Running Pace, Speed & Race Time Calculator

The Running Pace & Race Time Calculator is built for quick, confident decisions before a workout or a race. Pick metric or imperial at the top and everything you see—distance choices, pace labels, equivalent race times, and split plans—will mirror that unit. If you choose metric, you’ll only see kilometers, min/km, and km/h. If you switch to imperial, the interface and the results flip to miles, min/mi, and mph. That way there’s no mental math required and no mixed output that can confuse you on the start line.

Enter any pair of inputs. If you know your Goal Time, select a distance and type the finish time; the page calculates the matching pace and speed. If you know your target Pace, enter that instead and the calculator returns an expected finish time. Both methods work the same behind the scenes: time divides by distance to get pace, and distance divides by time to get speed. The difference is simply which field you find easier to think about when planning training runs, workouts, or race strategy.

Below the main numbers you’ll find a compact table of equivalent times for common events. In metric mode, times are shown for 1 km, 5 km, 10 km, half marathon, and marathon. In imperial mode, times are shown for 1 mile, 5 miles, 10 miles, half marathon, and marathon. These equivalents let you sanity-check a plan: if your 10 km target implies an unrealistic marathon, you’ll notice instantly and can tune the inputs. For runners who train by pace rather than finish time, the equivalents also help translate one workout style into another—tempo, long run, or progression—without reaching for a separate chart.

• Use even splits if you feel uncertain or you’re racing on a hilly course with variable conditions.
• Try a small negative split (about one percent faster in the second half) when you want to stay conservative early.
• Pick the three-percent option for goal races where you’re confident and want a stronger close.

The built-in predictor turns a recent performance into a target for a different distance. Type something like “10k 00:48:00” or “5 mi 00:40:00,” choose your new distance, and the page applies a standard scaling exponent so the time adjusts realistically as the race gets longer or shorter. Prediction is a guide, not a promise. Wind, heat, humidity, hills, altitude, terrain, and fueling will all move the final result. Use the estimate to set an initial goal for training and then refine it after a few key sessions—long tempos, marathon-pace runs, or tune-up races—confirm the shape you’re in.

Because the Running Pace & Race Time Calculator keeps outputs in a single system, it’s globally understood and easy to read on a phone. You won’t see min/km next to mph or a mile split inside a kilometer plan. That simplicity is intentional; it mirrors how watches, treadmills, and track markings are configured in the real world. When you change the unit selector, placeholders update, pace labels switch, custom distance badges toggle between “km” and “mi,” and the entire results block re-renders so nothing is ambiguous.

Practical pacing tips: hold back during the first kilometer or first mile, especially in crowded starts. Breathe rhythmically and aim for relaxed form—shoulders down, quick cadence, gentle arm swing. If you’re using a negative split, think of the first half as your setup and the second half as the execution. On rolling courses, pace by effort uphill and let gravity do the work downhill, checking the average only every few minutes. If you run by heart rate or power, keep those targets primary and use the pace here as a cross-check. For treadmill sessions, the speed field in km/h or mph maps neatly to the console readout.

Training context matters. A marathon plan built around long aerobic volume will not deliver the same 5 km performance as a block focused on short intervals and VO₂max work. Similarly, a fast 5 km doesn’t guarantee a breakthrough marathon without the long-run stamina to back it up. That’s why the calculator shows equivalents and split options rather than a single number in isolation. Use those pieces together to set a realistic target, then practice that target on race-pace workouts so it feels familiar. The more you rehearse the rhythm of the pace, the easier it is to hold on the day.

Fueling and hydration deserve a mention, too. For efforts under an hour, water and a simple warm-up often suffice. For longer events, plan small carbohydrate intakes at predictable intervals and test them during long runs. Shoes, socks, lacing, and weather-ready layers also matter more than people think. The best calculator can’t fix a blister after 10 miles, but a few dress rehearsals will. Keep your approach simple, respect your own data, and let the Running Pace & Race Time Calculator translate goals into clear, unit-pure numbers you can trust.

The converter uses basic relationships: pace = time ÷ distance, speed = distance ÷ time. The predictor scales a performance with a commonly used exponent near 1.06 so the curve between two distances matches what many runners observe from 3 km through the marathon. The split planner divides the course into two halves, nudging the second half one to three percent faster and redistributing those seconds evenly over each kilometer or mile. All math runs locally in your browser for instant feedback and privacy; no data is stored.