Why the Range on the Screen Is an Estimate, and How to Read Your Own

Published October 23, 2026 · Last reviewed October 23, 2026

What the number is actually made of

Think of two separate readings sitting behind one figure. The first is how much stored energy the battery says it has. That one is a measurement, and the percentage display is the simplest view of it. The second is how many miles each unit of that energy will buy, and that one is a forecast.

How the forecast is built is not something this page can state for your car. Depending on the model, the software release and your display settings, the car may lean on a fixed reference figure, on your recent driving, or on a route you have entered. Your owner’s manual describes what yours does, and you can usually switch the display between percentage and distance. The takeaway is simple: a percentage tells you how much energy you have; a distance tells you how far a guess says it will go. Neither is wrong when they seem to disagree.

Why the forecast moves

Everything that changes the energy cost of a mile changes the answer, and most of it has nothing to do with the car being faulty. None of these effects is quantified here, because the size depends on your model, your tires and your roads. The direction is what matters.

• Higher speed costs more energy per mile than lower speed.
• Cold or hot weather raises the load from cabin heating or cooling, and a cold battery is less willing to give and accept power.
• Headwind, hills and a loaded car cost more than a calm, flat, empty run.
• Low tire pressure raises rolling resistance, which is why a pressure check belongs in the same routine.
• Short stop-start trips spend a larger share of their energy warming things up.

The same road on a mild day and on a freezing, windy day are different journeys, even though the screen drew the same line on the map.

Replace the guess with your own data

The fix is to measure the one input the car has to guess. Pick a route you already drive every week, ideally 20 to 40 miles, and compare it with itself. Menu names and locations move between software releases, so look for an energy or trip view on your touchscreen, often called Energy, and for a trip meter you can reset.

Action

Reset a trip meter at the start of a repeated route and, at the end, write down the distance, the battery percentage points used and the conditions (temperature, climate on or off, passengers).

Why it helps

Distance and percentage points used are numbers the car actually measured. Dividing one by the other gives your consumption without relying on the forecast.

Verification

Do it on three separate days. If the three results are close, the route is a good yardstick. If one is far off, check what was different that day.

Action

Take the worst of the three as your planning figure, and compute remaining distance from the percentage left, not from the distance on the screen.

Why it helps

Planning on your worst recent result builds in the bad-weather day without you having to guess its size.

Verification

On your next drive of that route, the plan should finish with energy to spare. If it does not, your yardstick was too optimistic: use a worse run.

Action

Use a longer route or average several runs if the percentage changes in whole steps that are too coarse for a short drive.

Why it helps

Whole percentage points are blunt on a 10-mile drive and can mislead by a mile or more per point.

Verification

Two repeats of the same route should now land within a point or two of each other.

A worked example, with invented numbers

Everything here is hypothetical, to show the arithmetic, and it is not Tesla data. Suppose a 40-mile route used 14, 15 and 17 battery percentage points on three different days.

• Best day: 14 points over 40 miles is 0.35 points per mile.
• Middle day: 15 points over 40 miles is 0.375 points per mile.
• Worst day: 17 points over 40 miles is 0.425 points per mile.

Now suppose the car shows 60 percent. At 0.35 points per mile that is 60 ÷ 0.35 = about 171 miles. At 0.375 it is 60 ÷ 0.375 = 160 miles. At 0.425 it is 60 ÷ 0.425 = about 141 miles. The gap between best and worst is roughly 30 miles from the same battery, on the same route, with the same car. The screen could only ever show you one of those numbers. Planning on 141 miles is the safer decision rule, and it leaves room for the day that turns out worse than any you have measured.

Three rules that follow

1. Trust the percentage for energy, and your own figure for distance. The screen’s distance is a starting point, not a promise.
2. Keep a buffer you chose in advance. Decide before you leave what you will not drop below, and treat reaching it as the end of the plan, not a target.
3. Re-measure when the conditions change. New season, new tires, a roof box, a different commute: your yardstick is out of date.

For trips beyond your usual routes, put the same logic into the trip buffer planner, which turns your consumption figure and a buffer into a distance you can plan around.