Overview
Sixpacks.fit is an independent website that offers free, browser-based fitness calculators. This page explains how we choose what to build, how we research and verify our content, and how we keep things accurate and honest. We believe in being transparent about what we do and, just as importantly, what we do not do.
What We Publish
Our content consists primarily of fitness and health calculators. These are interactive tools that run entirely in your browser using JavaScript. We currently offer 12 calculators covering body fat percentage, daily calorie needs, macro targets, BMI, and other common fitness metrics. Each calculator is based on published, publicly available formulas from recognized sources. We also publish informational articles related to fitness, nutrition, and body composition to help users understand what the numbers mean and how to interpret them.
We do not provide medical advice, diagnosis, or treatment recommendations. Our calculators produce estimates, not clinical measurements. Always consult a qualified healthcare professional for advice specific to your situation.
Topic Selection
We choose what to build based on what people are actually looking for. Common fitness questions like "How much body fat do I have?" or "How many calories should I eat?" are the kinds of problems our calculators aim to address. We pay attention to search trends, user feedback, and gaps in existing free tools. If a formula is well-established and widely used in the fitness community but no free, easy-to-use calculator exists for it, that is a good candidate for us to build.
Research and Sources
Every calculator we build is based on a published formula or methodology from a recognizable source. Examples include:
- The U.S. Navy body fat circumference method
- The Mifflin-St Jeor equation for estimating resting metabolic rate
- Standard BMI calculations from the CDC and WHO
When we write accompanying articles or explanations, we rely on publicly available information from organizations like the Centers for Disease Control and Prevention (CDC), the World Health Organization (WHO), the National Institutes of Health (NIH), and peer-reviewed research published in reputable journals. We cite our sources within the content so you can verify them yourself.
Formula Implementation and Verification
When we implement a calculator, the process works like this:
- Identify the source formula. We locate the original publication or recognized methodology behind the calculation.
- Implement it in JavaScript. We write the code to perform the calculation client-side, meaning it runs in your browser and no data is sent to a server.
- Test with known inputs. We check our calculator against example calculations from the original source or from trusted references.
- Compare with existing tools. We cross-check our results against other established calculators that use the same formula.
Factual Verification
For informational content (articles, explanations, definitions), we cross-reference claims with at least two independent, credible sources. If we cannot find a second source confirming a claim, we either attribute it to its single source explicitly or we do not include it. We prefer primary sources (research papers, official health organizations) over secondary sources (blog posts, fitness magazines) when both are available.
Human Review
Every piece of content published on Sixpacks.fit is reviewed by the site operator before it goes live. This includes checking the calculator output against expected results, reviewing the accompanying text for clarity and accuracy, and verifying that sources are properly cited. Because we are a small, independently operated site, this review is performed by one person rather than a large editorial team. We believe this is better than having no review at all, and we are honest about the fact that it is not the same as review by a medical professional.
Updates and Maintenance
Fitness formulas and guidelines do not change frequently, but they do change occasionally. We periodically review our calculators to ensure the formulas we use are still the current standard. When we find that a newer or better formula exists, we evaluate whether to update our calculator and, if we do, we note the change on the calculator page.
Corrections
If we discover an error in a calculator or in our content, we fix it as quickly as possible. When we make a correction that could have affected results you previously saw, we add a note to the page explaining what was wrong, when it was fixed, and what changed.
If you believe you have found an error, please contact us at team.sixpacks.fit@gmail.com and we will investigate.
User Safety and Medical Disclaimer
Our calculators are tools for estimating fitness metrics. They are not medical devices, and the numbers they produce are not medical advice. Here is what that means in practice:
- Estimates, not measurements. A body fat calculator that uses circumference measurements will give you an estimate. It will not be as precise as a DEXA scan or hydrostatic weighing.
- Conservative by design. Where formulas have different variants, we generally choose the more established and widely accepted version.
- Consult a professional. If you are making decisions about your diet, exercise program, or health based on numbers from our calculators, talk to a doctor, registered dietitian, or qualified fitness professional first.
- Not for clinical use. Our tools are designed for general fitness awareness, not for diagnosing conditions or prescribing treatment plans.
Transparency About Limitations
- We are an independent website, not affiliated with any medical organization or certification body.
- Our calculators use published formulas, but the formulas themselves have limitations.
- We do not have a medical review board. Content is reviewed by the site operator, not by licensed physicians or registered dietitians.
- We do not collect personally identifiable information through our calculators. All calculations happen in your browser.
Contact
If you have questions about our editorial process, want to report an error, or have suggestions for new calculators, reach out to us at team.sixpacks.fit@gmail.com.
Changes to This Policy
If we make material changes to this editorial policy, we will update the date below and briefly describe what changed.
Last updated: August 2026