Pace Calculator
This Pace Calculator helps runners and coaches compute pace, convert pace units, and estimate finish times from pace or time and distance. It supports common running units (kilometers and miles) and presents results as seconds-based calculations to avoid rounding ambiguity.
Use the appropriate mode for your need: provide time and distance to get pace, provide pace and distance to estimate time, or convert pace units and derive equivalent speed. Results are intended for planning and pacing; actual race conditions and physiology will affect outcomes.
Governance
Record e5638d73eea6 • Reviewed by Fidamen Standards Committee
Compute pace (seconds per km and per mile) when you provide total time and distance.
Inputs
Results
Pace per kilometer (seconds)
186.4114
Pace per mile (seconds)
300
| Output | Value | Unit |
|---|---|---|
| Pace per kilometer (seconds) | 186.4114 | s/km |
| Pace per mile (seconds) | 300 | s/mi |
Visualization
Methodology
Calculations use SI-consistent distance measures (meters) and seconds for time to maintain numeric precision before converting to user-facing units. One mile is taken as exactly 1,609.344 meters following international conversion conventions.
Where unit choices matter, conversions are applied before arithmetic to limit floating-point error. When reporting to users, times are derived from seconds and then formatted for readability by the UI layer.
Accuracy and reporting follow measurement best practices. For numeric stability and reproducibility we reference standards for units and metrology such as NIST and ISO, and for software correctness we follow IEEE guidance on numerical computing.
Worked examples
Example: 5 km in 25:00 results in pace_per_km = 300 s (5:00 per km) and pace_per_mile ≈ 482.9 s (8:02.9 per mile).
Example: A 6:00 min/mile pace (pace_unit = min_per_mile, pace_minutes=6) converts to ≈ 3:44.1 min/km and speed ≈ 10.0 km/h.
F.A.Q.
Which units should I use?
Choose the unit system you train in. Use kilometers for metric races and miles for imperial. The calculator accepts either and converts internally to meters for computation.
How accurate are the results?
Numerical results follow exact conversion constants and typical floating-point precision. Real-world pacing will vary with terrain, weather, and physiology. Treat results as planning estimates; verify against GPS/watch telemetry. See citations for measurement standards.
Why do seconds appear as decimals?
Intermediate calculations use seconds as decimals to preserve precision; the UI or export layer should format seconds into minutes:seconds for human readability.
Can I use this for erg (rowing) splits?
Yes, the same time/distance arithmetic applies. For sport-specific split conventions (e.g., seconds per 500 m), convert input or output units accordingly by selecting the appropriate pace_unit and distance.
Sources & citations
- National Institute of Standards & Technology (NIST) - Units and Standards — https://www.nist.gov
- International Organization for Standardization (ISO) - Quantities and units — https://www.iso.org
- IEEE - Recommended Practices for Numerical Computing — https://standards.ieee.org
- Occupational Safety and Health Administration (OSHA) - Measurement and Reporting Guidance — https://www.osha.gov
- CDC — Body Mass Index (BMI) Categories — https://www.cdc.gov/bmi/adult-calculator/bmi-categories.html
- NIH — National Institutes of Health Metabolic Research — https://www.nih.gov/
- ACSM — American College of Sports Medicine Guidelines — https://www.acsm.org/
- PubMed — Mifflin-St Jeor Equation (PMID: 2305711) — https://pubmed.ncbi.nlm.nih.gov/2305711/
Further resources
Versioning & Change Control
Audit record (versions, QA runs, reviewer sign-off, and evidence).
Record ID: e5638d73eea6What changed (latest)
v1.0.0 • 2025-11-22 • MINOR
Initial publication and governance baseline.
Why: Published with reviewed formulas, unit definitions, and UX controls.
Public QA status
PASS — golden 25 + edge 120
Last run: 2026-01-23 • Run: golden-edge-2026-01-23
Versioning & Change Control
Audit record (versions, QA runs, reviewer sign-off, and evidence).
What changed (latest)
v1.0.0 • 2025-11-22 • MINOR
Initial publication and governance baseline.
Why: Published with reviewed formulas, unit definitions, and UX controls.
Public QA status
PASS — golden 25 + edge 120
Last run: 2026-01-23 • Run: golden-edge-2026-01-23
Engine
v1.0.0
Data
Baseline (no external datasets)
Content
v1.0.0
UI
v1.0.0
Governance
Last updated: Nov 22, 2025
Reviewed by: Fidamen Standards Committee (Review board)
Credentials: Internal QA
Risk level: low
Reviewer profile (entity)
Fidamen Standards Committee
Review board
Internal QA
Entity ID: https://fidamen.com/reviewers/fidamen-standards-committee#person
Semantic versioning
- MAJOR: Calculation outputs can change for the same inputs (formula, rounding policy, assumptions).
- MINOR: New features or fields that do not change existing outputs for the same inputs.
- PATCH: Bug fixes, copy edits, or accessibility changes that do not change intended outputs except for previously incorrect cases.
Review protocol
- Verify formulas and unit definitions against primary standards or datasets.
- Run golden-case regression suite and edge-case suite.
- Record reviewer sign-off with credentials and scope.
- Document assumptions, limitations, and jurisdiction applicability.
Assumptions & limitations
- Uses exact unit definitions from the Fidamen conversion library.
- Internal calculations use double precision; display rounding follows the unit's configured decimal places.
- Not a substitute for calibrated instruments in regulated contexts.
- Jurisdiction-specific rules may require official guidance.
Change log
v1.0.0 • 2025-11-22 • MINOR
Initial publication and governance baseline.
Why: Published with reviewed formulas, unit definitions, and UX controls.
Areas: engine, content, ui • Reviewer: Fidamen Standards Committee • Entry ID: b914c847675c