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Converters8 file families · 44 direct conversions
What changes in a conversionarrow_forward
image57 formats
Image Converterarrow_forwardPhotos, screenshots, icons and graphics. Change format, cut size for the web, or rescue iPhone HEIC photos.
swap_horizPopularall 7
HEIC → JPGAVIF → JPGBMP → JPG
movie30 formats
Video Converterarrow_forwardScreen recordings, phone clips and exports. Re-wrap or re-encode for any player, or pull audio and GIFs out.
swap_horizPopularall 10
Video → GIFAVI → MP4GIF → MP4
graphic_eq42 formats
Audio Converterarrow_forwardVoice memos, podcasts and music. Go lossless for editing or compact for sharing, without touching quality twice.
swap_horizPopularall 7
AAC → MP3FLAC → M4AFLAC → MP3
description28 formats
Document Converterarrow_forwardContracts, spreadsheets and reports. Make PDFs editable, lock Word files into PDFs, or pull clean data out of tables.
swap_horizPopularall 8
Image → PDFPDF → JPGPresentation Converter
menu_book11 formats
Ebook Converterarrow_forwardBooks and long reads. Move titles between Kindle, Kobo and Apple Books, or read them right here in the browser.
swap_horizPopularall 0
folder_zip16 formats
Archive Converterarrow_forwardBundles of files. Open RAR and 7Z without installing anything, or repack into ZIP so anyone can open it.
swap_horizPopularall 4
RAR → ZIP7Z → ZIPTAR.GZ → ZIP
font_download8 formats
Font Converterarrow_forwardTypefaces for design and the web. Turn desktop fonts into fast WOFF2 for sites, or back into TTF for apps.
swap_horizPopularall 4
TTF → WOFF2OTF → TTFWOFF2 → TTF
slideshow10 formats
Presentation Converterarrow_forwardDecks from PowerPoint, Keynote and Google Slides. Swap between them or flatten into a PDF anyone can open.
swap_horizPopularall 4
PPTX → PDFKEY → PPTXPPT → PPTX
Compressors8 file types · same format, smaller fileAlso:GIF Compressor·SVG Optimizer
How compression worksarrow_forward
imagearrow_forward
Image CompressorHit a KB target with measured SSIM
targetKB target or quality
JPGPNGWebPGIF
moviearrow_forward
Video CompressorFit a size limit with corrective passes
targetMB limit or preset
MP4MOVMKVAVI
graphic_eqarrow_forward
Audio CompressorBitrate against the measured cut-off
target32-320 kbps
MP3WAVFLACAAC
descriptionarrow_forward
Document CompressorResample scans, recompress streams
targetImage dpi
PDFDOCXODT
co_presentarrow_forward
Presentation CompressorShrink the photos and media inside slides
targetImage size in slides
PPTXPPTODP
menu_bookarrow_forward
Ebook CompressorSmaller EPUBs without losing chapters
targetImage quality
EPUBMOBIAZW3
folder_ziparrow_forward
Archive CompressorPack files at the best ratio
targetMethod and level
ZIP7ZTARGZ
text_fieldsarrow_forward
Font CompressorWeb-ready fonts for fast loading
targetOutput and subset
TTFOTFWOFFWOFF2
Tool hubs9 hubs · every tool, grouped, with an inspector on each
imageImage toolsEdit, crop, resize, redact and inspect photoscodec bake-offarrow_forwardmovieVideo toolsTrim, edit, compress and turn clips into GIFscontainer inspectorarrow_forwardgraphic_eqAudio toolsClip, join, record, mix and measure loudnessLUFS meterarrow_forwardpicture_as_pdfPDF toolsMerge, split, sign, protect and watermark PDFsstructure inspectorarrow_forwarddescriptionDocument toolsWord, Excel and CSV files, read down to the XMLhidden-data checkarrow_forwardmenu_bookEbook toolsEPUB, MOBI and comics checked and convertedreflow labarrow_forwardfolder_zipArchive toolsOpen, check and rebuild ZIP, TAR and 7Z safelysafety inspectorarrow_forwarddata_objectDeveloper toolsJSON, Base64, regex, hashes, JWT, colour and DNS20+ toolsarrow_forwardcalculateCalculatorsInterest, loans, VAT, dates, percentages and paceexact mathsarrow_forward
REFERENCEdictionaryFormats explainedWhat each format is forarrow_forwardschoolCore conceptsCodecs, containers, compressionarrow_forwardmemoryHow processing worksWhat happens to your filearrow_forward
GUIDESchecklistHow-to guidesStep-by-step walkthroughsarrow_forwarddevicesPlatform guidesTips for iPhone, Windows, Macarrow_forwardcompareComparisonsTwo formats measured side by sidearrow_forward
newspaperBlogNews, release notes and deep divesarrow_forward
lightbulbpopular comparisonJPG vs PNG: which one should this picture be?Measured on real photos, logos and screenshots, with a rule you can apply in a second.Read the comparisonarrow_forward
platform guides / wordpress

How to Optimize Images for WordPress

You upload one photo.
WordPress writes several.

On upload, WordPress core makes a copy at every registered size it can fit, and since 5.3 it scales anything over 2560 px down to a "-scaled" copy that pages use instead of your original. This page runs the same rules (wp_get_registered_image_subsizes, big_image_size_threshold, JPEG quality 82) in your browser and writes the real files.

4032×3024 camera JPEG1600×900 banner
wp-content/uploads/2026/10/resizing…
SRCSET

Which of those files does a visitor download?

When you insert the image, WordPress writes a srcset listing every copy with the same shape (the square thumbnail is left out) up to 2048 px, plus a sizes attribute. The browser does the choosing. Move the sliders to see what a phone, a laptop or a 4K screen fetches.

Inserted asMediumLargeFull size
Pixel density1×1.5×2×3×
The image fills 1024 CSS px; at 2× that needs 2048 device pixels (red mark). The browser takes the smallest file at least that wide: IMG_4512-2048x1536.jpg, 57 KB. Copies wider than 2048 px are never listed, so the 2560 px file is only used by "Full size" links.
…
Your browser, right nowLoading the generated files into a real img element…

Image formats in WordPress core

formatsincewhat core doesthis browser
JPEG1.0sub-sizes at quality 82; EXIF orientation applied on upload since 5.3can encode
PNG1.0sub-sizes stay PNG; no lossy compressioncan encode
GIF1.0sub-sizes are single still frames; only the original animatesn/a
WebP5.8uploads and sub-sizes, if the server’s GD or Imagick supports itcan encode
AVIF6.5uploads and sub-sizes, server support permittingdecode only
HEIC6.7converted to JPEG on upload when Imagick can read itn/a
SVGnot in coreblocked by upload_mimes; needs a plugin that sanitises scriptsdecodes in img
Sources: WordPress core wp-includes/media.php (add_image_size defaults, wp_calculate_image_srcset, max_srcset_image_width 2048), wp-admin/includes/image.php (big_image_size_threshold 2560, wp_create_image_subsizes), WP_Image_Editor default quality 82, make.wordpress.org/core release notes for 5.3, 5.8, 6.5 and 6.7. Server support depends on the host's GD or Imagick build; the right column tests your browser's encoder.
photo_size_select_largeImage resizerResize to 2560 px yourself so WordPress keeps your exact file.4032 px → 2560 pxcompressImage compressorCompress before upload; WordPress re-encodes every size at 82.3.4 MB → 780 KBlocation_offEXIF viewerCore keeps EXIF in the original file; check it first.IMG_4512.jpg → no GPSmailEmail guideSize limits when sending the same photo by email.19 MB → 25.6 MB email