Delta SkyMiles Blue vs Delta SkyMiles Platinum

Every figure below is from the same dataset Miles computes its recommendations from. Rows the two cards agree on are collapsed at the bottom.

Economics

Dollar figures are per year unless the row says otherwise. Ongoing annual value is Miles' estimate of what the card adds per year after its annual fee: statement credits discounted for realistic use, benefits, and earning above a strong flat-rate card on a typical spending profile. First-year value is a separate net figure that includes the welcome bonus. A welcome bonus shown at its advertised maximum may not be available to every applicant; that figure is not marked as stronger. ★ marks the stronger comparable figure on other rows, and no row is marked when either figure is unknown.
Figure	Delta SkyMiles Blue American Express	Delta SkyMiles Platinum American Express
Annual fee	Best: $0 $350/yr less	$350
Ongoing annual value, after fee	$102	Best: $305 $203/yr more
First-year value	$108	$1,127 At the advertised maximum
Authorized user fee	—Unknown	—Unknown

Sign-up Bonus

The current welcome offer as recorded in the dataset. No winner is marked: a bonus is points times a valuation times a spend requirement you may or may not clear, and the first-year value above already prices it.
Offer	Delta SkyMiles Blue American Express	Delta SkyMiles Platinum American Express
Current offer	10K miles after $1K spend in the first 6 months	Apply and find out your welcome offer: As high as 90K bonus miles + earn a $300 statement credit after you spend $4k in eligible purchases on your new card within the first 6 months of card membership. You may not be eligible for the maximum welcome offer amount. Terms apply. (Offer Expires 11/4/2026)

Earning

Percentages are the return on a dollar spent: the multiplier times what Miles values those points at. ★ marks the higher return on a row. Categories only one card earns a bonus on are marked for that card; the other earns its base rate.
Category	Delta SkyMiles Blue American Express	Delta SkyMiles Platinum American Express
Hotels booked directly with hotels	—Unknown	Best: 3X3.3%
US Supermarkets	—Unknown	Best: 2X2.2%
Delta purchases	2X2.2%	Best: 3X3.3%

Benefits

Statement credits, lounge access and elite status as listed in the dataset; protections are counted, not listed. No winner is marked: twelve small credits are not more than two large ones, and the row that prices them, ongoing annual value, is under Economics.
Benefit	Delta SkyMiles Blue American Express	Delta SkyMiles Platinum American Express
Statement credits	—Unknown	Rideshare: $10 (Monthly) Resy: $10 (Monthly) Delta Stays: $150 (Annual Cardmember Year) Global Entry/TSA PreCheck: $120 (Every 4 Years)
Lounge access	—Unknown	—Unknown
Elite status	—Unknown	Delta SkyMiles
Protections	3	6

The same on both cards (7)

Rows where both cards state the same figure or the same earning rate. Nothing is marked, because there is no stronger side.
Fact	Delta SkyMiles Blue	Delta SkyMiles Platinum
Foreign transaction fee	None	None
Issuer	American Express	American Express
Rewards currency	Delta SkyMiles	Delta SkyMiles
Card type	Personal	Personal
Network	American Express	American Express
All other purchases	1X1.1%	1X1.1%
Dining	2X2.2%	2X2.2%

Which one is right for you

This page shows the difference. It does not pick: the winner depends on what you spend and what you already hold, and adding these figures up without knowing that would be a guess dressed as a verdict. Ask Miles and it computes the answer against your own wallet.

Ask Miles which to get