Need to know how much your steer or pig weighs, but there is no scale nearby? The question comes up when you sort a group, plan feed or talk to a buyer, and many people have heard of apps that weigh an animal with a phone.
The truth comes before the app: no phone weighs an animal. What these apps do is estimate the weight from measurements taken with a tape, using formulas that are well known in livestock farming. It is a calculation, not a weighing.
Here we show two apps that run this calculation, how to take the measurements the right way, how far off the result can be and when the scale is still the only safe answer.
Start with Animal Weight 👇
6 min read
📋 What you’ll find here
- Can a phone weigh cattle?
- How the estimate works
- How to take the measurements the right way
- Animal Weight: the HorDev calculator
- Cow Weight Calculator: an Android-only option
- What about apps that weigh from a photo?
Key Takeaways
- No app weighs the animal: they estimate the weight from the measurements you take
- Animal Weight, from HorDev, is on Android and iPhone; Cow Weight Calculator is Android only
- The developer of Animal Weight mentions an error of 3% to 10%: on a 400 kg (about 880 lb) steer, that can mean up to 40 kg
- The most important measurement is the heart girth, with the tape snug just behind the shoulders
- To sell by weight, dose medicine or decide on slaughter, use a scale
Can a phone weigh cattle?
No. A phone has no sensor that can measure mass, and the camera only sees size and shape. Any number on the screen is the result of a calculation made with measurements, either the ones you type in or the ones the app tries to take from a photo.
That does not make the apps useless. A good estimate helps you follow how a group gains weight and plan feed. It just cannot be treated as if it came from a scale.
How the estimate works
The weight of cattle or pigs follows the heart girth and the body length closely. The formulas used in livestock farming combine these two measurements and return an approximate weight. It is the same idea as the weight tape sold at farm supply stores, which already has the estimated weight printed on it.
The app does the math for you and keeps the result. The quality of the number depends almost entirely on the measurement: a loose tape or one in the wrong place changes the result by several kilos.
How to take the measurements the right way
Measure with the animal calm and well positioned. A few simple steps make more difference than the app you choose:
- Animal standing still on level ground, all four feet down and the head in a normal position
- Heart girth: tape snug, just behind the shoulders, going all the way around
- Length: measure between the points the app shows, because each formula uses its own
- Repeat the measurement two or three times and use the average
- Always measure at the same time of day, ideally before the animal eats and drinks
Animal Weight: the HorDev calculator
It is the more installed of the two: Google Play shows more than 500 thousand downloads and a 4.1 rating from 488 reviews. The name changes a little from store to store; on the App Store it appears as Peso Animal, published by Carlos Arevalo, with the same package as the HorDev app on Android.
You type in a few measurements and the app calculates the weight. The App Store description mentions pigs, cattle, buffalo, horses, sheep, goats and dogs, for live or slaughtered animals. The same text warns that the calculation may be off by 3% to 10%.
On Google Play, the app has ads and in-app purchases. On iPhone, it had no ratings at all on November 3, 2026, so there is no way to know how users rate it there.
Cow Weight Calculator: an Android-only option
Cow Weight Calculator, from BepariTeam, is a weight calculator for cattle that exists only on Google Play. The listing shows more than 10 thousand downloads, ads and no in-app purchases. We could not read its rating on the store.
Use it as a second opinion: take the same measurements, run the math in both apps and compare. If the numbers are far apart, measure again before you blame the app.
What about apps that weigh from a photo?
Some apps promise to estimate weight when you point the camera at the animal. The ones we found are new, have few reviews, and the worst reviews talk about results far from reality, especially with calves.
That makes sense: a photo changes with distance, angle, light and the animal’s position, and the app cannot know how much of the volume is muscle, fat or feed in the rumen. That is why we left these apps off the list. Use the tape.
What the estimate is for, and what it is not for
The error grows with animals outside the standard, such as calves, pregnant cows and very thin or very fat animals. The table shows when the estimate helps and when it is better to weigh.
| Situation | What to use |
|---|---|
| Following a group’s weight gain | Estimate, with the same person always measuring |
| Planning feed | Estimate, as a reference |
| Dewormer or medicine dose | Scale, or your veterinarian’s guidance |
| Selling by weight | Scale |
| Deciding on slaughter | Scale |
When the scale is still a must
In any deal paid by the kilo or the pound, the weight that counts is the scale’s. A 10% difference across a whole group turns into a lot of money, one way or the other.
With medicine, the risk is different: a dose calculated on the wrong weight may end up below what is needed or above what is safe. Follow the label and your veterinarian. If you have no scale, look for one at a local co-op, a livestock auction or a neighbor’s farm.
Is it worth it?
It is worth it as a tracking tool, as long as you accept that the number is an estimate. Start with Animal Weight, which is on both stores, and use Cow Weight Calculator on Android to compare.
This article is informative and independent. Ratings, reviews and downloads were checked on Google Play and the App Store on November 3, 2026. We have no connection with the developers mentioned, and we are not responsible for how the apps work, for the accuracy of the estimates or for any sale, treatment or slaughter decision based on them. The store listing is always the final source.
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FAQ
Is there an app that weighs cattle with the camera?
Some apps promise to estimate weight from a photo, but none actually weighs. The ones we saw are new and their reviews mention large errors. The tape estimate tends to be more reliable.
Are the apps free?
Both are free to download. Animal Weight has ads and in-app purchases on Google Play; Cow Weight Calculator has ads and no in-app purchases.
Does it work for pigs?
Animal Weight lists pigs among the species, along with cattle, buffalo, horses, sheep, goats and dogs. Cow Weight Calculator is made for cattle.
Does it work on iPhone?
Of the two, only Animal Weight has an iPhone version, and on the App Store it still had no ratings on November 3, 2026.
Can I sell an animal by the app’s weight?
It is not recommended. When you sell by weight, the scale’s number is the one that counts. The app gives you an idea before you negotiate, not the final price.
