Gammon API Gravity Calculator 4+

Gammon Technical Products

Designed for iPhone

    • 4.0 • 8 Ratings
    • $9.99

iPhone Screenshots


The GTP API Gravity Calculator from Gammon Technical Products, Inc. provides users the ability to determine corrected API at 60 Deg F for jet, gasoline, and diesel fuels. The calculator is a digital version of our GTP-3012-1A and GTP-2727EF slide calculators and it also is capable of calculating the total weight of the fuel.

What’s New

Version 1.0

This app has been updated by Apple to display the Apple Watch app icon.

Ratings and Reviews

4.0 out of 5
8 Ratings

8 Ratings

Ace00731 ,

Works great but could use a better UI

This works great and I double checked with the wheel, though this could use a better user interface look. There is much unused white space in the app where they could have made the text and input boxes larger to scale with screen, because the numbers are small.

18ldm ,

I use this daily

I use this app on a daily basis. I used to haul Jet A, so we’re always having to sample before offloading. Yeah there was a time or two where I was .01 or .02 off from the receivers wheel, but not far enough off for them to reject the load. I now haul gasoline, and utilize this app for loading my truck based off of the gravity/weight of the fuel. I will find out what the gravity is, enter it in and the see how many gallons I can load based off of the weight. I’ve been able to load anywhere from 50 gallons to 500 gallons more then I used to haul. Bigger payload equals more money. I was really hesitant at first loading my truck this way, so I slowly started adding 50-100 gallons to verify the weight calculations. I’ve been doing it this way now for a few months and haven’t had any problems with going through weight stations. I’m always within a couple hundred pounds of what I can legally gross.

As far as other things the previous reviews said, I agree with the waste of space on the screen and small numbers.

As far as selecting the type of fuel, I had that problem at first also. But it’s actually irrelevant anyway, it doesn’t matter if you’re dealing with jet, diesel or gasoline, the numbers always come out the same as long as you enter them correctly.



I purchased this for easier reading of API Gravity readings when receiving fuel loads. I’ve checked it a few times against the “wheel” and it’s been .02 to .04 higher with each reading. That can result in a rejected load of fuel. Spent $10 on a item I can’t rely on.

App Privacy

The developer, Gammon Technical Products, has not provided details about its privacy practices and handling of data to Apple.

No Details Provided

The developer will be required to provide privacy details when they submit their next app update.


  • Family Sharing

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

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