Dog Calorie Calculator for Weight Loss
A dog losing weight is fed against its target weight, not the weight on the scale. Resting energy is RER = 70 × (target weight in kg)0.75, and the daily target is 70–90% of that RER. For a 30 kg dog with a 25 kg target: 70 × 250.75 = 783 kcal at rest, so 548–704 kcal a day across the published range, and 626 kcal a day at 0.80 — the setting the published selector marks as its common starting point. Below: every constant, the safe rate of loss in grams a day, and the whole chain in numbers you can redo on a phone calculator.
Enter a current weight, a target weight and a feeding factor
A measured weight, not a guess. The unit applies to both weight boxes. The defaults show the worked example: 30 kg now, 25 kg target.
The weight your veterinary team gives you for the dog at a healthy body condition. This page does not score body condition for you — it takes the target as given.
These five are the settings the published weight-loss selector offers. Start high and step down rather than the other way round.
From the bag or can, in kcal per cup. Leave it if you do not know it yet — everything above still works.
What the dog is actually eating today, including treats. Used only to show the size of the cut.
Everything is calculated in your browser. The numbers you type are not sent anywhere.
Daily target and rate of loss
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kcal per day
Calories are rounded to the nearest whole kcal; grams and cups to one or two decimals. The same rounding rule is used in the tables below.
Enter a current weight and a target weight to see the working.
Which weight the calculator is actually using
This is the single thing that separates a weight-loss calculation from a maintenance one, and it is the thing most people get wrong when they reach for a normal dog calorie calculator. A maintenance calculator uses the dog in front of you. A weight-loss calculation uses the dog you are aiming at.
Line 1 RER = 70 × (target weight in kg)0.75 Line 2 target = RER × feeding factor (factor 0.70 to 0.90) Line 3 excess = current weight − target weight
Written as one line, so you can type it straight into a phone calculator:
daily kcal = 70 × (target kg0.75) × factor
The three veterinary planners ranking above this page for this keyword do not agree on this. Read on 10 October 2026, two of them build the daily target from the dog's lower body weight — the weight it is heading for — and the third builds it from the weight at the start of the planning step, which on the first step is the weight on the scale today. Same equation, two different inputs, and the gap is not small: for the worked example below, the target at 0.80 comes out at 626 kcal a day on the target weight and 718 kcal a day on the current weight — 92 kcal a day apart, 15% higher. Neither figure is wrong on its own arithmetic, but they are not comparable, and neither of the pages prints the difference.
The same equation, the same 0.80 setting, two different base weights:
| Base | Weight used | RER | Target at 0.80 |
|---|---|---|---|
| Target weight this page | 25 kg | 783 | 626 |
| Current weight | 30 kg | 897 | 718 |
| Difference | 5 kg | 114 | 92 kcal = 15% higher |
What each symbol means
- RER — resting energy requirement, in kcal a day. Energy spent at rest. Not a feeding target on its own.
- target weight — the weight at a healthy body condition, in kilograms. Convert first, then raise to the power.
- feeding factor — how much of RER the dog is fed. For weight loss the published range is 0.70 to 0.90.
- excess — how much has to come off, in kilograms. Used only to work out how long, never to set the calories.
The weight-loss factor, printed as calories instead of labels
The published selector offers five settings between 0.70 and 0.90 of RER, and marks 0.80 as its common starting choice. Labels do not tell you what you will be feeding. Here is the same five, run through the equation at the 25 kg target weight from the worked example, so each row is a number you can put in a bowl.
At a 25 kg target weight (RER = 783 kcal a day):
| Factor | Setting | kcal a day at 25 kg |
|---|---|---|
| ×0.70 | most restrictive | 548 |
| ×0.75 | restrictive | 587 |
| ×0.80 | the common starting point this page's default | 626 |
| ×0.85 | cautious | 665 |
| ×0.90 | least restrictive | 704 |
The whole band is 156 kcal wide. That is a real difference at feeding time: the most restrictive setting is 22% below the least restrictive one. Which end you start at is a veterinary decision, not an arithmetic one — but whichever end is chosen, the number you feed is the number in that row, not a guess.
The safe rate of loss, in grams a day
The published guidance for dogs is a loss of 1–2% of body weight per week, with treats kept to no more than 10% of the daily total. A percentage of body weight is hard to act on. Grams a week is what a kitchen scale shows.
For the worked example — 30 kg now, 25 kg target, 5 kg to lose:
| Rate | kg a week | g a week | g a day | Weeks to close 5 kg |
|---|---|---|---|---|
| 1% of current weight | 0.30 | 300 | 42.9 | 16.7 |
| 2% of current weight | 0.60 | 600 | 85.7 | 8.3 |
| 1% of target weight | 0.25 | 250 | 35.7 | 20.0 |
| 2% of target weight | 0.50 | 500 | 71.4 | 10.0 |
Two things to read off this table. First, the same 2% applied to the target weight instead of the current weight stretches the schedule from 8.3 weeks to 10.0 weeks. Second, the week counts assume the percentage keeps applying to the same starting weight. The published planner notes that its own projection compounds, so the amount coming off each week shrinks as the dog gets lighter. That makes these figures the fastest case, not a promise.
From the daily target to food in a cup
The target is in kcal; food is measured in cups. One division bridges them, and the only input is the number printed on the bag. It matters more than people expect, because two adult maintenance foods can differ by 40% in energy per cup.
626 kcal a day, split over 2 meals:
| Food energy | Cups a day | Cups a meal |
|---|---|---|
| 300 kcal/cup | 2.09 | 1.04 |
| 330 kcal/cup | 1.90 | 0.95 |
| 360 kcal/cup | 1.74 | 0.87 |
| 390 kcal/cup | 1.61 | 0.80 |
| 420 kcal/cup | 1.49 | 0.75 |
At the worked example's 360 kcal a cup that is 1.74 cups a day, or 0.87 cups a meal. Change the food without changing the target and the cup count moves even though the calories did not — which is the whole reason the target is set in kcal and the scoop is the last step, not the first.
The same equation at other target weights
The 0.75 exponent is what makes the target move in a curve rather than a straight line: a dog twice as heavy does not need twice the calories. This table is the equation at the 0.80 setting across a range of target weights, so you can read your own off the page.
| Target weight | Pounds | RER (kcal a day) | Target at 0.80 |
|---|---|---|---|
| 5 kg | 11 lb | 234 | 187 |
| 10 kg | 22 lb | 394 | 315 |
| 15 kg | 33.1 lb | 534 | 427 |
| 20 kg | 44.1 lb | 662 | 530 |
| 25 kg | 55.1 lb | 783 | 626 |
| 30 kg | 66.1 lb | 897 | 718 |
| 40 kg | 88.2 lb | 1,113 | 891 |
The highlighted row is the worked example. Between 5 kg and 40 kg the target goes from 187 to 891 kcal a day — about 376% more calories for 8.0× the body weight. That gap is the exponent doing its job.
The worked example, line by line
Every figure below comes from the two lines at the top of this page plus the inputs in the calculator. Nothing else is used, so you can reproduce all of it.
Dog: 30 kg now, 25 kg target (66.1 lb now, 55.1 lb target)
Excess: 30 − 25 = 5 kg
Target weight raised: 250.75 = 11.1803
RER: 70 × 11.1803 = 783 kcal a day
Factor: 0.80 × RER
Target: 783 × 0.80 = 626 kcal a day
Full band: 0.70 → 548 0.75 → 587 0.80 → 626 0.85 → 665 0.90 → 704
If the base were the CURRENT weight instead (what the step-start reading does):
70 × 300.75 = 897 kcal, × 0.80 = 718 kcal a day
difference: 718 − 626 = 92 kcal a day (15% higher)
Safe loss: 1–2% of 30 kg = 300–600 g a week = 42.9–85.7 g a day
Weeks: 5 kg ÷ 0.60 kg a week = 8.3 weeks at 2%
5 kg ÷ 0.30 kg a week = 16.7 weeks at 1%
Food: 626 ÷ 360 kcal a cup = 1.74 cups a day
1.74 ÷ 2 meals = 0.87 cups a meal
Treats: 10% of 626 = 63 kcal a day (inside the target, not on top of it)
Cut: 900 eaten now − 626 target = 274 kcal a day
One line deliberately stops there: the 274 kcal a day is not converted into grams of body weight lost per day. That conversion needs an energy value for body tissue, and no source read for this page gives one, so this page does not print one. The grams in the table above come from the published rate of loss, which is measured in body weight rather than in calories.
Where every number on this page comes from
Nothing here is a house estimate. Each constant is either a published figure or arithmetic on your own inputs, and the table says which.
| Constant | Value used here | Where it comes from |
|---|---|---|
| Resting-energy equation | RER = 70 × kg0.75 | The standard veterinary resting-energy equation. Read live on 10 October 2026: one of the three veterinary planners ranking above this page prints it in this same form, on the weight at the start of each planning step; the other two use RER without printing it. It is not their formula and this page does not attribute it to them. |
| Which weight the target uses | the target weight here — the three pages above do not agree | Read live on 10 October 2026 from the three veterinary weight-management planners ranking above this page: two build the daily target from the dog's lower (target) body weight, and one builds it from the step-start weight. This page uses the target weight, and the table above prints what the other choice costs. |
| Feeding factor for weight loss | 0.70 / 0.75 / 0.80 / 0.85 / 0.90 × RER | Same read, 10 October 2026: the published selector offers exactly these five settings and marks 0.80 as the common starting choice. |
| Safe rate of loss, dogs | 1–2% of body weight a week | Same read, 10 October 2026: printed on the report of the calculator ranking first for this keyword. (Its figure for cats is lower; this page is about dogs.) |
| Treat allowance | up to 10% of the daily target | Same read, 10 October 2026: stated in the same sentence as the rate of loss. |
| Unit conversion | 1 lb = 0.45359237 kg | Definition of the international avoirdupois pound. |
| Food energy per cup | 360 kcal in the example | A food label. The page does not assume a value; it takes yours. |
| Current and target weight | 30 kg and 25 kg in the example | A measured weight, and the target weight from your veterinary team. |
The two competitor readings above were taken on 10 October 2026 in a browser session, from the pages ranking above this one for this keyword, and what was read is recorded in this site's own publishing ledger. The equation itself is not attributed to them: it is the standard resting-energy equation, and they do not print it.
What this page covers, and what it deliberately does not do
Covers
- The equation, with the constant and the exponent written out.
- Which weight goes into it for a weight-loss plan, and the fact that the three pages ranking above this one do not agree on it — with both answers computed so the difference is visible.
- All five published feeding factors, each converted to kcal a day at a worked target weight.
- The published safe rate of loss, converted from a percentage into grams a week and grams a day.
- The same arithmetic at a range of target weights, and the unit conversion in both directions.
- Where each constant comes from, named in the source table above.
Deliberately not done here
- No calorie-to-grams-of-body-weight conversion. Turning a daily kcal deficit into grams of fat lost needs an energy value for body tissue, and no source read for this page provides one. The grams on this page come from the published rate of loss, which is a body-weight figure.
- No body condition scoring. The page takes the target weight as given. Scoring the dog is a hands-on assessment, not a calculator.
- No plan for puppies, pregnant or nursing dogs, or dogs with a medical condition. The 0.70–0.90 band is a weight-loss band for adult dogs. Other life stages have their own factors and their own supervision.
- No finish date. The published projection compounds, so the honest output is a range of weeks, not a date to circle.
- No invented factors. The five settings are the published five. There is no sixth.
- No stored inputs. The arithmetic runs in the browser and there is no report to print.
Questions
How many calories should a dog eat to lose weight?
Work out the resting energy from the target weight — 70 × (target kg)0.75 — then feed 70–90% of it. For the worked example, a 25 kg target gives 783 kcal at rest, so 548–704 kcal a day, and 626 kcal a day at the common 0.80 setting.
Does a dog calorie calculator for weight loss use the current weight or the target weight?
This page uses the target weight, and that is the one point on which the pages ranking above it disagree. Read on 10 October 2026, two of them use the dog's lower (target) body weight and one uses the weight at the start of the planning step. For the worked example the two answers are 626 and 718 kcal a day — 92 kcal apart. The current weight is used on this page only to work out how much has to come off and how long that takes.
What percentage of body weight should a dog lose per week?
The published figure for dogs is 1–2% a week. For a 30 kg dog that is 300–600 grams a week, or 42.9–85.7 grams a day.
Where does the target weight come from?
From your veterinary team, who can assess the dog by hand. This page does not estimate it from a photo, a breed or a body condition score, because a target weight chosen that way would be a guess dressed up as a number.
Is 0.80 of RER the right setting to start at?
It is the one the published selector marks as its common starting choice, and it sits in the middle of the 0.70–0.90 band. Which setting a particular dog should be on is a veterinary decision. The point of printing all five as calories is that you can see exactly what each step down costs before it is taken.
How many cups of food is that?
Divide the daily target by the calories per cup on the bag. At 360 kcal a cup and a 626 kcal target, that is 1.74 cups a day — 0.87 cups a meal over 2 meals. Change the food and the cup count changes even if the target does not.
How long will it take?
At the published rate of loss, 5 kg comes off in roughly 8.3 weeks at 2% a week or 16.7 weeks at 1%, assuming the rate keeps applying to the starting weight. The published planner notes its own projection compounds, so treat those as the fastest case.
Why does this page give a range instead of one number?
Because the published feeding factor is a range, and so is the published rate of loss. A single number would be this page's invention, not a published figure. The calculator does pick one number for you — the one at the factor you selected — and shows the rest of the band next to it.
Can I use this for a puppy, a pregnant dog, or a dog on medication?
No. Those need their own factors and their own supervision. This page is for adult dogs on a weight-loss plan, and the numbers change completely outside that case.
Is it free, and do I need an account?
Free, no account, no sign-up. The arithmetic runs in your browser.
Is this veterinary advice?
No. It is arithmetic on published figures. It does not diagnose anything and it cannot examine the dog. If the dog is unwell, is not eating, or the weight is not moving as expected, ask your veterinary team rather than changing the number.