On comparing iPad apps with iPhone equivalents, one thing rapidly becomes clear: apps for Apple's tablet are pricier (on an already pricey device).
Many of the best free iPhone apps cost $.99 or more in their iPad incarnations, and the quality level of what's still free is often sketchy. But among the mediocre, lie rare gems - iPad apps that are so good you won't believe they're still free.
Of those we unearthed, here is our pick of the best free iPad apps.
Note that apps marked "universal" will run on your iPad and iPhone, optimizing themselves accordingly.
For a mix of free and paid apps, check out our amazing Best iPad apps chart.
1. AccuWeather for iPad
Happily, AccuWeather also proves to be a decent - if quirky - weather app. The interface is odd (but fun) and there's a "lifestyle" page that determines how your current local conditions might affect over 20 activities, including dog walking and stargazing.
2. Facebook (universal)
The social networking giant has gone back-and-forth with its mobile apps, finally settling on this smart, native implementation. Much like the slightly simpler iPhone equivalent, Facebook on iPad is such that you won't want to use the comparatively clunky website again for seeing which of your friends really shouldn't have internet access after midnight.
3. Air Video Free (universal)
Despite naysayers whining about the iPad screen's 4:3 aspect ratio, it's a decent device for watching video, although it lacks storage for housing large video collections. Air Video enables you to stream video (converting it on-the-fly, if necessary) from your Mac or PC. The main limitation of the free version is that it only shows a few items (randomly selected) from each folder or playlist.
4. Beatwave (universal)
Beatwave is a simplified Tenori-On-style synth which enables you to rapidly build pleasing melodies by prodding a grid. Multiple layers and various instruments provide scope for complex compositions, and you can save sessions or, handily, store and share compositions via email. You can also buy more instruments via in-app purchases.
5. Bloomberg for iPad
It used to boast an eye-searing white-and-orange-on-black color scheme that was a little like being repeatedly punched in the eyes, but now Bloomberg has grown up, discovered a palette (a subtler, serious "things on black," for the most part), and has subsequently become a much more usable business news and stocks app.
6. Comics (universal)
On the iPhone, Comics is innovative, but zooming each panel and constantly rotating your device gets old fast. By contrast, the iPad's screen is big enough to display an entire page without the need to zoom or scroll. And with dozens of free comics available via the bundled store, comic book fans should lap this app up.
7. Dictionary.com - Dictionary & Thesaurus - for iPad
We approached Dictionary with skepticism, since most free dictionary apps are sluggish interfaces to websites. That's certainly what this looks like, but it works offline, providing speedy access to over two million words and definitions. The app's search is also reassuringly fast.
8. Dropbox (universal)
Dropbox is a great service for syncing documents across multiple devices. The iPad client works like the iPhone one (hardly surprising, since this is a universal app), enabling you to preview many file types and store those marked as favorites locally.
9. Evernote (universal)
Like Dropbox, Evernote (a free online service for saving ideas - text documents, images and web clips - that you can then access from multiple devices) works the same way on the iPad as it does on the iPhone. It benefits from the iPad's larger screen, which enables you to see and navigate your stored snippets more easily.
10. YouTube (universal)
When the YouTube app presumably became a victim of the ongoing and increasingly tedious Apple/Google spat, there were concerns Google wouldn't respond. Those turned out to be unfounded, because here's yet another nicely designed Google-created app for iOS. The interface is specifically tuned for the iPad, and AirPlay enables you to fire videos at an Apple TV.
Feedly is another news app, that pushes content to your iPad. Instead of having to hunt down for news, Feedly uses RSS to aggregate the contents of the news sites and blogs you like and deliver them as a fast mobile-optimized experience.
12. iBooks (universal)
Going head-to-head with Kindle, iBooks is a decent ebook reader, backed by the iBookstore. As you'd expect from Apple, the interface is polished and usable, with handy cross-device bookmark syncing, highlighting, and various display options. It's also a capable PDF reader, for your digital magazine collection.
Unless you have the perfect eye for light, color and composition, 99% of the time your photos will look a little flat. It may look a little weird when people use their iPads to take photos, but it happens and that means a good photo editing app is needed.
Snapseed is great for your iPad pics, as it will help give your flat photos a little more punch and bite, or it can mellow out a scene and give you some interesting tones and textures.
14. Kindle (universal)
Amazon's Kindle iPad app for reading myriad books available at the Kindle Store is a little workmanlike, and doesn't match the coherence of iBooks (you buy titles in Safari and "sync" purchases via Kindle). However, Kindle's fine for reading, and you get options to optimize your experience (including the ability to kill the page-turn animation and amend the page background to a pleasant sepia tone).
15. Movies by Flixter (universal)
One for film buffs, Movies figures out where you are and tells you what's showing in your local cinemas - or you can pick a film and it'll tell you where and when it's on. The app is functionally identical on iPad and iPhone, but again the extra screen space improves the experience.
16. PaperDesk Lite for iPad
Effectively a souped-up digital notepad, PaperDesk Lite for iPad enables you to combine typed words, scribbles and audio recordings in user-defined notebooks. Be mindful, though, that this free version restricts you to three notebooks, each of which can only have three pages, and there are no export options.
17. PCalc Lite (universal)
PCalc Lite's existence means the lack of a built-in iPad calculator doesn't bother us (in fact, we'd love to replace the iPhone Calculator app with PCalc Lite as well). This app is usable and feature-rich - and if you end up wanting more, in-app purchases enable you to bolt on extras from the full PCalc.
18. Reuters News Pro for iPad
Reuters offers the next best free news app for iPad with its Reuters News Pro for iPad. It's worth downloading for a more international take on news coverage than your usual news apps provide.
19. Cooliris (universal)
Long ago, Cooliris lived within browsers, converting online galleries into 3D walls of thumbnails you could zoom along. On the iPad, the concept seems more at home. It's of course a gimmick, but it's a great-looking and tactile one, and more fun than using the Photos app to rummage through your snaps.
20. Wikipanion for iPad
The Wikipedia website works fine in Safari for iPad, but dedicated apps make navigating the site simpler and faster. We went back and forth between Simplepedia and Wikipanion, eventually plumping for the latter, largely due to its efficient two-pane landscape view with excellent bookmarking and history access.
21. eBay for iPad
Use eBay for iPad and you'll never touch eBay in a web browser again. It's fast and efficient, beautifully showcasing important details and images in its main results view. Gallery images can often be displayed almost at a full-screen size, which is particularly useful on an iPad with a Retina display. Speedy sorting options are also available.
22. Soundrop (universal)
Soundrop is a minimal generative sound toy that offers an endless stream of balls, which make noises when they collide with and bounce off user-drawn lines. The overall result is surprisingly fun and hypnotic. For more advanced features - save, multiple instruments and gravity adjustment - there's an in-app "pro" purchase option.
Wallpaper apps litter the App Store, but are mostly dull, offering photos of brick walls or bored animals. Granimator is a bonkers art tool, enabling you to choose a background and spray all manner of shapes around. Compositions can be fine-tuned by dragging objects, and then shared to Flickr, Twitter or your device's Photos app.
24. Google Earth (universal)
It's not the smoothest app in the world, and it lacks some elements from the desktop, but Google Earth is nonetheless a joy on the iPad. Touch gestures are an intuitive means of swooping around the planet, and the optional layers enable you to display as much or as little ancillary information as you wish.
25. Explore Flickr (universal)
Explore Flickr provides an engaging way to discover new photography. On launch, your iPad screen fills with a grid of thumbnails, drawn from Flickr.com's top daily images. Tap one to view (and, if rights permit, download to your device), or just leave the app lazily updating (every now and again, a thumbnail spins to reveal a new image) while your iPad charges in its dock.
26. Rj Voyager
One for budding iPad DJs, Rj Voyager enables you to choose from a selection of bundled tracks, turn parts on and off and edit parameters in real-time via an intuitive, futuristic interface. Play through headphones or a decent sound system and the result is infectious.
27. Waze (universal)
Move aside Google Maps, Waze
28. Epicurious (universal)
Tens of thousands of recipes at your fingertips (as long as you have a web connection) ensure Epicurious is worth a download for the culinary-inclined. The app even composes a handy shopping list for recipes.
29. WordPress (universal)
This official WordPress app has a reputation for being a bit clunky, but it's fine for authoring the odd blog post on the go, along with making quick edits to existing content and managing comments. It also offers both text-based and visual approaches to crafting posts, so you're not stuck with HTML.
30. Speedtest X HD (universal)
Truth be told, we're always a touch suspicious of apps that claim to test your connection speed, but Speedtest X HD seems to do a decent job. It's also handy to have installed for when your broadband goes all flaky and you need to record the figures for a subsequent moan at your ISP.
31. Adobe Photoshop Express (universal)
With people regularly moaning about bloat in Adobe's desktop applications, it's great to see the giant create something as focused and usable as Adobe Photoshop Express. Its toolset is strictly for basic edits (crop, straighten, rotate, flip, levels and lighting adjustments), and applying a few effects, but the app is fast, stable and extremely useable. Top notch.
32. Mint (universal)
Mint is a safe and secure way to make the budgeting process much easier by tracking your spending and providing nice little charts and graphs. Open an account, add your bank, credit, loan and retirement accounts and Mint will automatically pull in and categorize your transactions.
33. Find my iPhone (universal)
Find my iPhone would perhaps be better named "Find my Apple stuff," because it's not just for figuring out where a missing iPhone is - it can also track iPads, iPods and Macs. The app is simple, elegant and, generally speaking, provides an accurate location for devices. It also enables you to remote-lock or wipe a device.
34. Flipboard (universal)
Initially, Flipboard looked like a gimmick, trying desperately to make online content resemble a magazine. But now it can integrate Flickr and other networks, beautifully laying out their articles, Flipboard's muscled into the "essential" category - and it's still free.
35. Find My Friends (universal)
While perhaps less practical than on the iPhone, Find My Friends on the iPad nonetheless works well, enabling you to track any pals that are happy with you digitally stalking them. The iPad's large display improves the app's usability, simultaneously displaying your friend list and a map.
36. IMDB (universal)
IMDB is a great way to browse more movie-related info than you could ever hope to consume in a single lifetime. Settings enable you to define which sites IMDB and Amazon info is taken from, and the show times finder works pretty well.
37. Pocket (universal)
Pocket and Instapaper have long battled it out for "article scraper" king, but Pocket trumps its rival in appealing to iPad-owning cheapskates. Instapaper requires a purchase for iPad goodness, but Pocket is free. It's also very fast, offers tagging, includes a great original article/plain-text toggle, and has a vaguely Flipboard-like visual grid-based index. It's also been updated recently to provide an even better experience.
38. TED (universal)
TED describes itself as "riveting talks by remarkable people, free to the world." The app pretty much does as you'd expect - you get quick access to dozens of inspiring videos. However, it goes the extra mile in enabling you to save any talk for offline viewing, and also for providing hints on what to watch next if you've enjoyed a particular talk.
39. Twitter (universal)
This app used to showcase some breathtaking iPad UI innovation, but in its quest for cross-platform consistency, Twitter has refashioned its tablet offering as a blown-up version of the iPhone app. The result is a far less exciting experience, but one that's nonetheless very usable, and which unlike third-party apps rolls in the service's Interactions and Discover tabs.
40. Virtuoso Piano Free 2 HD
There's not a great deal to piano app Virtuoso Piano Free 2 HD, but it's not bad for a freebie. You get a dual-keyboard set-up, with optional key labels, and you can shift octaves and notes by prodding arrows. A really nice touch is the "duette" [sic] button, which creates a second, mirror image, keyboard, so that two people can play at once.