GOMAD Calculator
GOMAD — a gallon of milk a day — adds roughly 2,400 kcal on top of your regular diet, making it one of the simplest ways to create a large calorie surplus. Enter your current intake and milk ratio in the calculator above to see projected daily calories and an estimated weekly weight-gain range. This page also covers the real downsides you should weigh before starting.
🧮 GOMAD Calculator
What GOMAD Actually Means
GOMAD stands for "Gallon Of Milk A Day." The idea is straightforward: drink one US gallon (3.78 litres) of whole milk every day on top of your normal meals. Whole milk contains roughly 150 kcal per cup, so a full gallon — 16 cups — delivers approximately 2,400 kcal, 128 g of protein, 192 g of carbohydrates (mostly lactose) and 128 g of fat.
The approach became popular in strength-training circles because it removes the need to plan or cook extra meals. You simply drink milk throughout the day alongside your regular food. For someone whose maintenance is 2,500 kcal, adding a full gallon pushes total intake to around 4,900 kcal — a surplus large enough to gain roughly 1–2 kg per week.
Most people do not need the full gallon. The calculator on this page lets you set a percentage — 25, 50, 75 or 100 percent — so you can scale the approach to a surplus that suits your calorie target without the extreme volume.
Honest Downsides of GOMAD
GOMAD works for weight gain, but a significant portion of that weight will be fat. A 2,400 kcal daily surplus far exceeds what the body can channel into muscle, even with intense resistance training. Surpluses above +500 kcal per day increasingly favour fat storage over lean tissue.
Digestive discomfort is the most common complaint. Drinking nearly four litres of milk stresses the gut, and many adults have some degree of lactose malabsorption — symptoms include bloating, gas, cramping and diarrhoea. Acne flare-ups are also frequently reported, likely linked to the hormonal content of dairy and the sheer volume consumed.
There is also a cardiovascular consideration: a gallon of whole milk contains roughly 128 g of fat, of which about 80 g is saturated — far above most daily saturated-fat guidelines. Short-term protocols of two to four weeks limit exposure, but longer runs amplify these risks. If you have a history of digestive issues, lactose intolerance or high cholesterol, talk to your doctor before attempting GOMAD in any amount.
How to Use the GOMAD Calculator
Select what fraction of a gallon you plan to drink each day — the tool offers 25, 50, 75 and 100 percent presets. Enter your current daily calorie intake (or use a calorie surplus calculator to estimate maintenance first), and the tool projects your total daily intake, surplus size and estimated weekly weight-gain range.
The weight-gain estimate uses the rough guideline that approximately 7,700 kcal of surplus translates to about 1 kg of body weight. This is a simplification — actual results depend on metabolism, training intensity, sleep and genetics — but it gives a useful planning figure.
If the projected surplus looks too aggressive, drop the milk percentage. A half-gallon (50 percent) still adds around 1,200 kcal per day, which combined with solid meals can produce steady, more manageable gains. The goal is a surplus you can sustain for several weeks without gut distress or excessive fat accumulation.
Partial GOMAD and Alternatives
If you want the convenience of liquid calories but not the extremes of full GOMAD, consider partial approaches. A quarter gallon (roughly 950 ml) adds about 600 kcal — enough to meaningfully boost your surplus when combined with calorie-dense meals. You can also replace some of the milk with a homemade shake that uses oats, peanut butter and protein powder for a more balanced macro profile.
Some trainees cycle GOMAD: two weeks on a half-gallon, one week off, then reassess body composition. This limits fat gain and gives the digestive system a break. Others use GOMAD only on training days and eat at a smaller surplus on rest days.
Whatever approach you choose, weigh yourself at the same time each morning and track a seven-day average. If the scale moves faster than about 0.5 kg per week beyond the first water-weight adjustment, your surplus is likely too large and more of the gain will be fat than muscle.
Frequently asked questions
How much weight will I gain on GOMAD?
On a full gallon per day, most people gain 1–2 kg per week. However, a large portion of that is fat and water retention, not lean muscle. Reducing to a half or quarter gallon produces slower but leaner results.
Can I do GOMAD with lower-fat milk?
You can, but the calorie count drops substantially. Lower-fat milk provides fewer calories per serving, so you would need to increase volume or add other calorie sources to match the same surplus. Enter your chosen milk type into the calculator to see the adjusted projection.
How long should I stay on GOMAD?
Most people run GOMAD for two to four weeks. Longer periods increase fat gain and digestive strain. After a short run, switch to a more moderate surplus and assess whether the weight you gained aligns with your goals.
Is GOMAD safe for lactose-intolerant people?
Generally, no. Even partial GOMAD delivers a large amount of lactose. If you have confirmed lactose intolerance, the bloating and digestive issues will likely outweigh the calorie benefits. Consider lactose-free milk or non-dairy alternatives instead.