BA Part Pay or a discount code on the same fare: how the Avios earning base changes the maths

BA uses a different earning base for each route. With Part Pay, you earn on the full ticket price before the Avios discount. With a discount or voucher code, you earn on the price after the discount. Part Pay costs Avios and a code does not, so on an equal cash saving the code wins comfortably. The earning rule only matters when the code saves less cash than Part Pay. Even then, it adds roughly your earning rate × the code’s discount, valued at your floor, to the code’s cost. That is 90p in our example below.

What BA’s flight-earning page says

BA’s Collecting Avios on flights page sets out both rules side by side under British Airways flights:

“If you use Avios to part pay the price of a cash ticket, you’ll collect Avios based on the full ticket price before the discount was applied. If you use a discount or voucher code on your booking, the Avios you collect is based on the price after the discount is applied.”

The rule matters because BA’s tier points page says that for British Airways, American Airlines and Iberia, the Avios you collect depend on the amount you spend, not the distance you fly.

What goes into the earning base

On BA-marketed flights, you earn on the ticket price plus eligible add-ons bought as part of the trip, such as extra baggage. Non-airline taxes and fees, such as airport charges and government taxes, earn nothing (BA).

Not every booking fits the price-based comparison below. On the same page, BA says that tickets where the fare paid isn’t available earn on a percentage of miles flown and cabin instead. This includes flights in a British Airways Holidays package and some travel-agent bookings. Reward Flights, agency discounted fares and industry discounted fares earn no Avios at all. Those agency and industry fares are not the same thing as a ba.com discount code.

One formula for both routes

Total cost = cash paid + (Avios spent × your floor) − (Avios earned × your floor)

Your floor is the lowest value you would accept per Avios. It is a personal figure, not a BA one. The earning rule only affects the last term.

Two hypothetical side-by-sides on the same £600 fare

All figures are illustrative, not live prices. The fare is £600, including £150 of non-airline taxes, which leaves a £450 earning base that we assume fully earns. The earning rate of 6 Avios per £ is used purely for the arithmetic, so substitute your own. We also assume a code comes off the fare rather than the taxes, which BA’s page does not specify. The floor is 0.5p per Avios.

Route	Cash paid	Avios spent	Earning base	Avios earned	Total at 0.5p
Code, £60 off	£540	0	£390	2,340	£528.30
Part Pay, £60 off for 6,000 Avios	£540	6,000	£450	2,700	£556.50
Code, £30 off	£570	0	£420	2,520	£557.40

Same £60 saving either way

The cash is identical. Part Pay earns 360 more Avios but spends 6,000 to get them. At 0.5p, the code is £28.20 cheaper. Because the cash is the same, it stays cheaper at any positive value you put on an Avios.

A £30 code against £60 of Part Pay

Only here does the earning rule have any effect. The code costs £30 more in cash but keeps your 6,000 Avios, and it earns 180 fewer Avios than Part Pay. At 0.5p, Part Pay comes out ahead by just 90p.

To find the tipping point, divide the extra cash by the net Avios gap (+2,520 for the code against −3,300 for Part Pay): £30 ÷ 5,820 Avios, or about 0.52p. Below that floor, Part Pay wins. Above it, the code does. If the code earned on the full fare, the break-even would be exactly 0.5p. The earning rule therefore moves the break-even from 0.50p to about 0.52p. In cost terms, it adds 6 × £30 = 180 Avios to the code’s side, worth £0.90 at 0.5p. A larger code or a higher earning rate scales it up.

Our take: if both save the same cash, use the code. If Part Pay saves more cash, choose it only when that extra cash is more than your floor value of the Avios it spends minus the extra Avios it earns. Here that means comparing £30 with 6,000 − 180 = 5,820 Avios.

Check these on your own booking

• Can you combine them? Nothing we retrieved says whether a code and Part Pay can be used on one booking, or which earning base would then apply. We have treated them as alternatives. Check the payment screen.
• What does the code reduce? If it comes off taxes rather than the fare, it may not reduce your earning at all. Compare the price breakdown before and after applying it.
• Your actual earning rate. Replace our illustrative 6 per £ with the rate for your tier and fare.
• Is the booking price-based? For BA Holidays packages and some agent bookings, BA points you to its flight calculator, because those earn on distance.
• Tier points. We found no BA source on how Part Pay or codes affect tier points, so don’t assume they follow the Avios rule.
• Paying in another currency? BA converts the spend to GBP at the IATA 5-day rate on the purchase date before calculating Avios.

If your dates could move after part paying, read our guide to what BA says happens to the money portion.