I rarely write reviews, but feel obliged to write one for this wonderful app that finally solved my calendaring problems that were costing me no end of time and missed appointments. I work mainly on Windows with personal email on Microsoft Exchange accounts and organizational email in Google, and also use two iOS devices. I tried pulling all calendars into my Microsoft account, but synchronization was undependable. I tried an on-line calendar sync service and that immediately altered many appointments in a group calendar — really bad. I spend a lot of time checking one calendar against the other. Finally, this One Calendar app has solved my problems. I consider the price I paid for the Premium version on iOS and another modest fee for the Windows app a small price to pay for all the time it has saved in the few weeks I’ve been using it. Not only that, but the user interface is extremely well thought out, very easy to figure out with good customization options. The month and week views are far better than Outlook or Google IMO. Thank you, thank you, thank you. Keep up the great work!

I've tried many calendar and planner apps in the past and have not been completely satisfied. When I stumbled across this one I was pleasantly surprised. It is a simple calendar, but does all the things I ask of a calendar without complicated, unwanted options getting in my way. What I needed was an app that I could sync with my Google calendar and this one works perfectly, not only syncing but apparently doing so real time. I make changes to this calendar and the changes are there in my Google calendar and the reverse is true. I could also sync to other calendars, Outlook for instance, but am not doing that now because I want to keep it simple.My only compaint, if it really is one, is that there doesn't seem to be a way that I can check to see if I have a regular version or a paid version with more features. For what I need it for I would gladly pay. An answer to this from the developer would be appreciated.All in all I am very happy I found this app.

The interface is smooth and easy to use. It has the views that I like with a choice of three views for week. You can see the full month in two of the week view for easy glances at future dates. I have been using Awesome Cal for several years. I like the one cal interface much better. One key feature is missing from one cal…the note and task feature. This is the reason for 4 stars. The other feature that Awesome cal as is the ability to star an event that color codes the entire day. I use this feature to highlight the days of a recurring event that I can attend. Example, I attend some basketball games during the season. I subscribe to the calendar so it lists all games. Instead of looking at each game to see when I can attend, I star it so I can easily and quickly see which game I plan to attend. This feature is a nice to have. That key feature may be a deal breaker. I don’t want to maintain two separate apps. Why doesn’t the app let you edit a recurring event after it has been created? You have to delete it and create a new one if you want to make changes.

My main interest in this app was the basic calendar view - I'm very visual so I like to have my appointments clearly color-coded. Specifically, a large colored bar across the whole event is ideal, vs. the tiny dot that most apps, including Apple's, favor. This is truly a no-frills app that was easy to sync with my accounts/phone etc, and which would be easier to learn and use for those who are low-tech. You can set reminders and have notes and all that too, but its not grinding your coffee in the morning and posting your life on Instagram. Admittedly, I would welcome a few more options to tweak it's appearance, such as font size, etc. but everyone will have their preferences and nit-picks no matter how how good an app is. This deserves 5 stars for reliably doing exactly what it is designed to do in a logical, very easy-to-use format.