watts&timeFiles stay in your browser

Predict a ride

How long will this road take, ridden the way you mean to ride it?

Drop in a GPX from any route planner, or a FIT of a ride you already did, say what you will hold and how you will sit, and read the time — with the band that not knowing your own drag area puts around it, and what a wind from any bearing would cost. Your file is read in your browser and never uploaded.

1The route

A .gpx from any route planner, or a .fit of a ride you already did. It is read in your browser and never uploaded.

2You and the bike
3How aero you are

Typical published figures for each position. They decide most of the answer and nobody has measured their own, so type over any you disagree with.

  • Standing on the pedalsm²
  • Seated, hands on the topsm²
  • Seated, on the hoodsm²
  • Seated, in the dropsm²
  • On the hoods, forearms flatm²
  • On clip-on aerobarsm²
  • Time-trial bike, on the extensionsm²
4The day

Drop in a route to see what it will take.

It comes back as a handful of rows, one per kind of road, with how much of the route is that steep. Set what you plan to hold on each and the time follows. Nothing is stored and nothing is a training plan: it is the physics of one rider on one road, with the parts nobody can know said out loud.

What you'll find out

  • How long it will take. The whole route under your own plan, not an average speed you have to guess at.
  • What kind of road it is. The route gathered by slope: how much is flat, how much is climbing, how much is steep enough to matter.
  • What to hold where. Set the watts and the position for each kind of road and watch the total move; a harder climb costs you on the flat that follows it.
  • What the wind will do. One steady wind from one bearing, ridden into and away from as the road turns, so an out-and-back gives most of it back and a one-way does not.
  • How sure any of it is. The band that a drag area picked off a list puts around the answer, and whether it is the figure this road turns on.
  • What one change is worth. A step of tyre, a kilogram, a lower position, ten watts everywhere you pedal — each priced on this road rather than in the abstract.
  • Where the road actually goes. A map coloured by slope, which is what decides whether a wind helps you or follows you round.

Questions

Which files work?

A .gpx from any route planner, or a .fit from a ride you already did, zipped or not — a ride you have done is a road you can plan on. The route needs elevation in it; a file exported without heights reads as flat, and the page says so rather than answering anyway.

Is my route uploaded anywhere?

The file is read in your browser and never sent. The positions and heights in it go to the server to work out the time, and nothing of them is kept. The map loads its tiles from a map service, which can see the area of the route and nothing more.

How accurate is it?

Accurate about the road, honest about you. The climbing, the distance and the slopes come from the file. The time rests on numbers you typed, and the one nobody knows is their own drag area, so the answer carries the band that puts around it — a few minutes on a flat route, almost nothing on a steep one, and the page says which.

What if I don't know how aero I am?

Pick the position you ride in and it uses a typical published figure, which is what most people would guess anyway, only stated. If you know better, type over it. If you want it measured rather than guessed, ride the road twice and put both files into the compare tool.

Does it know about wind?

Yes, and it is usually the larger of the two doubts. Give it a strength and a direction and the wind is ridden into and away from as the road turns. Give it a strength alone and it tells you what that wind costs whichever way it blows, which is the honest answer days out. Every wind is a cost: a headwind takes more than the same tailwind gives back.

Why is the time quicker than I would really ride?

Because there is no traffic in it, no corner taken slowly, no stopping and no easing off. It is what the road and the watts you stated come to, which is the useful number to compare plans against — not a time you will see on the computer.