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Weekly volume builders that respect the 10% rule, 5k-to-marathon equivalent pace maths, honest load and rest-day checks, season countdowns, team budgets, shoe-replacement timing and plain-spoken training guides — type your sports question and get a straight answer in seconds, with real numbers you can plan a week around. The full detailed report costs less than a coffee: $2.95.

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Race Time Predictor: Equivalent 5k, 10k, Half & Marathon Times

A training diary and stopwatch on a dark wooden bench at dawn, a runner's shoes laced beside it, cool charcoal light with a lime-green glow from the track lights beyond — sports training planning guide

One good race result is a goldmine of information — if you know how to read it. This predictor takes the time and distance of your most recent race or hard time trial and projects what it means at 5k, 10k, half marathon and marathon using the Riegel endurance curve, the same formula behind most pace calculators. Time scales with distance to the power 1.06, which is why a 25-minute 5k projects to roughly 52 minutes for 10k rather than a naive 50. The verdict spells out which projection to trust most — usually the half marathon from a 5k or 10k input — and reminds you that every prediction assumes you train appropriately for the distance being predicted.

⚡ Free instant check

Turn one recent race result into honest equivalent times for 5k, 10k, half marathon and marathon — the standard Riegel endurance curve, with your current pace per kilometre spelled out.

❓ Race Time Predictor: Equivalent 5k, 10k, Half & Marathon — FAQ

How accurate are equivalent-time predictions?

They are honest estimates, not promises. The Riegel curve is built on thousands of real race results and works well for endurance-trained runners, but weather, course profile, training block and race-day execution move the real result by minutes in either direction.

Which projection should I trust most?

Usually the one closest to your input distance. A half-marathon projection from a 5k or 10k result is typically the most reliable; the marathon projection assumes you build the long-run base the distance demands, so treat it as a stretch goal rather than a plan.

Can I use a training run instead of a race?

You can, but the prediction will overstate your fitness — casual runs do not produce race effort. Use a real race or a hard, race-paced time trial, and re-test every 6-10 weeks of consistent training to track whether the plan is working.

More plan your training tools

Weekly Training Volume Builder: The 10% RulefreeTraining Load Score: Acute-to-Chronic Ratio CheckfreeSeason Planning Calendar: Race Countdown & TaperfreeRest Day Planner: Honest Recovery MathsfreeStrength Sessions per Week: How Many You Really Needfree

🏃 All sports tools

Every tool answers instantly from our own knowledge and calculators — no AI wait, no account. Honest maths and plain guidance, always educational and never medical: training is a long game of consistent, sensible weeks, and these tools exist to keep your plan realistic and your body in one piece — not to sell you a miracle programme. Results are estimates and reflections, not diagnoses or prescriptions, and nothing you type is stored. Want the deeper, personalised version? Each has a $2.95 full report.

🗓️ Plan Your Training
Weekly Training Volume Builder: The 10% RulefreeRace Time Predictor: Equivalent 5k, 10k, Half & MarathonfreeTraining Load Score: Acute-to-Chronic Ratio CheckfreeSeason Planning Calendar: Race Countdown & TaperfreeRest Day Planner: Honest Recovery MathsfreeStrength Sessions per Week: How Many You Really Needfree
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💧 Recover & Fuel
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Educational information only — not medical, coaching, nutritional or physiotherapy advice, and never a guarantee of outcomes. Bodies, training ages and local costs vary widely: the tools give estimates and reflections, not prescriptions. If you are returning from injury, carrying a health condition or feeling something that is not right, talk to a qualified professional — they are always the right next step. Refunds honoured.
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