The Federal Circuit uses the 13 DuPont factors:

1. The similarity or dissimilarity of the marks in their entireties as to appearance, sound, connotation and commercial impression;
2. The similarity or dissimilarity and nature of the goods or services as described in an application or registration or in connection with which a prior mark is in use;
3. The similarity or dissimilarity of established, likely-to-continue trade channels;
4. The conditions under which and buyers to whom sales are made, i.e. "impulse" vs. careful, sophisticated purchasing;
5. The fame of the prior mark (sales, advertising, length of use);
6. The number and nature of similar marks in use on similar goods;
7. The nature and extent of any actual confusion;
8. The length of time during and conditions under which there has been concurrent use without evidence of actual confusion;
9. The variety of goods on which a mark is or is not used (house mark, "family" mark, product mark);
10. The market interface between applicant and the owner of a prior mark;
11. The extent to which applicant has a right to exclude others from use of its mark on its goods;
12. The extent of potential confusion, i.e., whether de minimis or substantial; and

Any other established fact probative of the effect of use. In re E.I. du Pont de Nemours & Co., 476 F.2d 1357, 1361 (C.C.P.A. 1973). However, when reviewing trademark infringement over which it does not have exclusive jurisdiction, the Federal Circuit uses the law of the applicable Circuit. Bandag, Inc. v. Al Bolser's Tire Stores, Inc., 750 F.2d 903, 909 (Fed. Cir. 1984).

The District of Columbia District Court uses the following seven factors:

1. the strength of the plaintiff's mark;
2. the degree of similarity between the two marks;
3. the proximity of the products;
4. evidence of actual confusion;
5. the defendant's purpose or reciprocal good faith in adopting its own mark;
6. the quality of defendant's product; and
7. the sophistication of the buyers.

Globalaw Ltd. v. Carmon & Carmon Law Office, 452 F. Supp. 2d 1, 48 (D.D.C. 2006). It does not appear that the D.C. Circuit has adopted a test yet.

The First Circuit considers the eight factors:

1. the similarity of marks;
2. the similarity of the goods (or, in a service mark case, the services);
3. the relationship between the parties' channels of trade;
4. the juxtaposition of their advertising;
5. the classes of prospective purchasers;
6. he evidence of action confusion;
7. the defendant's intent in adopting its allegedly infringing mark; and
8. the strength of the plaintiff's mark.

As set forth in Pignons S.A. de Mecanique de Precision v. Polaroid Corp., 657 F.2d 482, 487 (1st Cir. 1981).

The Second Circuit considers the eight factors:

1. strength of the trademark;
2. similarity of marks;
3. proximity of the products and their competitiveness with one another;
4. evidence that the senior user may bridge the gap by developing a product for sale in the market of the alleged infringer's product;
5. evidence of actual consumer confusion;
6. evidence that the imitative mark was adopted in bad faith;
7. respective quality of the products; and
8. sophistication of consumers in the relevant market.

As set forth in Polaroid Corp. v. Polarad Electronics Corp., 287 F.2d 492, 495 (2d Cir. 1961).   

The Third Circuit considers the ten factors:

1. the degree of similarity between the owner's mark and the alleged infringing mark;
2. the strength of the owner's mark;
3. the price of the goods and other factors indicative of the care and attention expected of consumers when making a purchase;
4. the length of time the defendant has used the mark without evidence of actual confusion arising;
5. the intent of the defendant in adopting the mark;
6. the evidence of actual confusion;
7. whether the goods, though not competing, are marketed through the same channels of trade and advertised through the same media;
8. the extent to which the targets of the parties' sales efforts are the same;
9. the relationship of the goods in the minds of consumers because of the similarity of function; and
10. other facts suggesting that the consuming public might expect the prior owner to manufacture a product in the defendant's market, or that he is likely to expand into that market.

As set forth in Interpace Corp. v. Lapp, Inc., 721 F.2d 460, 463 (3d Cir. 1983).

The Fourth Circuit considers nine factors in determining likelihood of confusion:

1. the strength or distinctiveness of the plaintiff's mark as actually used in the marketplace;  
2. the similarity of the two marks to consumers;
3. the similarity of the goods or services that the marks identify;
4. the similarity of the facilities used by the markholders;
5. the similarity of advertising used by the markholders;
6. the defendant's intent;
7. actual confusion;
8. the quality of the defendant's product; and
9. the sophistication of the consuming public.  

George & Co., LLC v. Imagination Entm't Ltd., 575 F.3d 383, 393 (4th Cir. 2009). The first seven factors were set forth Pizzeria Uno Corp. v. Temple, 747 F.2d 1522, 1527 (4th Cir. 1984).  The last two factors were added in Sara Lee Corp v. Kayser-Roth Corp., 81 F.3d 455, 463-64 (4th Cir. 1996).

The Fifth Circuit uses eight factors:

1. strength of the plaintiff's mark;
2. similarity of design between the marks;
3. similarity of the products;
4. identity of retail outlets and purchasers;
5. similarity of advertising media used;
6. the defendant's intent;
7. actual confusion; and
8. degree of care exercised by potential purchasers.

Am. Rice Inc. v. Producers Rice Mill, Inc., 518 F.3d 321, 329 (5th Cir. 2008).

The Sixth Circuit uses the eight factors:

1. strength of the plaintiff's mark;
2. relatedness of the products;
3. similarity of the marks;
4. evidence of actual confusion;
5. parties' marketing channels;
6. likely degree of purchaser care;
7. defendant's intent in selecting the mark; and
8. probability that the product lines will expand.

As set forth in Frisch's Rest., Inc. v. Shoney's Inc., 759 F.2d 1261, 1264 (6th Cir. 1985)

The Seventh Circuit uses seven factors:

1. the similarity between the marks in appearance and suggestion;
2. the similarity of the products;
3. the area and manner of concurrent use;
4. the degree of care likely to be exercised by consumers;
5. the strength of the plaintiff's mark;
6. any evidence of actual confusion; and
7. the intent of the defendant to palm off his product as that of another.

Sorensen v. WD-40 Co., 792 F.3d 712, 726 (7th Cir. 2015).

The Eighth Circuit considers the following six factors:

1. the strength of the trademark;
2. the similarity between the mark at issue and the alleged infringer's mark;
3. the degree to which the products compete with each other;
4. the alleged infringer's intent in using the mark;
5. incidents of actual confusion; and
6. whether the degree of purchaser care can eliminate the likelihood of confusion which would otherwise exist.

Lovely Skin, Inc. v. Ishtar Skin Care Products, LLC, 745 F.3d 877, 887-89 (8th Cir. 2014); SquirtCo v. Seven-Up Co., 628 F.2d 1086, 1091 (8th Cir. 1980).

The Ninth Circuit uses the following eight factors:

1. the strength of the mark;
2. the proximity of the goods;
3. the similarity of the marks;
4. evidence of actual confusion;
5. the marketing channels used;
6. the type of goods and the degree of care likely to be exercised by the purchaser;
7. the defendant's intent in selecting the mark; and
8. the likelihood of expansion of the product lines.

AMF Inc. v. Sleekcraft Boats, 599 F.2d 341, 348-49 (9th Cir.1979).

The Tenth Circuit uses the following six factors:

1. the degree of similarity between the marks;
2. the intent of the alleged infringer in using the mark;
3. evidence of actual confusion;
4. similarity of products and manner of marketing;
5. the degree of care likely to be exercised by purchasers; and
6. the strength or weakness of the mark.

Sally Beauty Co., Inc. v. Beautyco, Inc., 304 F.3d 964, 972 (10th Cir. 2002) (citing King of the Mountain Sports, Inc. v. Chrysler Corp., 185 F.3d 1084, 1089-90 (10th Cir. 1999)).

The Eleventh Circuit uses the following seven factors:

1. the strength of the plaintiff's mark;
2. the similarity between the plaintiff's mark and the allegedly infringing mark;
3. the similarity between the products and services offered by the plaintiff and defendant;
4. the similarity of the sales methods;
5. the similarity of advertising methods;
6. the defendant's intent, e.g., does the defendant hope to gain competitive advantage by associating his product with the plaintiff's established mark; and
7. actual confusion.

Alliance Metals, Inc., of Atlanta v. Hinely Indus., Inc., 222 F.3d 895, 907 (11th Cir. 2000)