Why Cash Paid at Booking Moves the Portal vs Transfer Crossover

The portal-versus-transfer comparison has one number that decides it: the cash fare of the award ticket at which both paths are worth the same dollars. That crossover fare is the portal's value for your points plus whatever cash you still pay at booking. The Portal vs Transfer Calculator prints it, and the cash term is the part casual comparisons leave out.

The formula

The calculator's engine works the crossover out in three lines:

portal value   = bank points × portal rate ÷ 100
transfer value = cash fare − cash paid at booking
crossover fare = cash paid + portal value

Transferring wins when the ticket's cash fare is above the crossover fare, and the portal wins when it is below. The transfer ratio does not appear in these lines. Why your transfer ratio doesn't decide portal vs. transfer covers that. This guide is about the other input, cash paid.

Why cash paid belongs in the comparison

An award ticket is rarely free of cash. The Transportation Security Administration states that "the fee is currently $5.60 per one-way trip in air transportation that originates at an airport in the U.S.", and that "the fee imposed per round trip shall not exceed $11.20" (TSA, security fees). That is the September 11 Security Fee. Because the fee applies to a trip, it is cash due on the booking even when points pay for the seat.

The transfer path only saves you the part of the fare the points cover. So its value is the fare minus the cash you still hand over. The portal path is priced from your points alone. Cash paid therefore raises the bar the fare must clear, dollar for dollar.

A worked example

These inputs are illustrative. The portal rate is an assumption you set yourself, and 1.25¢ is a placeholder here, not a published rate for any card.

• Bank points: 50,000
• Portal rate: 1.25¢ per point (assumed)
• Cash paid at booking: $11.20 (two one-way trips, each at $5.60, which is the round-trip cap TSA states)

portal value   = 50,000 × 1.25 ÷ 100 = $625.00
crossover fare = $11.20 + $625.00    = $636.20

Now test a round-trip award whose cash fare is $630.00:

transfer value = $630.00 − $11.20 = $618.80
portal value   = $625.00
difference     = $618.80 − $625.00 = −$6.20

The portal wins by $6.20. A comparison that skips the cash paid would set the $630.00 fare against the $625.00 portal value, see the fare ahead by $5.00, and call it for transferring. The fare sits above $625.00 but below the $636.20 crossover, so the answer flips in a $11.20 band.

At a $900.00 fare the cash term no longer changes the verdict. Transfer value is $900.00 − $11.20 = $888.80, which is $263.80 above the $625.00 portal value. The cash term matters most when the fare sits close to the portal's value.

What this does not capture

• The $5.60 and $11.20 figures are the US September 11 Security Fee only. Other taxes and carrier surcharges vary by itinerary and are not sourced here. Enter whatever your booking screen shows as cash due.
• The portal rate is an input because it depends on your card and can change. Look up the rate your card gets and enter it.
• The comparison uses one specific fare. It says nothing about whether award space exists on the dates you want, or what the same seats cost on other days.
• It does not value the miles and card rewards you would earn by paying cash. The Award vs Cash Calculator handles that term separately.
• The fee amounts are as stated on the TSA page when this guide was reviewed. Check the current figure before relying on it.

Put your own points, portal rate and booking cash into the Portal vs Transfer Calculator to see the crossover fare for your trip.

This guide is informational only and is not financial or travel advice. Written by Eric, PointCents founder.

Last reviewed: October 2026

Sources

• Transportation Security Administration, security fees (49 CFR § 1510.5)

Frequently asked questions

Does paying cash at booking change which path wins?

Yes. The calculator sets the crossover fare at your cash paid plus the portal's value for your points. Any cash due at booking raises the fare an award must carry before transferring beats the portal.

How much is the cash I pay on a US award ticket?

The TSA states the September 11 Security Fee is $5.60 per one-way trip that originates at a US airport, capped at $11.20 per round trip. Other charges depend on the booking, so enter the cash your booking screen shows.

Do I need to know the transfer ratio to find the crossover fare?

No. The crossover fare is built from the portal value and the cash paid, and neither uses the ratio. The ratio decides how many partner points you end up with, not which path is worth more for the same bank points.

Why does the calculator ask for the portal rate?

The rate depends on the card you hold and is not published somewhere a tool can check. You enter the rate your card gets, and the tool computes from that.