Pregnancy Calorie Calculator (& Protein)
How this is calculated
This calculator starts with the Mifflin-St Jeor equation, one of the most widely used formulas for estimating basal metabolic rate (BMR) from weight, height, age and sex, then multiplies it by your activity level to get an estimated maintenance calorie level — the same math used in general adult calorie calculators.
On top of that baseline, we add the typical extra calories associated with each trimester: none in the first trimester (when needs are close to pre-pregnancy levels for most people), around 340 kcal/day in the second, and around 450 kcal/day in the third, plus an additional allowance if you're expecting twins. Protein follows a similar pattern — a baseline of about 0.8g per kilogram of body weight, plus roughly 25g more per day once you're pregnant.
These trimester add-ons are general guidance figures, not a measurement of your individual metabolism — they're a reasonable starting range, not a target to hit exactly every day.
Common edge cases and things to know
If you're following a restrictive diet, managing gestational diabetes, dealing with nausea that limits what you can eat, or you started pregnancy at a notably low or high weight, your real needs may differ meaningfully from this general estimate — a registered dietitian or your OB/midwife can tailor a plan to your specific situation.
Twin and higher-order multiple pregnancies generally need more calories and protein than a singleton pregnancy at the same stage, which is why the twins option adds extra to both figures above. Activity level is also a rough self-report category, and true energy expenditure can vary quite a bit within each level.
First-trimester nausea can make it genuinely hard to eat consistently, and that's normal — the good news is that extra calorie needs in the first trimester are minimal for most people anyway, so there's usually little pressure to hit a specific number early on. Later in pregnancy, needs can also shift with things like carrying multiples, unusually high or low pre-pregnancy weight, or a physically demanding job, all of which this calculator's simple activity-level dropdown can't fully capture.