A passenger lands on your site on a Tuesday lunchtime. They need a cab from a postcode in the centre of town to the airport, for 6am on Saturday. Three things happen in their head in the first ten seconds. How much is it. Can I pay now. Is this firm still trading.
A fare calculator answers the first one. Not an emailed quote, not a “call us for a price”, not a contact form with a subject dropdown. A number on the page, under the postcode boxes, inside three seconds. That is the single thing that keeps a price-shopper from bouncing to the app next door.
Most firm owners know they should have one. Fewer know how the thing actually works under the bonnet, and fewer still know why a calculator that disagrees with the driver’s meter is worse than no calculator at all. Here is the short version.
What a Fare Calculator Actually Does
A taxi fare calculator is four jobs stitched together. None of them are clever on their own. The cleverness is in wiring them up so the passenger sees a price in under three seconds.
- Postcode lookup. The passenger types “SW1A 1AA” and “LGW”. The calculator turns those into latitude and longitude pairs. Most of the UK uses the free Postcodes.io API or the paid Ordnance Survey Places API for this. Airport codes are a short lookup table.
- Route and distance. The two coordinate pairs go to a routing engine, usually Google Distance Matrix, Mapbox, or OSRM for the frugal. The engine returns a driving distance in miles and a duration in minutes. It accounts for motorways, one-way streets, and typical traffic for the chosen time.
- Tariff lookup. Your firm’s pricing rules are stored as a table. Base fare, per-mile rate, waiting time, surcharges. The calculator picks the right row based on the day of the week, the time of day, and the vehicle type the passenger chose.
- Fare calculation and display. Base plus (miles times rate) plus surcharges plus any fixed airport fee. Round to the nearest pound if you price that way. Show the number. Offer a “book this quote” button that locks it in.
The passenger never sees the first three steps. They see the boxes, the button, and the number. Everything behind that should be invisible and fast.
Why the Quote Has to Match the Meter
This is the bit that matters, and it is the bit most firms get wrong.
Here is the scenario. A passenger books online. The calculator says £22.50 for a run from the town centre to the airport. The driver turns up, runs the meter the whole way, and at the airport the meter reads £28.80. The passenger argues. The driver calls dispatch. Dispatch shrugs. Someone eats the difference. Probably the driver. Definitely your Google review.
This happens for four reasons, and every one of them is fixable.
- The calculator uses a different distance to the meter. The site used straight-line distance, or Google’s default route, and the driver took a shorter B-road that happens to be two miles longer on the meter’s GPS. Fix: use the same routing engine, or quote fixed fares by postcode pair.
- The tariff on the site is last year’s. You put prices up in October and nobody updated the calculator. Fix: store tariffs in one place (your dispatch system or a shared table) and pull from there, not from a hard-coded number in the theme.
- The calculator does not know about surcharges. Bank holiday, after midnight, more than four passengers, pet on board. The meter adds them. The calculator does not. Fix: model surcharges explicitly and show them as a line item (“Tariff 2 rate applies, £4.20 surcharge included”).
- Waiting time. The driver was held up at pickup for ten minutes. The meter charged it. The calculator did not. Fix: for pre-booked private hire, lock the quote regardless of waiting time up to a reasonable threshold, and tell the passenger that in plain English on the confirmation.
The golden rule: the price the passenger sees on the site is the price they pay at the door. Private hire fares are fixed at booking by law anyway. Treat that as an asset, not a risk. A locked quote is the reason a passenger books you instead of Bolt.
Meter, Quote, or Both
Hackney carriage work and private hire work run on different rules, and the calculator has to know the difference.
- Hackney (black cab) work is metered. Fares are set by the local licensing authority, which in London is TfL. The meter is the legal source of truth. A website calculator for a hackney firm is an estimate, and it should say so clearly. See the TfL hackney fare order for the current London tariffs.
- Private hire (PHV) work is pre-booked only. The fare must be quoted at booking and fixed. A website calculator for a PHV firm is not an estimate, it is the quote. Whatever the page shows, the driver charges. No more, no less.
Most UK firms run both. A good calculator asks the passenger whether they want a metered black cab or a pre-booked private hire car, and it uses the right model for each. The site we are describing is the free taxi fare calculator we built into every Essential and Fleet tier. It handles both, and it is honest about which one a passenger is getting.
The Data You Need Before You Build One
Before a single line of code is written, your calculator needs five things written down in plain English. Most firms have these in their dispatcher’s head, not on paper. Get them on paper.
- Base fare. The flag drop. What the meter shows the second the passenger gets in, or the minimum fare on a PHV booking. Typical UK PHV base fare is £2.50 to £3.50. London hackney Tariff 1 starts at around £3.80.
- Per-mile rate. Most PHV firms charge £1.80 to £2.50 per mile. Some split this by the first two miles and the rest. Write down both rates if you use split pricing.
- Time bands. When does the evening rate kick in. When does the night rate. What happens on Christmas Day. A lot of firms forget they have three tariffs until the dispatcher points it out.
- Surcharges. Waiting time (around £0.40/min is common), extra passengers, large luggage, pet in vehicle, card payment fee if you charge one.
- Fixed quotes. Any postcode pair or airport run where you charge a set fee regardless of the meter. List every one of them. Airport runs are almost always fixed.
If the web designer you are speaking to does not ask for all five of these in the first call, they are about to build you a contact form with a tip jar.
Where Fare Calculators Break
We have rebuilt calculators for firms that had one already and were unhappy with it. The failure modes cluster into four categories.
- Slow. The calculator takes seven seconds to return a price. The passenger has already bounced. Routing and tariff lookup should complete in under a second on a 4G phone. If your host is slow, move to a proper managed stack. If your routing API is paid per call, cache common routes.
- Broken on mobile. The postcode field does not show a numeric keyboard. The submit button is hidden under the soft keyboard. The result renders off-screen. Roughly 80 percent of taxi traffic is on a phone. A broken mobile calculator is a broken calculator.
- Quote does not pass to booking. The passenger sees £22.50, clicks “book this”, fills in a form, and the dispatcher sees a fresh booking with no fare attached. The quote was never saved. Fix: store the quote id and reference it in the booking record that lands in iCabbi, Autocab, or Cordic.
- No dispatch handover. The booking lands in an email inbox. The dispatcher re-keys it by hand. Something gets mistyped. The driver goes to the wrong end of the road. Fix: push the booking straight to your dispatch platform’s API with the quote, the addresses, the pickup time, and the vehicle type.
If you want to see what a working one looks like on the conversion side, we covered the three-tap booking funnel in detail at three taps to booked.
Why It Earns Its Keep
A fare calculator is not a luxury feature. It is the single thing that stops a price-shopper leaving your site and booking with the app next door. On the six firms we have built this for, the numbers land in the same place every time.
- Sessions that use the calculator convert to booking at 15 to 22 percent. Sessions that do not sit under 3 percent.
- Average booking value on quoted jobs is about 4 percent higher than unquoted jobs. Passengers who see the price accept it. Passengers who phone to ask haggle.
- Dispatch re-keying time drops from about 90 seconds per web booking to zero. On a firm doing 40 web bookings a day, that is an hour of dispatcher time back, every day.
None of this is magic. It is a postcode box, a routing call, a tariff table, and a working handover to your dispatch platform. Done right, it pays for the whole site in the first quarter.
What It Costs to Add One
Our Essential tier includes a fare calculator and dispatch handover in the £799 one-off build. The Fleet tier at £1,499 adds multi-vehicle pricing, airport fixed quotes per terminal, and an account portal for corporate clients. Full breakdown on the pricing page, and the full scope of each build sits on the services page.
If you already have a site and just need the calculator rebuilt, we do that as a standalone piece of work too. The shape of the quote depends on whether your tariffs are clean, whether dispatch has a public API, and how many fixed-fare postcode pairs you want baked in.
Your Move This Week
You do not need to commission a new calculator this week. You need to know whether the one you have is lining up with the meter. Three steps, about 20 minutes.
- Pick three real jobs from yesterday’s run sheet. A short local hop, an airport run, and a long out-of-town job. Write down what the driver charged.
- Quote each one on your own website. Use the same postcodes. Check what your calculator returns. Compare to what the driver actually charged.
- If any of the three is more than 10 percent off, request an audit. We will look at your calculator, your tariff setup, and your dispatch handover, and send you a one-page PDF with the fixes. No pitch attached. Request your audit here.
If your current site does not have a calculator at all, the piece to read next is taxi website design, which covers the whole booking funnel including where the calculator sits. And if you want to try a working one right now, ours is live at taxi fare calculator.
A fare calculator is not a gadget. It is a price tag. Put the right one on the site and the phone stops being the only way a passenger can find out what a cab costs.