An archery toolbox for calculating proper arrow spine.

In-App purchases unlock Premium Features.

The app uses a configuration created from the user's bow definition and desired arrow parameters.

It is the only handheld app available for shaft selection that is based on bow performance. It has the same features and flexibility as the desktop app available from Pinwheel Software.

You can search by shaft manufacturer, shaft construction (aluminum, carbon, aluminum/carbon), and shaft usage (target, hunting, both).

You can search the database for a specific weight range for a completed arrow (with your components), a shaft diameter range, or a specific percent FOC range. Choose to include or omit discontinued shafts.

Flexible, Accurate, Unique.

What’s New

Version 1.6

Enhanced support for database updating.
Replaced Quick Change sliders with Up Down Buttons.
Minor bug fixes.

Ratings and Reviews

1.5 out of 5
11 Ratings

11 Ratings

Tus Hlub ,


Controls are clunky when sliding the pointer to desired value. Your arrow selections are also limited. When you configure your arrow and set up, you have a list of 5 arrows of which I’ve never even heard of to experiment with. Where are the Easton/gold tip/carbon express arrows? I would’ve thought you would at least get those as an option. You also pay for the app, but still have to pay more for the “premium functions”.

Developer Response ,

Sliders were replaced by up/down buttons in the current app version.

The "Placeholder" shaft database is the default database the app uses to show basic functionality.

A complete arrow database..2019 Database available as a Premium Feature In-App purchase for $1 ($0.99). There are approximately 42 current and discontinued manufacturers in the Premium Feature 2019 Database.

The app will accurately calculate SPINE,FOC,MO,KE,TAW,and FPS..even if you choose not to upgrade to the premium database.

Traviswdalton ,

Needs improvement

I have the windows version of this and love it. I contacted the developer about some improvements. Hopefully I’ll get a response and I’ll update review accordingly.

Update: developer emailed me within the hour. Everything I wanted was already there I simply had to flick the screen up.

jon.dingo ,

Bad results

I was skeptical of the app because it did not match the arrow manufacturers recommended spine. Sure enough the two shafts I purchased based on the app results where under spined and not tunable. Not only did I waste $5 making this app usable I wasted $24 on under spined arrows. Save your money and just use the arrow manufacturers recommended spine chart.

Developer Response ,

If you provide accurate user input, the app will accurately calculate SPINE,FOC,MO,KE,TAW,and FPS.


Pinwheel Software, Inc.
54 MB

Requires iOS 7.0 or later. Compatible with iPhone, iPad, and iPod touch.

Age Rating
Rated 4+
© 2017 Pinwheel Software, Inc.
In-App Purchases
  1. 2019 Database Access $0.99
  2. Quick Change Feature $0.99
  3. Save 5 User Records $1.99


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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