The calculator
Every box starts empty, and it stays empty until you fill it. We don't know what fuel costs where you live, what your insurer charges you, or what you paid for your car — so we don't pretend to. Type what you actually pay. A blank box counts as zero, which means the total only ever contains what you told it.
Use whatever units you think in — miles or kilometres, and your own currency. The sum doesn't care which, only that you stay consistent. Figures are shown without a currency symbol for the same reason.
Fill in what you know above and the year’s arithmetic appears here.
Every figure above is one you typed. We didn't supply a single number, and this answer isn't advice — it's your arithmetic, done quickly.
No black box. This is the whole calculation, and you can do it on paper — or with the calculator switched off.
- Trips a year = trips a week × weeks a year
- Distance a year = trips a year × the one-way distance
- Fuel per unit of distance = price of a unit ÷ how far the car goes on one
- Driving those trips = distance a year × (fuel per distance + wear per distance) + trips a year × parking per trip
- The car regardless = payment × 12 + insurance + registration and the rest
- Riding those trips = (bike + kit) ÷ years you spread them over + maintenance + storage + fallback trips × what one costs
- The difference = driving − riding. The car's fixed costs join the driving side only if you said the car could actually go.
Blank counts as zero throughout. Left blank, the years-to-spread figure is treated as one — the whole bike charged to a single year, which is the reading least kind to the bike.
There’s a version of this article all over the internet, and it always ends the same way: a big confident number, a headline about how much the average driver could save, and a quiet footnote about where the figure came from. We’re not going to do that. We don’t know what fuel costs on your corner, what your insurer charges you, how far your commute runs, or whether you’d actually ride it in February. So we’re not going to invent it.
What we can do is hand you the arithmetic and ask you for the numbers. At the foot of this page there’s a calculator with about seventeen empty boxes and not one figure supplied by us. Fill in what you actually pay, and it will tell you what a year of those trips costs by car and what the same year costs by bike. The answer might be that riding saves you real money. It might be that it doesn’t. Both are useful; only one of them is usually printed.
Why we won’t fill in a single number for you
Every figure this calculation needs is either volatile (fuel, insurance, parking, all of which move by the month), regional, or simply personal. A default we typed in would be a number you can’t check, and it would nudge you toward an answer you’d then believe. That’s the exact trade this site refuses to make.
There’s a second reason, and it’s the more practical one: an average is a poor guide to a particular life. The person with a paid-off small car, free parking at work, and a two-mile commute is in a completely different situation from the person financing a truck and paying for a garage downtown. One national figure describes neither of them. Your own figures describe you exactly.
Two piles, not one
The mistake almost every version of this sum makes is to treat “what the car costs” as one number. It isn’t. It’s two, and they behave completely differently.
What a trip costs. Fuel or charge, parking, tolls, and the wear you put on tyres and brakes and the servicing schedule. These are real, and they fall the moment you stop making the trip. Ride to work instead of driving, and this pile shrinks.
What the car costs regardless. The payment or the finance, the insurance, the registration, the tax, the inspection, the permit for the space. These don’t care whether the car moved this week. A bike in the shed does nothing to them. They fall only if the car itself goes.
This distinction is the whole core of the question, and it’s why the calculator holds the second pile out of the headline number unless you tick a box saying the car could really go. Switching your commute to a bike does not reduce your car payment. It’s an easy thing to blur, and blurring it produces a very flattering, very wrong result.
| Falls when you ride instead | Falls only if the car goes | |
|---|---|---|
| The car | Fuel or charge, parking, tolls, wear and servicing spread over the miles | Payment or finance, insurance, registration and tax, a permit or a space |
| What that means | Ride more and this shrinks, trip by trip | Ride every day and this doesn't move at all |
If dropping a car (from two to one, or one to none) is on the table for you, that’s where the large numbers live, and the calculator will fold them in when you say so. But it will also warn you, at that point, that a household without a car has to get to every trip it can’t make by bike some other way, and that has to be paid for too.
The bike is not free either
A comparison that can only ever conclude “ride” is advertising. So the calculator asks about the bike side with the same seriousness:
- The bike itself, if you’d be buying one — spread over however many years you think it’ll last. That’s your call, not ours. Leave the years blank and the whole cost lands on this one year, which is the harshest possible reading for the bike.
- The kit that makes the trip real — a lock you trust, lights for the dark half of the year, mudguards, a rack, something to keep the rain off. This is the part people forget, and it isn’t small.
- Upkeep — tyres, brake pads, chains, the occasional service, and the electricity if it’s an e-bike. Bikes are cheap to run, not free to run. (Our guide to the maintenance that actually matters is the short version of what that buys you.)
- Somewhere to keep it — a locker, a shed, a cage at work. Sometimes zero, sometimes not.
- The days you don’t ride. This is the one that decides a lot of these sums. A downpour, a late meeting, a load too big for the bike — and you take a bus, a rideshare, a car anyway. Multiply those by what one costs, and put the result on the bike’s side of the ledger, where it belongs.
That last line is where a careful calculation usually parts company with a promotional one. Nobody rides every trip. Count the exceptions.
How the sum is done
No black box — here’s the whole thing, and it’s on the page under the calculator too, so it still works with JavaScript switched off:
- Trips a year = trips a week × weeks a year. (Weeks a year, not fifty-two, unless you really mean fifty-two.)
- Distance a year = trips a year × the one-way distance.
- Fuel per unit of distance = what a unit of fuel or charge costs ÷ how far your car goes on one. Works the same whether you buy gallons, litres, or kilowatt-hours.
- Driving those trips = distance a year × (fuel per distance + wear per distance) + trips a year × parking per trip.
- Riding those trips = (bike + kit) ÷ the years you’d spread them over + upkeep + storage + fallback trips × what one costs.
- The difference = driving − riding. The car’s fixed costs join the driving side only if you’ve said the car could actually go.
Use whatever units you think in — miles or kilometres, and your own currency. The arithmetic doesn’t care which, as long as you’re consistent. That’s also why no currency symbol appears anywhere: we don’t know where you are, and we’d rather not guess.
What the number leaves out
It’s a cost calculator. It accounts for money and stays silent about everything else, and the things it’s silent about are not small:
- Your time. A bike trip may be faster or slower than the drive. In dense traffic with parking at the far end, riding often wins outright; on an open highway it rarely does. Neither shows up in the sum.
- Your health. Twenty minutes of movement, twice a day, most days, is worth something. It’s real, it’s well documented, and there is no clean way to price it in a box on a web page — so we don’t try.
- What the trip is like. Some people arrive from a drive tense and from a ride settled. That’s real, even if it isn’t a number.
- Depreciation and resale. Cars lose value over time; so do bikes, more slowly. Both are hard to pin down, and a figure we invented would be exactly the kind of confident nonsense this page exists to avoid. If you know your own, you can fold it into the wear line.
- The car you keep anyway. For most households the realistic outcome is fewer car trips, not no car. That’s a smaller saving than the internet promises — and still a saving.
What to do with the answer
If it comes out in the bike’s favour, you’ve got a number you can trust, because you built it. If it comes out the other way — and for a paid-off car, a short drive, free parking, and a bike you’d have to buy from scratch, it well might — then you’ve learned something more useful than a headline: the case for riding, for you, isn’t the money. It’s the health, the mood, the not-sitting-in-traffic, the arriving somewhere on your own steam. Those are decent reasons. They just aren’t this page’s reasons.
And if it comes out close, that’s the most common result of all, and it means the deciding factors were never financial. Which is good news, in a way: it means you get to choose.
If you’re not sure what bike this hypothetical is even about, start with which bike is right for you. And if you’re weighing whether you’d really ride through the wet months (the assumption most of these calculations get wrong), read the all-weather commuter setup first, then come back and fill in the fallback line for real.
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