# Why stopping at 80 percent at a fast charger is often smart > The last 20 percent at a fast charger costs a lot of time, and sometimes money. A worked example shows when stopping pays off and when to keep charging. Published: 2026-03-17 · Language: en · Source: https://laadpaalvinden.be/en/blog/why-charge-to-80-percent/ At a fast charger, charging to 100 percent feels logical: you are there anyway. Yet on a long trip, many EV drivers stop at around 80 percent. There is simple arithmetic behind it. ## Why the last percentages are slow A fast charger does not deliver the same power for the whole session. As your battery fills up, the car itself asks for less current. You can read how that works in our piece on the [charging curve](/en/blog/charging-curve-fast-charging-slows/). The result: the first 80 percent goes much faster than the last 20. ## A worked example Take a car with a usable battery of 60 kWh and a consumption of 18 kWh per 100 km. We assume the charger delivers an average of 100 kW up to 80 percent and an average of 40 kW after that. Real figures depend on your car, the charger and the temperature, but the proportions hold roughly. - From 10 to 80 percent you add 42 kWh. At 100 kW that takes about 25 minutes and is good for around 233 km. - From 80 to 100 percent you add 12 kWh. At 40 kW that takes 18 minutes and is good for around 67 km. So for those last 67 km you stand at the charger almost as long as for the first 233. Per kWh, the last step takes 1.5 minutes and the first 0.6 minutes. In time, you pay 2.5 times as much for the same amount of energy. ## What it costs If the charger bills per kWh, the price per kWh stays the same however slowly it goes. You mainly lose time. If it bills per minute, or adds a per-minute fee on top, the last 20 percent really does get more expensive: for the same energy you pay 2.5 times as many minutes. Check the tariff in the app or on the charger before you start, because it differs per operator and changes over time. More ways to bring the bill down are in our piece on [cutting fast charging costs](/en/blog/cut-fast-charging-costs/). ## Someone may be waiting At busy fast-charging sites, especially on holiday weekends, a queue sometimes forms. Every minute you stay longer than you need to, someone else waits. Driving on as soon as you have enough range is part of [charging etiquette](/en/blog/ev-charging-etiquette/). Some operators also charge an extra fee if you stay after charging has stopped. You can read how to avoid that under [idle fees](/en/blog/avoid-idle-fees-charging/). ## How to decide where to stop 1. Check how many kilometres you still have to drive to the next charging stop or your destination. 2. Add a margin, especially in cold weather, at motorway speeds or on a hilly route. Your consumption will be higher than on everyday drives. 3. Compare the result with the range your car shows. Plenty to spare? Then unplug. 4. Is it tight? Then keep charging, even if that means 100 percent. Work in kilometres. A [route planner app](/en/blog/best-ev-route-planner-apps/) suggests how far to charge at each stop. ## Common mistakes - Charging to 100 percent out of habit, even when you arrive within 50 km at a place where you can charge. - Not checking the charger's power. A 50 kW charger never reaches the average in our example, so every step takes longer. - Forgetting a second short stop as an option. Charging twice to 70 or 80 percent can be faster than once to 100. - Leaving too little margin and driving to the next charger on a nearly empty battery. If that charger turns out to be broken or occupied, you have no alternative. ## When 80 percent does not apply By all means keep charging if the next fast charger is far away or uncertain, for example in a sparsely populated area. The same goes for a mountain drive, in winter or with a trailer: your consumption goes up and you really need those extra kilometres. If you will not be able to charge after you arrive, a full battery at departure is also a good choice. At a normal charger or at home this matters much less. You charge calmly and the last percentages cost no waiting time that counts. How far to charge at home for the sake of the battery itself depends on your car. Check the manual for what the manufacturer recommends. You can read more about the battery in our piece on [battery health tips](/en/blog/ev-battery-health-tips/). Looking for a fast charger on your route? Have a look at the page with [fast chargers](/en/fast-chargers/) or the [map](/en/map/).