# e: Spacetime Converter > Relativistic spacetime conversion calculator using geometrized units. (iPhone/iPad app by Elliptics, Ltd..) - Source: https://appshunter.io/ios/app/e-spacetime-converter/id291317973 (this page in markdown: same URL + `.md`) - Developer: [Elliptics, Ltd.](https://appshunter.io/developer/289108972) - Category: Education, Utilities - Price: Free - Rating: 5.00/5 from 1 App Store ratings · 10 written reviews indexed - Age rating: 4+ - Requires: iOS 15.5 · 4 MB - Languages: American English - Released: 2022-08-09 - Data updated: 2026-06-05 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/e-spacetime-converter/id291317973/reviews.md ## What is e? Have you thought about how old you are - in meters? Or how tall you are - in seconds? Or how many miles it is until your next birthday? Let's think out of the box, relativistically. While spacetime intervals are constant, length and time can be converted to each other. This calculator makes use of geometrized units (where the speed of light is unity) and lets you convert conveniently between length and time. Is this a useful conversion tool in your day-to-day life? Probably not. But maybe it will let you think about the world a little differently. And amuse your friends and family at the same time! For a technical reference, refer to "Gravitation", by Misner, Thorne and Wheeler, 1973, W.H. Freeman and Company, pp. 35-36. To make things more accessible to the average user, we have tried to avoid displaying scientific notation in numbers as much as possible and, instead, make use of more common terms, such as "billions of miles" and "milliseconds". Now upgraded with the ability to choose different lengths and times for input (inches, hours, days, etc.)! keywords: science, physics, space, time, relativity, calculator ---------------- Reviews from around the world: from Fox Knight, US Love this app!! from highschool student, US Good job, there's a lot of potential here. . . from Turbo elf, US Science geek must buy from Letter Warrior, US I love this idea, especially seeing how far it is until tomorrow, or a friend's birthday. from Professor and wife, US A great application that can also be used by students ... really is a wonderful game. ## Key features - Convert length to time - Convert time to length - Geometrized units (c=1) - Avoids scientific notation - Supports various input units - Educational and entertaining ## Recent user reviews (10 of 10) All indexed reviews: https://appshunter.io/ios/app/e-spacetime-converter/id291317973/reviews.md ### 5/5 — Cool *2009-06-16, version 0* It's a near little thing but it definitly needs more ### 5/5 — Unique and thought-provoking! *2009-04-09* This is one of the most original concepts in a "scientific" calculator, but it allows you to think outside of the normal universe in which we live. As an astronomer, I have endless fun with my fellow astronomers using this to tell them their height in seconds, etc. This App can help anyone get a better grip on the "whole speed-of-light-thing" and the way that cosmologists have to look at the universe in quite different ways. Even if this doesn't necessarily appeal to you, you can still have a lot of fun with this unique converter. Congratulations to Elliptics, Ltd. on a great concept! ### 4/5 — Intresting but... *2009-01-10, version 0* Needs more options -when you tap the result it should change between common terms/ sientific notation/ simple numbers -slideshow backround of space images (maybe the APOD) -needs to convert weight and momentum -not really worth a dollar w/o the things above this point ### 1/5 — Lame cxt=s *2008-12-13, version 0* Get a life ### 5/5 — interesting lol *2008-10-25, version 0* It does what it says, and is kinds interesting to fool with when your bored. I agree with the other reviews that there should be a way to change between seconds, hours, days, feet, inches, etc. Over all I like it, and it's free now!! Good job, there's a lot of potential here. . . ### 5/5 — Love this app!! *2008-10-25, version 0* This app is great, one thing I think would be nice to add is the distance from a day (I.e. May, 14th 1990) to a day in the future (I.e. September, 24th 2044) That's just what I'd like to see in the next update. Please keep up the good work!! ### 4/5 — Science geek must buy *2008-10-03, version 0* Fun to mess with. Just wish you could choose to enter minutes and hours instead of only seconds; also would like to use inches and miles as well. Add those options and it is a solid 5 star app. As is, it is still a science geek must buy. ### 5/5 — A great application that can also be used by students *2008-09-29, version 0* As a political scientist I found an enjoyable outlet for my classes. It will be exciting for my students to play with conversions. This adds a new dimension for a length to time or time to length. Seconds to millions of miles, or meters to nanoseconds are exciting concepts. It really is a wonderful game. ### 5/5 — This shows truth is truly stranger than fiction *2008-09-28, version 0* Just trying to make sense of these scientifically accurate conversions is fascinating and lots of fun. It's so simple and easy to use, giving you an entirely new way to think about the world around us. These interesting conversions can be used to create intriguing guaranteed conversation starters - like arranging to meet someone to go out, in miles from now. The more you think about it the more amazing it gets... ### 4/5 — Interesting, Good Start ... looking for unit choices *2008-09-25, version 0* I love this idea, especially seeing how far it is until tomorrow, or a friend's birthday. I would love to be able to put in Kilometers or miles in addition to meters and feet. Good start! ## Frequently asked questions about e ### What is Spacetime Converter used for? Spacetime Converter allows you to convert units of length into units of time and vice versa, using principles of relativity. It's designed to help users think about the universe in unconventional ways and is a fun tool for science enthusiasts. ### Is Spacetime Converter free to use? Yes, Spacetime Converter is completely free to download and use. It does not have any in-app purchases or advertisements. ### What devices does Spacetime Converter support? Spacetime Converter is available for iPhone and iPod devices. It is designed for iOS users. ### What is the age rating for Spacetime Converter? Spacetime Converter has an age rating of 4+, making it suitable for a wide range of users. The app's content is generally appropriate for children. ### How often is Spacetime Converter updated? Spacetime Converter was last updated on August 9, 2022, with version 3.0. Future updates will depend on developer plans. ### Does Spacetime Converter have ads? No, Spacetime Converter is ad-free. Users can enjoy the application without any interruptions from advertisements. ### Can Spacetime Converter be used for academic purposes? Yes, Spacetime Converter can be a great tool for students learning about physics and relativity. It provides a unique perspective on scientific concepts and is cited as a reference for technical details. ### What makes Spacetime Converter unique? Its uniqueness lies in its application of geometrized units to convert between length and time, encouraging users to think relativistically. It also aims to make complex scientific concepts more accessible by avoiding scientific notation. ## Version history (last 5 releases) ### 3.0 — 2022-08-09 Compatible with the latest iOS versions. Keyboard is a more convenient number keyboard. Switching between metric and imperial units retains values when possible. Bug fixes. ### 2.02 — 2010-10-07 Compatible with iOS 4.1 and tested on iPhone 4. ### 2.01 — 2009-06-26 (1) Ensured compatibility with iPhone OS 3.0. ### 2.0 — 2009-03-22 No release notes. ### 1.0 — 2008-09-23 No release notes. ## Apps similar to e | App | Rating | Price | Category | | --- | --- | --- | --- | | [Relativistic Space-Time](https://appshunter.io/ios/app/relativistic-space-time/id1463093650) | 3.0 (2) | Free | Education | | [RelativityTheory](https://appshunter.io/ios/app/relativitytheory/id1620999874) | — | $0.99 | Education | | [Waldo: Reading Emerson](https://appshunter.io/ios/app/waldo-reading-emerson/id6504142895) | — | Free | Education | | [David City Public Schools](https://appshunter.io/ios/app/david-city-public-schools/id1625319582) | — | Free | Education | | [MOJI Math - Emoji Fun Game](https://appshunter.io/ios/app/moji-math-emoji-fun-game/id1665503442) | 5.0 (1) | $2.99 | Education | | [Russian Phrase Book Learn](https://appshunter.io/ios/app/russian-phrase-book-learn/id1165304149) | 4.5 (2) | $1.99 | Education | --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-05.*