1. The total times are:
SAT -3 hours without essay and 3 hours 50 minutes with essay
ACT- 2 hours 55 minutes without writing and 3 hours 35 minutes with writing

 

2. The order of sessions. This can be important as doing the subject you find more difficult early on may be better. The order of subjects is:
SAT - Reading, writing, and language, math (no calculator), math (calculator), and essay (optional)
ACT – English, math, reading, science, writing (optional)

 

3. The number of questions:
SAT - Reading: 52 questions, writing and language: 44 questions, math (no calculator): 20 questions, math (calculator): 38 questions, essay (optional): 1 essay
ACT -English: 75 questions, math: 60 questions, reading: 40 questions, science: 40 questions, writing (optional): 1 essay

 

4. The time per section. Evaluate the time available in conjunction with the number of questions to be answered:
SAT - Reading: 65 mins, writing, and language: 35 mins, math (no calculator): 25 mins, math (calculator): 55 mins, essay (optional): 50 mins
ACT - English: 45 mins, math: 60 mins, reading: 35 mins, science: 35 mins, writing (optional): 40 mins

 

5. Scoring systems:
SAT –The evidence-based reading and writing (EBRW) and math sections have a scale of 200 to 800 each so the total score range is 400 to 800. The optional essay, which does not count towards your final score, uses three scales of 1 to 8.
ACT –Each of the four sections has a scale of 1 to 36, and your total score is the average of the four sections’ scores. The optional writing section, which does not count towards your final score, has a scale of 2 to 12.

 

6. Science:
SAT – There is no specific science section
ACT –There is one section that is only on science.

 

7. Math:
SAT – There are two math sections, and in one of them, no calculator may be used.
ACT- Calculators may be used for all math questions.

 

From https://www.catalyzecenter.com/