HMRC Mileage Calculator Guide 2026: Split Rates Without Mistakes

Every employee and self-employed worker who drives for business in the UK needs to understand one calculation: the Approved Mileage Allowance Payment, or AMAP. Get it right and you claim the full relief you are entitled to. Get it wrong and you either leave money on the table or face an HMRC enquiry.

This guide walks through the AMAP formula, three worked examples, rates for motorcycles and bicycles, and the decision between AMAP and actual costs.

The AMAP formula

HMRC sets two rate bands for cars and vans, published on the GOV.UK approved mileage rates page:

• First 10,000 business miles in the tax year: 45p per mile
• Every mile above 10,000: 25p per mile

The formula looks like this:

Total claim = (first 10,000 miles × 45p) + (remaining miles × 25p)

The threshold resets on 6 April each year. Miles from different tax years cannot be combined.

Three worked examples

Example 1 — Sales rep, 8,000 business miles

Sarah is an employed sales representative. She drives her own car to visit clients and logs 8,000 business miles in the 2025-26 tax year.

All 8,000 miles fall within the first band:

8,000 × £0.45 = £3,600

Her employer does not reimburse mileage. Sarah can claim the full £3,600 as Mileage Allowance Relief (MAR) on her Self Assessment return or by writing to HMRC.

Example 2 — Consultant, 14,000 business miles

James is a self-employed IT consultant. He drives 14,000 business miles during the tax year.

The first 10,000 miles are at the higher rate and the remaining 4,000 at the lower rate:

(10,000 × £0.45) + (4,000 × £0.25) = £4,500 + £1,000 = £5,500

James enters £5,500 on his Self Assessment tax return as a business expense.

Example 3 — Employee with partial reimbursement (MAR claim)

Lucy drives 12,000 business miles and her employer reimburses her at 30p per mile. Because 30p is below the AMAP rate, Lucy can claim the shortfall as Mileage Allowance Relief.

First, calculate what HMRC allows:

(10,000 × £0.45) + (2,000 × £0.25) = £4,500 + £500 = £5,000

Then subtract what her employer already paid:

12,000 × £0.30 = £3,600

Lucy’s MAR claim:

£5,000 − £3,600 = £1,400

She claims this through form P87 or her Self Assessment return. HMRC explains the process on the claim tax relief for your job expenses page.

Motorcycle and bicycle rates

AMAP is not limited to cars and vans. HMRC publishes flat rates for two other vehicle types:

• Motorcycles: 24p per mile (flat rate, no threshold split)
• Bicycles: 20p per mile (flat rate, no threshold split)

These rates apply to the full distance regardless of how many miles you cover. There is no higher or lower band — the rate stays constant no matter how far you ride in the tax year.

Motorcycle example

A motorcycle dispatch rider covering 9,000 business miles in the tax year can claim:

9,000 × £0.24 = £2,160

If the same rider covered 15,000 miles, the rate would still be 24p throughout — no threshold split applies. The claim would be 15,000 × £0.24 = £3,600.

Bicycle example

A courier who cycles 3,000 business miles can claim:

3,000 × £0.20 = £600

The bicycle rate is modest, but for regular cycling couriers or employees who cycle between sites, it adds up. Pedal-assist e-bikes qualify for the same 20p rate — HMRC does not distinguish between standard bicycles and electric bicycles for AMAP purposes.

Passenger payments

There is one additional AMAP element that people overlook: if you carry a passenger who is also travelling for business, you can claim an extra 5p per mile for each qualifying passenger. This applies to cars and vans only, not motorcycles or bicycles. For example, two colleagues sharing a car for a 200-mile business round trip means the driver claims an extra 200 × £0.05 = £10 on top of the standard AMAP rate.

What to calculate each month

Waiting until January to total everything up invites mistakes. A better approach is to reconcile monthly:

• Verified business miles for the month
• Cumulative annual business miles (running total since 6 April)
• Amount still within the first 10,000-mile band
• Amount that has crossed into the 25p band

This monthly discipline means you always know where you stand against the threshold. If you cross 10,000 miles in November, every mile from that point onward is at 25p — and your records should reflect that immediately, not as a surprise in March.

Where calculation errors happen

Mixing personal and business miles

The most common mistake is feeding raw GPS data into a calculator without filtering out personal and commuting journeys first. Only genuine business miles qualify for AMAP. Ordinary commuting — your regular home-to-office trip — does not count.

Ignoring the cumulative threshold

Some people apply 45p to every journey all year. That works fine until you pass 10,000 miles. If you do not track the running total, you will overclaim and need to correct later.

No reconciliation trail

If your calculator output is not tied to monthly source records, you cannot defend the numbers during an HMRC check. Keep the monthly summaries alongside your journey logs.

Applying the wrong rate to the wrong vehicle

AMAP rates for cars and vans (45p/25p) are not the same as motorcycle rates (24p flat) or bicycle rates (20p flat). If you switch between vehicles during the year, each vehicle type needs its own running total. Mixing them in a single calculation produces an incorrect claim.

Forgetting passenger payments

If you carry a colleague who is also travelling on business, you can claim an additional 5p per mile for each qualifying passenger. This is easy to overlook because it requires noting who was in the car, not just where you drove.

Suggested calculator output format

For each month, store:

Month	Business miles	Cumulative	Rate band split	Calculated amount	Source file
Apr	1,200	1,200	1,200 × 45p	£540.00	apr-export.csv
May	1,400	2,600	1,400 × 45p	£630.00	may-export.csv
…	…	…	…	…	…
Dec	1,100	10,800	200 × 45p + 900 × 25p	£315.00	dec-export.csv

A simple table is enough if maintained consistently. The point is traceability — every number ties back to a source export.

When to use actual costs instead of AMAP

AMAP is simple, but it is not always the best choice. You can instead claim actual motoring costs: fuel, insurance, servicing, road tax, MOT, breakdown cover, and a capital allowance on the purchase price.

You must then split total costs between business and personal use based on the proportion of business miles.

The AMAP vs actual costs decision

Choose AMAP when:

• You drive a fuel-efficient or lower-cost vehicle
• Your annual business mileage is moderate (under ~15,000 miles)
• You prefer simplicity and minimal paperwork
• You do not want to keep fuel receipts and service invoices

Choose actual costs when:

• You drive a high-mileage, expensive vehicle with significant running costs
• Your fuel, insurance, and depreciation costs exceed what AMAP would give you
• You are willing to keep detailed receipts for every motoring expense
• You are self-employed (employees cannot use actual costs for their own vehicle — AMAP is the only option for employees using personal cars)

One critical rule: if you are self-employed and choose actual costs for a vehicle, you cannot switch to AMAP for that same vehicle later. The choice is locked in for the life of the vehicle in your business. HMRC guidance on this is in the simplified expenses section of GOV.UK.

For most people driving a standard car for moderate business mileage, AMAP produces a fair result with far less admin.

Worked comparison

Suppose you are self-employed and drive a mid-range petrol car 12,000 business miles in the tax year. Your actual annual motoring costs (business proportion only) are:

• Fuel: £1,800
• Insurance: £450
• Servicing and MOT: £350
• Road tax: £180
• Capital allowance (18% writing-down on £15,000): £2,700 in year one, declining thereafter

Year-one actual costs total roughly £5,480. The AMAP claim for 12,000 miles is (10,000 × 45p) + (2,000 × 25p) = £5,000. In year one, actual costs edge ahead — but from year two onward, the capital allowance shrinks and AMAP likely wins. Factor in the extra bookkeeping burden of tracking every receipt, and AMAP is the simpler long-term choice for most drivers.

How self-employed and employed drivers differ

The AMAP formula is the same for everyone, but how you claim depends on your employment status.

Self-employed drivers enter their mileage claim on their Self Assessment tax return (SA103 for sole traders). They deduct the AMAP amount from trading profits. They can alternatively choose actual costs, but the choice is permanent per vehicle.

Employed drivers who use their own car for business have two routes:

1. If your employer reimburses at or above the AMAP rate, there is nothing further to claim.
2. If your employer reimburses below the AMAP rate (or nothing at all), you claim Mileage Allowance Relief. For claims under £2,500, use form P87. For claims above £2,500, you need to file a Self Assessment return.

Employed drivers cannot choose actual costs for their own vehicle. AMAP is the only option.

Monthly close checklist

Before recording your monthly totals:

1. Confirm the period matches the tax year (6 April to 5 April)
2. Confirm only business miles are included — no commuting, no personal trips
3. Confirm the threshold split is correct based on cumulative miles
4. Confirm source journey exports are archived alongside the calculation
5. Check for any employer reimbursements that need subtracting

Related UK guides

• HMRC Mileage Rates 2026: Practical AMAP Guide for UK Claims
• HMRC Mileage Log Template: Simple Format for Claim-Ready Records
• Mileage Claim HMRC: Self-Employed Workflow That Survives Review

MileTrack captures journeys automatically, classifies them as business, commute, or private, and exports claim-ready reports with all the fields HMRC expects. See the current UK product page at miletrack.app/en-gb.

Tax note: educational content only, not tax advice.