£70,403 on paper.
£56,757 in reality.
That's a four-year total cost of ownership comparison between a BMW X3 and its electric counterpart, the BMW iX3 — same driver, same 20,000 miles/year, same 48-month lease, same 40% higher-rate taxpayer. £13,646 difference, over four years, when you account for the tax treatment that governs how UK company cars actually get paid for. The EV transition isn't a question of "when." It's a question of "which vehicles, in what order, and what's it actually going to cost?" Orbis measures the inputs. Covase answers the question.
The EV transition is a measurement problem first.
Every EV transition decision made on published figures is a decision made on fiction. WLTP is a laboratory number. Manufacturer-quoted MPG is a best-case estimate. Driver-reported mileage is a rounded memory. Orbis reads what the vehicle is actually doing — odometer, fuel consumption, trip patterns, idle time — directly from the manufacturer's own API. That's the starting point for any honest EV decision.
From the odometer. Not the driver.
Every trip, every mile, every journey — read directly from the vehicle's own odometer and cross-checked against trip-end telemetry. The number that drives every TCO calculation is the actual measured one, not the one the driver estimated at renewal.
From the vehicle's fuel system.
Not fuel card receipts. Not WLTP. The vehicle tells us what it's burning — through OEM-native APIs, trip by trip. Real MPG, real range, real energy use. The same data underneath our public Tiguan case study showing a 287mpg-on-paper vehicle returning 46.9mpg in reality.
Can this driver even use an EV?
Daily distance, typical trip length, time between journeys, hours parked. These determine whether a 350-mile range is necessary or overkill, whether home charging is feasible, whether this specific driver's day fits an EV at all. Orbis answers that per vehicle, not per fleet.
When can you actually act?
Orbis is connected to the leasing book. Every vehicle has a live remaining contract term and a renewal date. An EV transition plan that ignores when each vehicle actually comes off contract is a plan that can't be executed. Ours doesn't.
Four years. Twenty thousand miles a year. £13,646.
Below: the full UK 2025/26 tax treatment, line by line, for a real pair of vehicles from the Orbis catalogue. 48 months — the UK fleet norm; longer terms available on request. 20,000 miles per year. 40% higher-rate taxpayer. No rounding, no "typical saving" — the actual numbers our calculator produces when you press go.
This isn't a story about EVs being cheaper to run.
The electric BMW leases for more. It costs more to insure. It pays higher VED. From 2028, it'll pay 3p per mile in electric-vehicle excise. On pure operating cost, before any tax consideration, the diesel wins by about £18,000 across four years.
What flips the comparison — and flips it by over £31,000 — is the UK tax treatment of company cars. BIK at 3% climbing to 9% over the next four years, against 36% climbing to 39% for the equivalent diesel. The tax structure is doing exactly what it was designed to do: make fleet electrification the lower-cost choice for the people and the companies making the decision.
Which means "should my fleet switch to EV?" isn't really a question about cars. It's a question about how precisely you can model UK tax policy, how accurately you can measure each driver's real mileage and tax band, and how well you understand when each specific vehicle comes off contract. Get any of those wrong and the comparison flips.
Orbis tracks the rates. Covase runs the transitions. Between them, "should we switch?" becomes a question with an answer.
Orbis measures. Covase makes the call.
Orbis IO is built by Covase — a UK fleet management specialist running company-car fleets for SMEs and large corporates since 2003. Covase are BVRLA members (#2181), FCA-regulated credit brokers, and have been on the inside of the fleet industry for two decades. Their founders started the company because they thought the rest of the sector wasn't being honest enough with its clients. Two decades later, they still work on that assumption.
Not just a calculator.
Covase's whole-life-cost model is the methodology underneath the calculator you just saw. In 2023 Covase published the finding that lease rental accounts for less than 60% of a vehicle's true running cost — fleets making choices based on lease price alone are typically missing £3,000–£10,000 of downstream cost per vehicle per year. Full TCO analysis changes which vehicles belong in which band on your car list — and often opens up EVs at lower grades than expected.
A human, not a form.
Every Covase client has a dedicated account manager — a real person who knows your fleet, your drivers and your renewal calendar. Not a shared inbox. Not a ticketing system. The kind of fleet manager most SMEs can't justify hiring full-time, sitting alongside your finance team and working like part of it.
EV + charger + solar, deducted gross.
Covase's Perx scheme puts the EV, the home charger, the solar panels and battery storage into a single salary sacrifice bundle — deducted gross from pay before tax and National Insurance. Basic-rate taxpayers save around 32% on the package; higher-rate taxpayers save around 42%. It's the piece that turns the TCO case on this page into something your drivers actually feel.
"Unpopular opinion: software doesn't run fleets."
Orbis doesn't disagree. Orbis is the measurement layer — the part fleet operators have always had to build themselves. Covase does the running, like it has since 2003.
Tell us about your fleet.
15-minute call. No sales sequence. No marketing automation. Just a conversation with someone who's run fleets for longer than most fleet software has existed — and who's built the measurement tools we wish we'd had for the last twenty years.