB and 5 MB”. LinkedIn’s help page gives a profile photo a “Maximum file size 8MB”. Job sites and marketplaces mostly cap at 2, 5 or 10 MB.
Type the figure as printed: “under” and “less than” mean the ceiling itself. A floor goes into the minimum field after ticking the box. Both fields share one unit, so a 200 KB to 5 MB rule is entered as 5 and 0.2 with MB selected, or as 5120 and 200 after flipping the chip to KB.
What a 12-megapixel photo keeps at 2 MB, 1 MB and 500 KB
We ran four 4032 × 3024 photos through this engine, saved at quality 95 so they weighed 1.2 to 3.7 MB like camera output. At 2 MB every one kept its full width and height at a quality between 88 and 95. At 1.5 MB the setting sat between 81 and 90, at 1 MB between 69 and 93, and even at 500 KB all four stayed at 4032 × 3024, the busiest scene dropping to quality 41 and the plainest holding 83.
Megabyte targets, then, cost quality rather than pixels. A document on a desk or a face against a wall barely moves; leaves or gravel fall furthest, and near quality 70 or lower fine texture smears when you zoom in. Two megabytes is the roomy choice wherever a rule allows it, 1 MB is still comfortable, and 500 KB is where busy photos start to show the squeeze.
Your own photo will shift these figures slightly; the card prints the quality used. Above about 16 million pixels, a 48-megapixel shot is reduced to that count as it loads, and a notice says so.
Decimals, the KB readout and when to resize instead
The box takes decimals: 1.5 sets a ceiling of 1,572,864 bytes and 4 gives 4,194,304. A rule written in kilobytes is better typed that way after flipping the chip, since a cap of 1000 KB is 24 KB stricter than the megabyte counted here. Under 1,024 KB the result card prints kilobytes, so a 1 MB run reads as about 1000 KB rather than 0.98 MB: the same file in a stricter unit.
Resize first when the picture will be shown small, such as a listing thumbnail, or when the rule names a pixel count as well as a weight. Bringing a 4032 × 3024 photo down to 2000 pixels wide removes three quarters of its pixels and usually lands under 1 MB at a high quality on its own.
Frequently asked questions
- Can I reduce image size in MB to KB on this page?
- Yes. Tap KB on the unit chip and type the figure, for example 100 for a 100 KB field. The engine is the same as on the kilobyte pages.
- How do I reduce photo size in MB on an iPhone?
- In Safari, tap the drop zone and choose from your photo library. A HEIC original is decoded on the spot, saved as a JPG under your figure, and ready for Mail or Files.
- Will going from 5 MB to 1 MB lose quality?
- Some, but not pixels. In our runs a 12-megapixel photo kept its full 4032 × 3024 at 1 MB with the quality between roughly 70 and 90, and the loss showed only when zoomed into fine texture. If you can see it and the rule allows 2 MB, type 2.
- Can it reduce a PDF or a video in MB?
- No. It reads image files and writes a JPG. PDF files have a page of their own, and video is not handled.
- Does a 6 MB PNG screenshot stay a PNG?
- It leaves as a JPG, because the size search works on JPG quality. A PNG of a phone screen that size usually drops to a few hundred KB with the text still readable, and any transparent area is filled with white.