%, mi/$, pts/$: how to read every portal's earning unit

A cashback site pays you a percent, an airline portal pays you miles per dollar, and a points portal pays you points per dollar. Every so often you'll also see a flat "$10 back" or "500 bonus miles" that doesn't scale with what you spend at all. Those aren't the same kind of number, and treating them as if they were is how you end up shopping through the wrong portal for what you're actually buying.

Every portal is really telling you two things: which currency it pays out in (cashback dollars, airline miles, or program points) and how much of that currency you earn per dollar spent. This post is about reading that second part correctly, so a straightforward comparison doesn't turn into a bad one.

The four units you'll see: cashback percent, mi/$ and pts/$

• Percent (%). Cashback portals. "6%" means six cents back for every dollar spent - it's already a share of what you paid, which makes it the easy one to read.
• Miles per dollar (mi/$). Airline portals. "3 mi/$" means three airline miles for every dollar. Whether that beats 6% cash depends entirely on what a mile is worth to you.
• Points per dollar (pts/$). Points portals (MyPoints, Swagbucks, and similar). Same idea, different currency. A few airline-branded portals pay in points rather than miles, too - Southwest and Alaska both do, a naming choice each program makes for itself rather than a data error (see do airline shopping portals share the same platform).
• Flat amounts ($, a fixed number of miles, or a fixed number of points). A one-time bonus like "$10 back" or "500 miles" that pays once and doesn't scale with your spend.

Why we never mash them into one number

We never convert miles or points into dollars behind your back and call it a fact. A mile can be worth very different amounts to different people, depending on how they redeem it. If a tool tells you "3 mi/$ = 3.6% cash," that's someone's assumption, presented to you as if it were true.

So we show every rate in its own native unit, next to the program that pays it, and we compare like with like: cashback against cashback, miles against miles, points against points.

Right now LEGO pays 7% at RetailMeNot, 1 mi/$ at American AAdvantage eShopping, and 3.4 pts/$ at Rove Miles. None of those three numbers is "better" than the others in the abstract - they're not even the same kind of number, so ranking them against each other is like comparing inches to kilograms.

Notice the table groups by currency instead of listing every portal in one pile. That's deliberate, and it goes deeper than portal-versus-portal: the same portal can price different categories of the same store in different units. On Booking.com, BeFrugal pays most categories in percent, but prices flights as a flat dollar amount instead. The unit lives per category, not per store, so read each row for what it actually says rather than assume the whole page uses one unit.

If you do want a single number to compare across currencies, that's a reasonable thing to want. Just do it with your own numbers instead of ours. Turn on Rank by value on a store's page to see the ranking. To use your own numbers, sign in and set your own cents-per-point value (cpp) for each program. We pre-populate a default so the view isn't blank the first time, but everyone values a point differently, and the ranking runs on your values, with our defaults only standing in until you set yours.

Inside one unit, though, ranking is exactly the point. Here's every points-per-dollar portal paying LEGO right now, ranked against each other since they're all the same currency:

The flat-dollar (and flat-mile) trap

A "$15 back" one-time bonus looks great next to "2%", until you notice it pays once and is usually restricted to your first purchase at that store, or to spending above some minimum in a single order. A flat amount is a fine bonus, but it isn't a rate:

• On a $50 order, "$15 back" is huge.
• On a $500 order, that same $15 works out to 3%, and a percentage rate scales with the order while the flat amount doesn't.

We never rank a one-time bonus as "better than" a recurring per-dollar rate. They're different products, and treating them as interchangeable steers you toward the wrong portal for a big purchase. The two kinds you'll meet most are a first-purchase bonus (a flat amount limited to your first order at that store through the portal) and a spend bonus (a flat amount that only pays once you cross a stated spending minimum in one order).

If the basics are new, start with cashback portals 101. On the cashback side, see how the best cashback portals actually rank once you account for how reliably they pay. And if you're weighing whether tracking any of this is worth the effort in the first place, we cover that separately in is cashback actually worth it.

For how today's number turns into a verdict once you've read the unit correctly, see how we decide a rate is good. Browse every portal we track to see how each one labels what it pays, open LEGO's full rate table for the live version of the table above, or check the glossary if a term here is new.