Two precision instruments for the road and the track — all running live in the box above. Fill in your numbers and watch every result update instantly, right in your tab. Nothing is uploaded, nothing is stored.
Enter the distance you drove and the fuel it took, and get your economy in every unit that matters: litres per 100 km, kilometres per litre, US miles per gallon and imperial MPG. Add a fuel price and it also works out trip cost, cost per kilometre and cost per 100 km — plus an honest efficiency rating.
Example
450 km on 32 l · fuel at $1.60/l…
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7.11 l/100 km · 14.06 km/l · 33.1 mpg US · trip cost $51.20.
Use it for tank-to-tank checksroad trip budgetscar comparisonfleet tracking
Built for runners: pick a distance and a pace per kilometre, and it returns the finish time, your speed, and projections for the classic race distances — 5K, half marathon and marathon — at exactly the same effort. Perfect for setting treadmill speed or splitting a race evenly.
Example
10 km at 5:30 /km…
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Finish 55:00 · 10.91 km/h · marathon projection ≈ 3:52:04.
Use it for race goalstreadmill settingseven splitstraining zones
Conventions · l/100 km = fuel ÷ distance × 100 · mpg US = 235.215 ÷ (l/100 km) · mpg imperial = 282.481 ÷ (l/100 km) · 5K = 5 km · half = 21.0975 km · marathon = 42.195 km · pace projections assume flat, constant effort
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This page has no backend and no database. Every number you just watched was computed by JavaScript inside your own browser tab — your distances, fuel and paces never traveled a single centimeter of cable. Close the page and they're gone for good.
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Questions
Asked often, answered plainly.
( 02 )
How are fuel economy units related?
L/100 km and MPG are inversely related: lower L/100 km is better, while higher MPG is better. The exact conversions are MPG (US) = 235.215 ÷ (L/100 km) and MPG (imperial) = 282.481 ÷ (L/100 km). Kilometres per litre is simply distance divided by fuel used.
What does the Pace Calculator assume?
A constant pace on flat ground. Real races include hills, fatigue, aid stations and crowds, so treat the projections as targets rather than promises — most runners slow by a few percent over a full marathon.
Which race distances are used?
The official road distances: 5K = 5 km, 10K = 10 km, half marathon = 21.0975 km and marathon = 42.195 km.
Is the data I enter saved anywhere?
No. IrisTool has no backend and no database. All calculations run inside your browser tab and disappear the moment you close or refresh the page. Your numbers are never transmitted, stored or logged.