About RunPaceKit

What it does

RunPaceKit is a set of running calculators with one job: turn the numbers you already have — a distance, a time, a pace — into the numbers you need next. The pace calculator solves for whichever of distance, time or pace you are missing. The race split calculator breaks a target time into a lap-by-lap table you can print and carry. The negative split calculator shows what a race would look like if the second half ran faster (or slower) than the first, with the total time held constant. The guides explain the arithmetic behind each tool.

Who it is for

Recreational runners who want a pacing plan without an account, a sync, or a coaching subscription. If you have ever wanted a clean sheet of split times to tape to a race band, or a quick answer to "what pace is 50 minutes for 10 km in miles?", this site is built for that moment.

Principles

• Calculations stay in your browser. No distance or time you enter is sent to a server. There is nothing to sign up for and nothing to log into.
• Exact math, honest rounding. Internally everything is meters and seconds with exact constants; rounding happens only for display, and the methodology page states every rule.
• Honest limits. The calculators produce pacing scenarios from your inputs. They do not predict fitness or guarantee outcomes, and the pages say so plainly.
• Minimal data. No analytics at launch, no advertising enabled, and a single saved plan that lives only in your own browser storage. Details in the privacy policy.

Who runs it

RunPaceKit is operated by RunPaceKit Editorial. The site launched with the calculation set described above and keeps a public formula version (1.0.0) so any future change to the math is traceable. If you spot an arithmetic problem or an unclear explanation, the contact page lists how to reach us.

What it is not

It is not a training platform, a social network, or a source of medical advice. It does the arithmetic; you bring the running.