Grains: Archery Calculator 4+

37 South, LLC

Designed for iPhone

    • $1.99

iPhone Screenshots


Grains is a simple archery calculator that makes it convenient to calculate a few important numbers like total weight, FOC (front of center), speed, and energy.

Total Weight: When building an arrow, you're working with many small components with various weights. Grains helps you keep track of each component's weight and see your total arrow weight and how individual components will affect it.

FOC: Your arrow build's front of center percentage is an important factor when it comes to building an accurate hunting arrow. It's a relatively simple calculation to do, but Grains makes it even easier, even offering some advice for an ideal setup and the how-to of getting an accurate measurement.

Speed: Arrow speed is another factor that's important in building the perfect arrow. The slower the arrow, the more likely you are to experience game "jumping the string." Grains uses a standard formula to calculate an estimate of how your bow setup and arrow build might be performing.

Energy: A fast arrow with good FOC is only good if it carries enough energy. Arrow weight and speed can give you the total energy that your arrow will carry, and Grains will also show you what game your arrow build works for.

What’s New

Version 1.1

Bug fixes and improvements.

Ratings and Reviews

5.0 out of 5
5 Ratings

5 Ratings

Edit????? ,

Exactly what I was looking for

I’ve been looking for a simple calculator for my arrows. This does that and more, and it’s so simple to use.

App Privacy

The developer, 37 South, LLC, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Collected

The developer does not collect any data from this app.

Privacy practices may vary, for example, based on the features you use or your age. Learn More


  • Family Sharing

    Up to six family members can use this app with Family Sharing enabled.

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