Free, science-based fitness tools built for adults over 40 who are done with gimmicks.
MyFitFormulas started the way a lot of useful things do: out of personal frustration. Our founder, Joe Grizzy, hit his 40s and realized that every fitness calculator on the internet was either buried in pop-up ads, designed for 22-year-old gym bros, or just flat-out wrong. He didn't need a six-pack transformation plan. He needed a straightforward answer to a straightforward question: How many calories should I eat to stop gaining weight?
So he built the answer himself. What started as a single spreadsheet became a set of tools, then a website, and eventually what you see today: a collection of free, no-BS fitness and nutrition calculators built specifically for adults over 40 who have real jobs, real responsibilities, and zero patience for fitness industry nonsense.
Every calculator on this site is powered by peer-reviewed research—not influencer marketing. We didn't invent these formulas. Scientists did. We just made them accessible.
Our Maintenance Calorie Calculator and BMR Calculator use the Mifflin-St Jeor equation, which research has consistently shown to be the most accurate method for estimating basal metabolic rate in adults. It accounts for your age, weight, height, and sex to give you a realistic starting point—not a fantasy number pulled from a generic chart.
Our Body Fat Calculator uses the U.S. Navy circumference method, a validated approach that estimates body composition from simple tape measurements. Is it as precise as a DEXA scan? No. Is it accurate enough to track trends and make informed decisions without spending $150 per visit? Absolutely.
From our Macro Calculator to our One-Rep Max Calculator, every tool follows the same principle: use the best available science and present it without the clutter. No upsells hiding behind your results. No "premium unlock" to see your own numbers.
MyFitFormulas is built for adults over 40 who want to take their health seriously without turning it into a second career. You're probably juggling a demanding schedule, maybe raising kids or managing a household, and you don't have hours to spend researching nutrition science or decoding supplement labels.
You might be dealing with a metabolism that doesn't work the way it used to. Maybe you've noticed that the eating habits that kept you lean at 30 are adding pounds at 45. Or you've tried one of those cookie-cutter programs and realized it was designed for someone half your age.
That's exactly who we had in mind. Our tools give you real data about your body—your actual maintenance calories, your estimated body fat, your macronutrient targets—so you can make informed decisions without guesswork. Whether your goal is losing weight, building muscle, or just understanding where you stand, we give you a clear starting point based on real science.
Most fitness sites exist to sell you something. We exist to give you something: accurate information, presented clearly, with zero strings attached. Every core calculator on this site is completely free. No account required. No email gate. No bait-and-switch.
We do offer a paid plan—The Anti-BS Healthy Living Plan—for people who want AI-powered coaching, personalized meal ideas, and deeper guidance. But the foundation of this site, the calculators and the educational content, will always be free. Because knowing your own numbers shouldn't cost you anything.