EV Charge Stops Planner

A simple offline tool to estimate how many charging stops you'll need for a long trip.

What this calculator does

Estimate how many charging stops you need on a trip based on distance, vehicle range, starting state of charge, and a minimum battery buffer. The planner also suggests a first leg distance and a typical distance between subsequent stops to help you space chargers.

Inputs explained

Trip distance: Total miles or kilometers to your destination.
Vehicle range: Expected real world range on a full charge.
Start state of charge: Battery percent at departure.
Minimum state of charge: Buffer percent you want to keep on arrival at a stop.
Distance unit: Miles or kilometers for all outputs.

How it works / Method

Compute the first leg range using your start percent down to the minimum percent.
Compute the next leg range assuming you charge back to 100% between stops.
Subtract the first leg from total distance, then count how many next legs are needed.
List the segment distances so you can place charging stops.

Formula(s) used

first_leg = range * (start% - min%)/100

next_leg = range * (100 - min%)/100

remaining = distance - first_leg

stops = ceil(max(0, remaining) / next_leg)

Units: distance in mi or km. Assumes a full charge between stops for the next leg distance.

Trip Details

Total Trip Distance

Vehicle Usable Range (100%)

Enter your conservative highway range.

Start SOC

Min Arrival SOC

Buffer for safety.

Strategy

Total Stops Required -

First Leg Distance -

Subsequent Leg Max -

Trip Segments:

Enter details to see plan.

Step-by-step example

Example inputs: 420 miles trip distance, 250 miles range, start 90%, minimum 10%.

First leg: 250 * (90 - 10) / 100 = 200 miles.
Next leg: 250 * (100 - 10) / 100 = 225 miles.
Remaining distance: 420 - 200 = 220 miles.
Stops needed: 220 / 225 = 0.98, so 1 stop.
Plan: Drive 200 miles, charge, then drive 220 miles to destination.

Use cases

Estimate the number of charging stops on a road trip.
Plan maximum spacing between chargers on a route.
Compare routes by adjusting range or buffer settings.
Decide if you need a longer initial charge before departure.
Check how a larger buffer affects stop count.
Use as a fast check before a detailed charger search.

Assumptions & limitations

Assumes you can charge back to 100% before each subsequent leg.
Does not model charging time, pricing, or charger availability.
Range is treated as constant and does not vary by speed or terrain.
Does not account for elevation, wind, or weather changes mid-trip.
Minimum SOC is a user preference and may differ from vehicle warnings.
Results are estimates for planning, not a guarantee.

Disclaimer: Results are estimates for planning only. Real world stop counts can vary by conditions, speed, and charging availability.

Frequently Asked Questions

Why does the planner assume full charges between stops?

The planner uses a simple model so you can quickly estimate stop counts. It assumes that after the first leg you can charge back to 100% and then drive down to your minimum buffer. Real trips often use shorter charge sessions, especially on DC fast chargers where charging slows near the top of the battery. If you plan to stop around 80%, reduce the range input or increase the minimum buffer to keep the distances realistic.

Should I use rated range or real world range?

Use your real world range whenever possible. Rated range is measured in standardized tests and can be optimistic for highway speeds, cold weather, or heavy loads. If you only have a rated value, apply a conservative adjustment based on your recent driving. Using a realistic range helps prevent underestimating the number of stops you need.

What if I only plan to charge to 80%?

Charging to 80% is common on road trips to save time. In that case, lower the range input to represent the distance you can drive from 80% down to your minimum buffer. Another option is to increase the minimum buffer so the usable window shrinks. Either method will shorten the next leg distance and increase stop count if needed.

How does the minimum SOC affect the result?

The minimum SOC is your safety buffer at the end of each leg. A higher minimum SOC means you are willing to use less of the battery, which shortens each leg and increases the number of stops. A lower minimum SOC increases leg length but leaves less margin for detours or weather. Choose a value that balances comfort and efficiency for your route.

Does this include charging time or station availability?

No. This tool only estimates the number and length of driving legs. It does not include charging time, station power, pricing, or how busy a location might be. Use the charging time calculator or a live charger locator to estimate how long a stop might take and whether stations are available along your route.

Can I use kilometers instead of miles?

Yes. The distance unit selector applies to all inputs and outputs, so you can plan trips in kilometers or miles. Just keep the range and distance in the same unit, and the calculator will keep the segments consistent. The stop count will be the same regardless of units.

Sources & references

DOE Alternative Fuels Data Center: EV charging options for consumers - Charging level overview and typical power ranges.
U.S. DOE Energy Saver: Fuel economy in cold weather - Notes temperature effects on energy use and range.
U.S. Energy Information Administration: Measuring electricity - Defines kW and kWh units used in EV planning.
Schema.org: FAQPage, WebPage, and BreadcrumbList - Structured data definitions used on this page.