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FitCalc vs Omni Calculator: Fitness Calculators Compared (2026)

Omni Calculator is genuinely impressive — over 3,800 calculators across every domain imaginable, with thoughtful formula explanations and active development. Their health and fitness section is solid. FitCalc takes a different approach: fewer tools, all focused on fitness, with an interface built for people who want to get their number and move on. Both are good. The question is whether you want breadth or focus.

Feature Comparison

Feature FitCalc Omni Calculator
BMI calculator Yes Yes — with extensive explanation
TDEE / calorie calculator Yes — multiple formulas Yes — detailed with activity breakdowns
1 Rep Max calculator Yes — multiple formulas Yes — Epley and others
Heart rate zones Yes — Karvonen method Yes — multiple zone systems
Sleep cycle calculator Yes Sleep calculator available
Formula explanations Concise context per calculator Detailed with derivations and examples
Ads Minimal Display ads support the project
Non-fitness calculators Not available 3,800+ covering science, math, finance, cooking
Page speed Fast Reasonable
Macro ratio customization Yes Basic macros available

Where FitCalc wins

Where Omni Calculator wins

The Verdict

Omni Calculator is a legitimately excellent tool with impressive depth and breadth. For fitness calculations, both sites cover the essentials well. FitCalc's advantage is focus and speed — it's built for fitness and nothing else, so the interface is cleaner for that purpose. If you need calculators beyond fitness, Omni is the clear choice. If fitness is all you need, either works well.

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Frequently Asked Questions

Is Omni Calculator free?

Yes, Omni Calculator is free and ad-supported. FitCalc is also free with minimal advertising.

Which has better formula explanations?

Omni Calculator typically provides more detailed educational content with formula derivations. FitCalc focuses on getting you the answer quickly with enough context to interpret it.

Does FitCalc have any calculators Omni doesn't?

FitCalc's running pace calculator — which includes finish time estimates from pace, or pace from target finish time — covers some angles not directly available on Omni. But Omni's overall health calculator catalog is larger.

Other Comparisons

vs MyFitnessPal See comparison vs Calculator.net See comparison