Calorie surplus calculator.
Find your maintenance calories, the daily surplus, and the exact target intake to build muscle. Pick a surplus size and the tool shows your target calories, the weight-gain rate to expect, and a protein range for muscle gain - in pounds or kilograms.
Calculate your surplus
your numbers
Maintenance (TDEE)
0 kcal/day
Daily surplus
+0 kcal/day
Target daily calories
0 kcal/day
Estimates only, based on the Mifflin-St Jeor equation and the ~7,700 kcal/kg (3,500 kcal/lb) energy rule. Only part of the gain is muscle - the rest is fat, water and glycogen. Track your real weight trend for 2-3 weeks and adjust. Not medical advice.
the short answer
A calorie surplus calculator finds your target intake as maintenance calories (TDEE) plus a daily surplus. TDEE = Mifflin-St Jeor BMR x an activity factor. Add about 150 to 250 kcal for a lean gain, 250 to 500 for a standard bulk, or 500 or more for an aggressive push. So from a 2,700 kcal maintenance, a standard +375 surplus is roughly 3,075 kcal a day - pointing to about 0.25 to 0.5 kg (0.5 to 1 lb) of bodyweight gain per week, only part of which is muscle. Set protein at 1.6 to 2.2 g per kg.
What is a calorie surplus and how big should it be?
A calorie surplus is eating more calories than your body burns in a day, which gives it the spare energy to build muscle and add bodyweight. To turn that into a number you need two things: your maintenance calories and the size of the surplus you want to run.
First, maintenance - your TDEE (Total Daily Energy Expenditure). This calculator uses the Mifflin-St Jeor equation for BMR: BMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age + 5 for men, and - 161 instead of + 5 for women. BMR is then multiplied by an activity factor (1.2 sedentary up to 1.9 athlete) to get TDEE. Imperial inputs are converted to metric internally before the math runs. It is the same maintenance math the calorie deficit calculator uses, only run in the other direction - and if you just want that maintenance number on its own, the maintenance calorie calculator returns it directly.
Second, the surplus. A lean gain adds about 150 to 250 kcal and grows slowly with the least fat; a standard bulk adds 250 to 500 kcal and suits most people building muscle; an aggressive surplus of 500 or more gains fastest but adds more fat to cut off later. Your target daily intake = TDEE + daily surplus. Bigger is not better here. Muscle can only be built so fast, so past a point the extra calories just become fat. Most people past the true beginner stage do best on a lean to standard surplus.
To project the gain rate, run the energy math in reverse: about 7,700 kcal of cumulative surplus adds roughly one kilogram of bodyweight (about 3,500 kcal per pound). So a standard +375 surplus is about 0.34 kg (0.75 lb) of scale weight per week. Be honest about what that number is: it is total bodyweight, not pure muscle. Muscle is built far more slowly than the raw energy math implies, and the rest of the gain is fat, water and glycogen. Treat the output as a starting point and verify it against your real weight trend over two to three weeks. If you want to fine-tune the whole plan rather than just the surplus, the bulking calorie calculator turns your maintenance into a full macro split.
Why does muscle gain need protein and training, not just calories?
A surplus supplies the energy to grow, but it does not decide how much of the gain is muscle versus fat. Two things steer that split: enough protein and a progressive resistance-training program. Without both, a surplus just makes you heavier. For building muscle, aim for 1.6 to 2.2 grams of protein per kilogram of bodyweight per day (about 0.7 to 1 g per pound) - the widely used sports-nutrition range. Protein is the macro you set first and hold steady while carbs and fats flex with the surplus. Dial yours in with the protein calculator.
Training is the other half. The surplus and the protein are raw material; progressive overload - adding reps, weight or sets over time - is the signal that tells the body to spend that material on muscle rather than store it as fat. A surplus without hard, structured training mostly adds fat, and a hard program without enough calories or protein leaves gains on the table. Higher carbs in a surplus are a feature, not a problem: they fuel the sessions that drive growth.
When should you eat at maintenance or recomp instead?
A surplus is not always the right call. If you are carrying more body fat than you want, or you are new to lifting or returning after a long break, you can often build muscle and lose fat at the same time by eating near maintenance with high protein and hard training - a body recomposition. The body recomposition calculator helps you set that up. Recomp is slower on the scale but it skips the fat you would add in a surplus and the cut you would need afterward.
As a rough guide: if you are already lean and progress has stalled at maintenance, a surplus is how you keep building. If you are higher in body fat, start by getting leaner in a deficit or by recomping near maintenance, then bulk once you are in a leaner starting position. The leaner you start, the more of the surplus goes toward muscle and the longer you can gain before you need to cut.
How do coaches set surplus targets for clients?
Online fitness and nutrition coaches reach for a surplus when a client wants to add size or push a strength number - a lean gaining phase for a physique client, a standard one for a lifter chasing more muscle, an aggressive surplus only for a true hardgainer or a returning beginner. You estimate maintenance, pick the surplus size from the client's training age and how much fat they are willing to add, set the target and the protein floor, then read the two to three week scale trend to decide whether to hold or bump calories. It turns vague advice like "eat more" into a specific daily number a client can actually follow.
The math was never the bottleneck. The friction is running this across a whole client list and re-doing each target as check-ins land. Inside Coachway, calorie and macro targets live on each client, so a surplus is a setting on the client rather than a spreadsheet you rebuild - and protein stays locked while carbs flex with the surplus.
If you are setting gaining targets across a whole client list, see how much faster it is when the numbers live on the client.
No charge today - cancel anytime under Billing.More free calculators: bulking calorie calculator, protein calculator, maintenance calorie calculator, and the full free tools hub. New to the idea? Read what a calorie surplus is.
Calorie surplus calculator FAQ.
What is a calorie surplus?
A calorie surplus is eating more calories than your body burns in a day, which gives it the spare energy to build muscle and add bodyweight. A calorie surplus calculator finds your target by estimating your maintenance calories (TDEE) with the Mifflin-St Jeor equation, then adding a daily surplus on top - roughly 150 to 250 kcal for a lean gain, 250 to 500 for a standard bulk, or 500 or more for an aggressive push.
How big should a calorie surplus be for muscle gain?
For most people a surplus of about 250 to 500 kcal per day builds muscle while keeping fat gain modest. Beginners and those returning from a break can push the higher end and still put much of the gain toward muscle; experienced lifters do better on a smaller 150 to 250 kcal surplus because their muscle-building ceiling is lower and a big surplus mostly adds fat. Bigger is not better here - past a point, the extra calories only become fat you have to diet off later.
How much weight should I gain per week in a surplus?
On a standard surplus most people gain roughly 0.25 to 0.5 kg (about 0.5 to 1 lb) per week of total bodyweight. That figure comes from the rule that about 7,700 kcal of cumulative surplus adds roughly one kilogram (3,500 kcal per pound), run in reverse. It is total scale weight, not pure muscle - early gains also include water and glycogen, and some of it is fat. Muscle itself is built far more slowly than the raw energy math suggests, so judge the trend over two to three weeks.
How much protein do I need to build muscle in a surplus?
The widely used sports-nutrition range for building muscle is 1.6 to 2.2 grams of protein per kilogram of bodyweight per day (about 0.7 to 1 g per pound). Eating in a surplus without enough protein tilts more of the gain toward fat, so protein is the macro you set first and keep steady while carbs and fats flex with the surplus. Spreading it across three or four meals helps you hit the daily total.
Will I gain fat in a calorie surplus?
Some fat gain is normal - you cannot build muscle at a meaningful rate without eating above maintenance, and no macro split makes the gain pure muscle. The point of choosing a lean or standard surplus is to keep the extra small enough that most of the gain is muscle and glycogen, leaving less to cut later. Early scale jumps also include water as carbs go up, so track the trend over two to three weeks rather than reacting day to day.
How do coaches use a calorie surplus calculator with clients?
Coaches use it to set a realistic starting target and an honest gaining timeline before a client's first week, then review weekly check-in data and adjust. It turns "eat more" into a specific number a client can act on. On a coaching platform you set each client a calorie and macro target once, keep protein locked while carbs flex with the surplus, and their app tracks progress against it automatically.
This calculator provides general estimates for education, not medical, dietary, or clinical advice. Calorie needs vary with body composition, health conditions, and activity, and the formulas used are population averages. Consult a qualified professional before making significant changes to your diet, especially if you have a medical condition.
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