iPhone Screenshots


True Proof calculates the true proof of a water-alcohol mixture at a reference temperature, using the measured apparent proof from a hydrometer reading and the temperature at the time of the reading.

True Proof also performs gauging calculations, and can calculate dilutions taking full account of the temperature-dependent nonideal mixing of water and alcohol.

Calculations are logged, and may be annotated and emailed for archiving.

Multiple units support large-scale distillers and hobby-scale distillers alike, in the US and abroad: concentration measurement in proof, ABV, or density ; temperature in °F or °C; abundance in US gallon, liter, pound, kg, US ton, or metric tonne, etc.

The reference temperature can be selected for US (60ºF) or international (20ºC), or any other value in the range [-20ºC,40ºC]. The instrument thermal expansivity can be selected, which enables application to vibrating tube densitometers in addition to hydrometers.

Two separate computational models are employed - one based on the (US) TTB gauging manual, and one based on OIML (UK, EU, Canada, etc) data. The computer model is limited in temperature and proof range to that spanned by government standard tables.

What’s New

Version 2.40

Quelque chose pour nos amis Seychellois - enable use of comma as decimal separator. Also bug fix, improved keyboard dismissal, change color scheme for dark mode compatibility.

Ratings and Reviews

5.0 out of 5
3 Ratings

3 Ratings

Ditsrillery User ,

Perfect Handheld App!

As a professional distiller, I have to constantly stop and calculate the proof of the product multiple times during the day. This app is great; it’s quick and easy to calculate proof on the fly while working and not have to interrupt your work constantly to figure it out longhand or leave the production area to do it on a computer. Love it.

E.J. Crowley ,


This app is the best $0.99 purchase of my life. Having bought this, I have since found fulfillment in my life and attained nirvana. Purchase to experience spiritual rebirth.

Ryan.MC. ,

TRUE Genius

Great app. It's going to make figuring out how potent my moonshine is much easier. Thank you Greg Miller.

Update 3/13/15: The new update is great. The attention to detail is just what I need.

App Privacy

The developer, Greg Miller, has not provided details about its privacy practices and handling of data to Apple. For more information, see the developer's privacy policy.

No Details Provided

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


Greg Miller
8.3 MB

Requires iOS 12.0 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating
Frequent/Intense Alcohol, Tobacco, or Drug Use or References


  • Family Sharing

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

You May Also Like