There is a particular kind of confidence that comes from seeing the actual figure. Run your figures through the marathon time predictor — it takes less than a minute, and it changes conclusions surprisingly often.
Banks, accountants and consultants all work with the same underlying logic. Your inputs stay on your device — there is no server side to this tool at all.
What this tool measures
For medical or competitive precision, get a lab test with a spirometer. Marathon time predictor turns training data into concrete targets — 1RM for the strength program, marathon pace, VO2max for endurance. Allows 30–40 minutes under threshold, which builds lactate tolerance — the key adaptation for middle and long distances. Marathon time predictor gives the numbers, but the discipline to follow them week after week is yours.
Without numbers, training is guesswork; with numbers, you get progress it is possible to gauge week over week. Train in cycles (4–6 week mesocycle, 1 deload week).
What the calculator does with your input
Third: ignoring progressive overload. Fourth: computing 1RM from >8 reps — accuracy drops sharply.
Listen to the body — for pain (not muscle soreness) cut volume by 30%. Second: chasing percentages with bad form — 90% of 1RM with poor technique injures. When unsure of 1RM, use a submaximal test (3–5 reps at 85–90%) instead of a true max. Log every session — weight, reps, RPE.
Common: neglecting recovery (24–48 hours between heavy sets on the same muscle).
The rule the tool follows
Marathon time predictor uses the same equations professional coaches use, and returns numbers ready to program. For running — after a controlled 5k or 10k test. Log, recompute, adjust — that's the recipe for long-term growth. Sports formulas are backed by decades of research — Epley for 1RM, Riegel for race pacing, ACSM for calories and heart-rate zones.
Use Marathon time predictor every 4–6 weeks to refresh the program. Formulas (Cooper, Bruce protocol, 5k time) are ±10% exact.
Good times to run the numbers
Tempo is 15–30 seconds per km slower than race, at 80–85% max HR. State-level details may vary.
How this calculation applies in United States: Straight to the numbers — here is how Marathon time predictor behaves under US rules, units and pricing conventions.
When this number matters
- Local notes: Numbers on this page reflect US practice — dollars, imperial units, and federal defaults where applicable. State-level details may vary.
- Units of quantify: US uses imperial: miles, pounds, °F, US gallons, feet/inches. Note that an US gallon (3.785 L) is different from an UK imperial gallon (4.546 L) — every time confirm which.
- Electrical supply: Mains is 120 V / 60 Hz, Type A/B plugs. 240 V circuits exist for high-load appliances (dryer, oven).
- Currency & format: US dollar (USD, $). No decimal separator for thousands — use commas ($1,000.00).
- VAT / sales tax: The US has no federal VAT. Instead, each state applies its own sales tax (0% in Oregon, Delaware, Montana, New Hampshire; up to 7.25% base in California) plus city/county surcharges that can push the effective rate above 10%. Sales tax is typically added at checkout, not included in the sticker price.
Pointers before you commit
Between tests, follow progress via reps at working weight — if 5×5 at 80 kg feels lighter than 4 weeks ago, 1RM has grown. Every figure above applies to United States specifically and is reviewed when the rules change.
That means the output can be used directly with an accountant, lender or employer in the US without converting anything. For strength — recompute 1RM after a safe test (3–5 reps near max).
Mistakes worth dodging
No more than every 8–12 weeks for the same lift. Example: at 10 kg for 75 reps on bench press, Marathon time predictor projects your 1RM. For cardio — after a VO2max or Cooper test. Numbers on this page reflect US practice — dollars, imperial units, and federal defaults where applicable.
The one-minute summary
The calculation is only the beginning — the value is in the decision you make afterwards. Bookmark this page and come back when conditions change; the numbers will move, the logic won't.
the United States-specific questions
Is this Marathon time predictor valid for the United States?
Yes. It uses US dollar (USD, $) and imperial (miles, lb, °F, US gallons), and any tax or contribution reference follows IRS rules.
Which units and number format are used?
Amounts display as $1,234.56 and quantities in imperial (miles, lb, °F, US gallons) — the official convention in the US.
Which pension and tax model is assumed?
Social Security + 401(k) / IRA. The tax framework is federal brackets 10–37% plus state tax; no VAT, sales tax instead.