Our Story

RunCalc has existed since 2010 — back when the web was full of running calculators buried behind registration walls or cluttered with intrusive ads that obscured the one number you actually needed: your race pace.

We rebuilt the site from the ground up with a simple belief: a calculator should load fast, give you the right answer immediately, and get out of your way. No email required. No "premium tier." No dark patterns.

Over time, runners kept asking us for more — can you add a BMI calculator? A mortgage one? A time zone converter? So we did. Then 10 more. Then 100. Today RunCalc covers eight categories: running, health & fitness, finance, math, conversions, date & time, everyday life, and science. Every single tool is free.

We also believe calculators should work for everyone, everywhere. That's why we've localised every major tool into 33 languages — not just translated, but adapted for local units, currencies, and number formats. Whether you're in São Paulo, Seoul, or Stockholm, RunCalc speaks your language.

What We Stand For

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    <h3>Accuracy</h3>
    <p>
      Every formula is sourced from peer-reviewed research, official standards, or
      established industry practice. We document our sources and review calculations
      when new data emerges. If you spot an error, <a href="/contact/">tell us</a> — we'll fix it fast.
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    <h3>Speed</h3>
    <p>
      RunCalc is a static site. No server round-trips, no heavy JavaScript frameworks,
      no tracking scripts blocking your result. Every calculator runs entirely in your
      browser and responds in milliseconds. We obsess over Core Web Vitals so you don't
      have to wait.
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    <h3>Privacy</h3>
    <p>
      Your inputs never leave your device. All calculations happen locally in your
      browser — we never see the numbers you type. We only load analytics and advertising
      cookies with your explicit consent. You can use every single calculator with zero
      cookies enabled.
    </p>
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    <h3>Accessibility</h3>
    <p>
      RunCalc is built for everyone. All calculators pass WCAG 2.1 AA standards, support
      keyboard navigation, work with screen readers, and respect your system's reduced-motion
      and high-contrast preferences. Dark mode is available on every page.
    </p>
  </div>

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What You'll Find Here

RunCalc is best known as a running calculator — but it's grown into much more. Here's a taste of what's available:

• 🏃 Running calculators — Pace calculator, VDOT, race time predictor, marathon pace, half marathon pace, training zones, VO₂ max, treadmill converter, negative split, and more.
• 💪 Health & fitness — BMI, BMR, TDEE, body fat, macro calculator, calorie deficit, ideal weight, heart rate zones, and sleep calculator.
• 💰 Finance — Mortgage, compound interest, loan payoff, retirement planner, salary, investment returns, and debt-to-income ratio.
• 🔢 Math — Percentage, fractions, standard deviation, quadratic equations, probability, matrix operations, and 40+ more.
• 🔄 Unit conversions — Metric to imperial, temperature, currency, cooking measures, data sizes, and dozens of niche converters.
• 📅 Date & time — Age calculator, date difference, days until, time zone converter, business days, and pregnancy due date.

Browse all calculators →