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Your clean starting line

Running calculators, training articles, and book guides to run better.

RunCalcs is a distraction‑free hub for running calculators, training articles, and curated books so you can plan workouts, dial in pacing, and keep improving.

Featured Articles

Quick, evidence‑informed reads you can act on today.

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Recommended Books

Trusted titles to deepen your understanding.

View All Books

Popular Calculators

Get precise paces and realistic targets.

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Pace Calculator

Convert between pace, speed, and finish time.

Open pace calculator km / mile

Race Time Predictor

Predict finish times from your recent race.

Open race predictor 5K → Marathon

Heart‑Rate Zones

Calculate easy, tempo, and interval zones.

Open HR zone tool %Max or LTHR

VO₂ Max / VDOT

Estimate aerobic fitness and training paces.

Open VO₂ / VDOT Jack Daniels

Splits Planner

Plan even or negative splits for any distance.

Open splits planner Negative / Even

Recovery & Rest

Guidelines for bounce‑back days and weeks.

Open recovery guide Smart rest

Companion application

Take Runcalcs on the go with our iOS app.

Download on the App Store

Frequently asked questions

What makes RunCalcs different from other running sites?

RunCalcs keeps the focus on evidence-based advice and accurate running calculators. Instead of overwhelming you with ads or pop-ups, the site highlights the most useful tools and reading so you can take action quickly.

Are the calculators suitable for new and experienced runners?

Yes. Each calculator includes guidance, examples, and pacing tables so beginners understand the results while experienced runners can move straight to the numbers they need for training and race planning.

How often are the training articles and book picks updated?

The editorial team reviews new science and proven coaching practices regularly. When better research or recommendations become available, the collections are refreshed to keep the advice current.