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38 guides
What compression actually throws away, why the destination decides the setting, and how to hit a hard size limit on the first try.
7 min readWhere the 10 MB limit comes from, the bitrate arithmetic behind it, and how Target Size mode lands within a few percent of it — free, in your browser.
6 min readWhere 20 MB upload limits come from, how much video the math allows at each duration, and how Target Size mode lands within about 3% on one pass.
6 min readWhy a 25 MB email limit really means 20 MB on disk, and how a two-pass target-size encode lands under it on the first try.
6 min readDiscord caps free uploads at 20 MB. Hit that number on the first try: pick the Discord target and a two-pass encode lands within about 3%.
6 min readGmail and Outlook stop at 25 MB, and encoding eats a third of that. How to pick a target size that actually arrives on the first try.
7 min readWhat image compression actually removes, why a PNG behaves nothing like a JPEG, and how to pick a setting you will not regret.
6 min readThe four formats that matter, what each is actually for, and the one conversion you should never make.
8 min readResize a photo without stretching or squashing it: set one dimension, keep the aspect ratio, and let the resizer do the math. Free, no sign-up.
6 min readWhat actually takes up space in a PDF, why a scan compresses 90% and a text document 5%, and how to choose a setting that still prints well.
6 min readWhat Deflate levels 0–9 really change, how to get a ZIP under a 10 MB or 25 MB limit, and why text archives shrink a lot while photo ZIPs barely move.
9 min readLearn to precisely resize images for social media profiles, banners, and web layouts using CompressKits' free online Image Resizer tool.
15 min readLearn how to compress video for WhatsApp status and sharing without losing quality. CompressKits' free online tool guides you to the right settings for perfect uploads.
6 min readLearn to compress videos for smaller files without visible quality loss. This guide details optimal settings, codecs, and an iterative workflow using our online tool.
6 min readLearn how to significantly reduce video file size for website backgrounds and banners without sacrificing visual impact, ensuring fast load times and a seamless user
6 min read
Learn the precise settings to compress video for Instagram Reels, Stories, and posts, ensuring optimal quality and quick uploads.
6 min readLearn to shrink large iPhone videos, like 4K .MOV files, for easy sharing via email or messages without excessive quality loss. Get concrete steps and ideal settings.
6 min readLearn to effectively downscale your 4K video to 1080p, drastically reducing file size while maintaining visual quality for sharing and uploads.
6 min readLearn how to compress a PDF to under 2 MB for job, visa, and portal uploads using the right settings, balancing file size with visual quality for compliance.
6 min readLearn the practical techniques to make a ZIP file smaller, including pre-compression strategies for different file types and understanding the real limits of ZIP
7 min readBitrate explained in plain language: what 320, 192, 128 and 64 kbps actually sound like, when mono is fine, and how to shrink an MP3 without audible damage.
6 min readWhy audio files fail to send on WhatsApp, the difference between sending as audio and as document, and the compression settings that keep recordings clear at chat size.
6 min readEmail attachment limits, the 33% encoding overhead nobody mentions, and why 64 kbps mono turns an hour of lecture audio into a file any inbox accepts.
6 min readThe practical difference between H.264 and H.265 (HEVC): real size savings, device compatibility, encode speed, and a simple rule for choosing between them.
7 min readKeep the full 4K resolution and still cut 60–90% of the file: why camera files are so inflated, what H.265 changes, and the settings that stay visually lossless.
7 min readHEIC is the format iPhones save photos in — half the size of JPG, and famously unopenable elsewhere. What it is, why Windows balks, and the fastest fixes.
6 min readThe camera-roll-to-accepted-upload workflow: convert HEIC to JPG in the browser, fix orientation, strip location data, and meet the size caps portals enforce.
6 min readWhen a portal rejects your iPhone photo twice — once for HEIC, once for size — fixing the errors one at a time is the slow way. The one-step fix, explained.
6 min readThe fields every payable invoice needs — numbering, dates, line items, tax, payment details — and the omissions that quietly delay your money.
7 min readOne asks for money, the other proves it arrived. The real differences between invoices and receipts, what each must contain, and which one to issue when.
5 min readDiscover the real reasons your ZIP file isn't getting smaller. This guide breaks down common culprits like pre-compressed data, file overhead, and data entropy, offering
7 min readSending large ZIP files via email hits size limits fast. Learn the practical, step-by-step workflow to pre-compress individual files effectively before zipping them,
6 min readLearn to quickly reduce video file sizes on your iPhone or Android phone using CompressKits.
6 min readLearn how to compress images for email effectively, fitting large photos within attachment limits for Gmail, Outlook, and others.
7 min readLearn to convert your JPEGs to WebP for significantly smaller image files without noticeable quality loss.
7 min readLearn to effectively compress product images for your e-commerce store. Improve page load speeds, boost SEO, and enhance conversion rates with optimized visuals.
6 min read