The price you see is the price you pay: how Volta's total cost preview actually works

The problem with guessing at the pump

EV charging costs are genuinely complicated. There's the per-kWh rate, sure. But there's also parking fees (which can be £2 to £6 an hour in city centres), idle fees that kick in after you've finished charging, and taxes that vary by network and region. Most drivers see one or two of these numbers scattered across different screens, different apps, different networks.

We spent weeks in late 2023 talking to commuters, delivery drivers, and fleet managers. A delivery driver in Manchester told us he'd switched chargers three times in one trip because the first app showed him a 45p per-kWh rate, but didn't mention the £3.50 idle fee. He didn't find out until he was already plugged in. Fleet managers had it worse. They'd get invoices weeks later and couldn't tell drivers why one site cost double another, even though they charged at similar speeds.

The real cost isn't what the network publishes on their homepage. It's what you actually pay. So we decided the app should show that from the moment you search.

What 'true total cost' actually means in the app

When you open Volta and look at a charger on the map, you're seeing four things stacked into one figure: the per-kWh charging rate, any parking charge, any idle fee, and the applicable tax. That's it. That's the number.

It's not a guess. We pull live tariffs from each of the 40+ networks we integrate with. We recalculate it every time you refresh. If Instavolts changes their rate at 9 a.m., you see the new figure at 9:01.

The tricky part was deciding how to present it honestly when the total cost also depends on how long you'll actually charge for. We can't know that. You might need 10 minutes or 40 minutes. So the app shows you the total cost per session, broken down by component. You can see the idle fee threshold (usually 45 minutes, but varies by operator), and you get a sense of whether it's worth waiting for that last 10% of battery at this particular site.

That's the difference between seeing "48p per kWh" and seeing "likely £7.20 total, including 90p parking and a 45-minute idle-free window." One is a number. The other is a decision.

Why we don't hide fees in the small print

I'll be honest: we could make the app simpler by showing just the per-kWh rate, like most other apps do. Cleaner interface. Fewer numbers. But that would be the same mistake everyone else makes.

The moment you decide to build something that genuinely helps drivers, you have to accept that some screens will have more information, not less. Yes, the detail matters. Yes, it makes the UI busier. But a driver who sees idle fees upfront won't rage-book a two-hour charger when a rapid charge will be done in twenty minutes.

We iterate on how to display these details every few weeks. Is the idle fee clear enough? Should we highlight it if it's particularly high for that location? Should we show an estimate of what you'll pay if you charge to 80% versus 100%? Right now, that estimate lives in your journey plan. If you're planning a longer trip, the route planner shows you the charging stops and the likely total cost for each. That helps you pick between a quick expensive rapid and a slower, cheaper destination charger.

A real example: why this matters at a services station

Let's say you're driving up the M25 on a Saturday and your battery hits 20%. You open Volta. You see a BP Pulse charger at the services ahead. Another app might show you "50p per kWh." Volta shows you that same charger, but adds the 50 pence per minute idle fee that kicks in after thirty minutes, plus the £4.50 parking charge for the car park.

If you need 30 minutes to get to 80%, your real cost is roughly £15 for electricity, £4.50 for parking, and zero idle fees. If you linger for forty-five minutes, you're paying an extra £7.50 in idle fees on top. That's the information that changes behaviour. That's the information that makes the difference between "I'll stay and grab a coffee" and "I'll charge and go."

What used to require checking three different sources, or a phone call to the operator, or a nasty surprise when the payment went through, now lives in one place. That's not flashy. It's not a feature that makes headlines. But it's the kind of thing that drivers tell us they actually use every single day.

Building trust by showing what other apps hide

We made a choice early on: we'd rather show too much information than too little. If a charger has an unusual idle fee structure, we make sure it's visible. If parking is included in some networks but not others at the same location, we say so. If a network's pricing changes seasonally, we're transparent about when that happens.

That's partly a business decision. A driver who trusts the app will use it more. But it's also just the right thing to do. You're about to plug in a two-tonne piece of technology worth twenty grand. You deserve to know what it's going to cost before you arrive.

The community charger marketplace works the same way. If you're a homeowner thinking about putting your charger on the platform, you set the rate and the idle window, and that information is displayed in exactly the same format. Drivers see the true total cost for your charger just as they would at a commercial site. No hidden fees. No surprises.