Theoria

Theoria is a very nice Android application for developers, designers and people who would like to learn new things.
You can download for free here or use the website version down.
Website version of the Android application Theoria
At the end of your life you will be judged from your love. (saint John from Cross)
Date and international time: People who works as developers or designers have to search various information and collaborate with people from all the world. So it is good to know the time.
Search: This area includes some search engines. DuckDuckGo is for people who do not like Google. And Google is for others. Wikipedia is used by beginners.
Dev: This section is for people who would like to learn programming. There are a lot of websites and documentations from the most used technologies and programming languages. If a person wants to learn programming, he/she needs to know more like one programming language. He/she needs to know databases, operating systems, computer network, frameworks, libraries, some IDE editor for easier work and much more.
Translate: A lot of content is in English language and all of the people do not know this language. Then you can use which is your favourite translator.
Sizes: Every developer and designer have to know some sizes of their creations.
Width x Height
Ads
Amazon ad - 300x250px
Billboard ad - 970x250px
Display ad - 300x600px
Facebook ad - 1080x1080px
Instagram ad - 1080x1350px
Instagram story ad - 1080x1920px
Large billboard ad - 1940x500px
Large rectangle ad - 300x600px
Leaderboard ad - 728x90px
LINE ads image (small) - 600x400px
LINE ads square image - 1080x1080px
LINE ads vertical video - 1080x1920px
LINE official account rich messages - 1040x1040px
Medium rectangle ad - 300x250px
Mobile banner ad - 320x50px
Mobile leaderboard tablet ad - 728x90px
Mobile medium rectangle ad - 300x250px
Mobile search results ad - 414x125px
Print ad - A4 (148x105mm)
Skyscraper ad - 160x600px
Snapchat ad - 1080x1920px
TikTok ad - 1080x1920px
Web banner - 1200x1000px
Yahoo Web Banner Ad - 1200x628px
YouTube display ad - 300x60px
YouTube video ad - 1920x1080px
Banners and Covers
Album cover - 750x750px
Blog graphic - 800x1200px
Blog header - 2240x1260px
Book cover - 1410x2250px
Cover page - A4 (210x297mm)
Ebook cover - 1600x2560px
Etsy shop banner - 1600x213px
Etsy shop cover - 1600x400px
Eventbrite header - 2160x1080px
Facebook event cover - 1200x1080px
Facebook group cover - 1640x856px
Facebook page cover - 820x312px
Facebook profile cover - 851x315px
Facebook shop cover - 1600x1200px
LinkedIn cover image - 1584x396px
Magazine - A4 (210x297mm)
Podcast cover - 3000x3000px
Print ad - A6 (148x105mm)
Reddit cover - 1920x256px
Tumbl banner - 3000x1055px
Twitch overlay - 1920x1080px
Web banner - 1200x1000px
X (Twitter) header - 1500x500px
YouTube banner - 2560x1440px
Blog and websites
Blog graphic - 800x1200px
Blog header - 2240x1260px
Etsy shop banner - 1600x213px
Etsy shop cover - 1600x400px
LinkedIn blog post - 1200x628px
Brand
Business card - 85x55mm
Email header - 600x200px
Letterhead - A4 (210x297mm)
Logo - 500x500px
Media kit - A4 (210x297mm)
Document
A0 - 1189x841mm
A1 - 841x594mm
A2 - 594x420mm
A3 - 420x297mm
A4 - 297x210mm
A5 - 210x148mm
A6 - 148x105mm
US Letter - 11x8.5in
Legal - 14x8.5in
Tabloid - 17x11in
Document-Business
A3 landscape - 408x297mm
A3 portrait - 297x420mm
Ad landscape - 297x210mm
Ad portrait - 210x297mm
A5 landscape - 210x148mm
A5 portrait - 148x210mm
Brochure - A4 (297x210mm)
Business card - 85x55mm
Card - A5 (148x210mm)
Certificate - A4 (297x210mm)
Cover page - A4 (210x297mm)
Divider page - A4 (210x297)
Ebook - A4 (210x297mm)
Flyer - A4 (210x297mm)
Gift certificate - 220x110mm
Infographic - 800x2000px
Invitation - A5 (148x210mm)
Invoice - A4 (210x297)
Leaflet - A4 (210x297mm)
Letter - A4 (210x297mm)
Letterhead - A4 (210x297mm)
Magazine - A4 (210x297mm)
Memo - A4 (210x297mm)
Menu - A5 (148x210mm)
Name tag - 90x76mm
Newsletter - A4 (210x297mm)
Pamphlet - A4 (210x297mm)
Poster - A3 (297x420mm)
Presentation - 1920x1080px
Program - A4 (210x297mm)
Proposal - A4 (210x297mm)
Report - A4 (210x297mm)
Table of contents - A4 (210x297mm)
Document-Education
A3 landscape - 420x297mm
A3 portrait - 297x420mm
A4 landscape - 297x210mm
A4 portrait - 210x297mm
A5 landscape - 210x148mm
A5 portrait - 148x210mm
Class schedule - A4 (297x210mm)
Ebook - A4 (210x297mm)
Flashcard - A6 (148x105mm)
Flashcard sheet - A4 (210x297mm)
Google classroom banner - 1000x250px
Graphic organizer - A4 (210x297mm)
Infographic - 800x2000px
Lesson plan - A4 (210x297mm)
Newsletter - A4 (210x297mm)
Poster - A3 (297x420mm)
Report card - A4 (210x297mm)
Resume - A4 (210x297mm)
Rubric - A4 (210x297mm)
Worksheet - A4 (210x297mm)
Document-Personal
A3 landscape - 420x297mm
A3 portrait - 297x420mm
A4 landscape - 297x210mm
A4 portrait - 210x297mm
A5 landscape - 210x148mm
A5 portrait - 148x210mm
Bookmark - 51x152mm
Calendar - A4 (210x297mm)
Card - A5 (148x210mm)
Certificate - A4 (297x210mm)
Comic strip - A4 (297x210mm)
Gift tag - 89x51mm
Checklist - A4 (210x297mm)
Invitation - A5 (148x210mm)
Journal - A4 (210x297mm)
Label sheet - A4 (210x297mm)
Magazine - A4 (210x297mm)
Name tag - 90x76mm
Place card - 1050x1020px
Planner - A4 (210x297mm)
Postcard - 148x100mm
Poster - A3 (297x420mm)
Recipe card - 100x150mm
Resume - A4 (210x297mm)
Facebook
ad - 1080x1080px
event cover - 1200x630px
group cover - 1640x856px
page cover - 820x312px
post - 1080x1080px
profile cover - 851x315px
story - 1080x1920
Icon
iOS App - 1024x1024px
Mac App - 1024x1024px
Android App - 512x512px
Instagram
ad - 1080x1350px
carousel - 1080x1080px
landscape post - 1080x566px
portrait post - 1080x1350px
reel - 1080x1920px
square post - 1080x1080px
story - 1080x1920px
story ad - 1080x1920
LinkedIn
blog post - 1200x628px
company logo - 400x400px
cover image - 1584x396px
personal profile image - 400x400px
post - 1080x1080px
video - 1080x1920px
Paper
A0 - 1189x841mm
A1 - 841x594mm
A2 - 594x420mm
A3 - 420x297mm
A4 - 297x210mm
A5 - 210x148mm
A6 - 148x105mm
US Letter - 11x8.5in
Legal - 14x8.5in
Tabloid - 17x11in
Photo
Album cover - 750x750px
Book cover - 1400x2500px
Calendar - A4 (210x297mm)
Desktop wallpaper - 1920x1080px
Eventbrite header - 2160x1080px
Facebook profile cover - 651x315px
ID card - A7 (74x105mm)
LinkedIn cover image - 1584x396px
Logo - 500x500px
Meme - 1200x1200px
Phone wallpaper - 1080x1920px
Photo book - A4 (210x297mm)
Playlist cover - 3000x3000px
Podcast cover - 3000x3000px
Postcard - 148x100px
YouTube profile photo - 800x800px
Zoom background - 1920x1080px
Pinterest
idea pin - 1080x1920px
post - 1000x1500px
square - 600x600px
vertical post - 600x900px
Presentations
Concept map - A4 (210x297mm)
Graph - 1920x1080px
Infographic - 800x2000px
Mindmap - 1024x768
Presentation - 1920x1080px
Promotionals material
Bottle laberl - 100x100mm
Brochure - A4 (297x210mm)
Card - A5 (148x210mm)
Certificate - A4 (297x210mm)
Coupon - A4 (210x297mm)
Flyer - A4 (210x297mm)
Gift certificate - 220x110mm
Gift tag - 89x51mm
Invitation - A5 (148x210mm)
Magazine - A4 (210x297mm)
Menu - A5 (148x210mm)
Mug - 84x84mm
Newsletter - A4 (210x297mm)
Online newsletter
Postcard - 148x100mm
Poster - A3 (297x420mm)
Print banner - 120x60cm
Program - A4 (210x297mm)
Ticket - 150x50mm
Tshirt - 254x305mm
Resolution
720P (HD) - 1280x720px
1080P (Full HD) - 1920x1080px
1440P (2K) - 2560x1440px
Ultra HD (4K) - 3840x2160px
Standard - 1024x768px
240P (SD) - 426x240px
144P (2K) - 256x144px
5K - 5120x2880px
6K - 6144x3160px
8K - 7680x4320px
TikTok
ad - 1080x1350px
ad - 1080x1920px
video - 1080x1920px
Video
mobile video - 1080x1920px
video - 1920x1080px
Facebook story - 1080x1920px
Instagram reel - 1080x1920px
Instagram square post - 1080x1080px
Instagram story - 1080x1920px
Instagram story ad - 1080x1920px
LINE ads square image - 1080x1080px
LINE ads vertical video - 1080x1920px
LinkedIn video - 1080x1920px
Pinterest idea pin - 1080x1920px
TikTok ad - 1080x1920px
TikTok video - 1080xx1920px
X (Twitter) video - 1920x1080px
YouTube shorts - 1080x1920px
YouTube video - 1920x1080px
YouTube video ad - 1920x1080px
X (Twitter)
header - 1500x500px
post - 1200x675px
video - 1920x1080px
YouTube
banner - 2560x1440px
display ad - 300x60px
profile photo - 800x800px
shorts - 1080x1920px
thumbnail - 1280x720px
video - 1920x1080px
video ad - 1920x1080px