Unlike the SAT, the ACT does not provide you with a list of basic math formulas to rely upon at the beginning of the math test. This means you will need to be able to recall them. Below you will find lists of “Must Know” formulas, “Good to Know” formulas, and “Bonus” formulas to commit to memory for the ACT! Learn them all, then check out our list of ACT math topics to begin applying them!

*(Important note: occasionally, an ACT math problem may rely upon a more advanced formula, such as the surface area of a sphere. In these cases, the question itself will typically provide you with the formula you need. So no need to think you need to memorize everything. However, being able to recall basic formulas will ensure you can tackle problems that don’t provide a formula with confidence! The list below includes formulas for the concepts the ACT tests most frequently.)*

## Important ACT Math Formulas to Know (PDF)

Sometimes it’s easier to memorize formulas by studying a little bit every day. To make this easier, we created a downloadable, printable Magoosh ACT Math Formulas PDF.

Click here to download the free Math Formulas on the ACT PDF!

## Must Know ACT Math Formulas:

Though the ACT tests different concepts on each exam, there are popular topics that come up again and again. This list contains the best ACT math formulas to know, in addition to some extras (for all you over-achievers out there). Bonus: the math formulas on the ACT also appear in your high school math classes. So, you’re really studying for two things at once. Nice.

### Average:

S/T (Average = Sum/Number of things)

### Lines:

**Slope intercept form:**

y = mx + b (where m is the slope and b is the y-intercept)

**Slope:**

### Quadrilaterals:

**Perimeter of a rectangle:**

2l + 2w (where l is the length and w is the width)

**Area of a rectangle:**

lw (length x width)

**Volume of a box:**

lwh (length x width x height)

**Surface area of a rectangular solid:**

2lw + 2wh + 2lh

**Diagonal in a rectangular solid:**

Apply the Pythagorean theorem twice or

### Triangles:

**Area of a triangle:**

1/2bh (1/2 base x height)

### Circles and Spheres:

**Area of a circle:**

**Circumference of a circle:**

**Volume of a sphere:**

### Cylinders:

**Volume of a cylinder:**

### Pythagorean Theorem:

### Trigonometry:

**SOHCAHTOA:**

sin x = opposite/hypotenuse

cos x = adjacent/hypotenuse

tan x = opposite/adjacent

You should also know your quadrants and where sine, cosine, and tangent are positive or negative:

### Probability:

**Probability:**

Number of desired outcomes / number of total outcomes

**Factorials (e.g. 8!):**

To find the factorial of any integer, multiply it by every positive integer below it, e.g.:

8 x 7 x 6 x 5 x 4 x 3 x 2 x 1

## Formulas that are Good to Know

**Equation of a circle:**

**Volume of a cone:**

**Volume of a pyramid:**

**Arithmetic sequences:**

**Geometric sequences:**

### Logarithms

**Definition:**

**Change of base rule:**

### Trapezoids

**Area of a trapezoid:**

(Add the bases, divide by two, then multiply by the height.)

### 30-60-90 Triangle Ratio:

### 45-45-90 Triangle Ratio:

### Exponential Growth Formula:

Where P = principal (starting value), r = rate of growth, n = number of months, t = time in years, and A = new amount.

## Bonus Things to Know

### Quadratic Equation:

Often, you will be better off applying a strategy such as backsolving to solve a complicated algebra problem, but if you are comfortable with the quadratic equation, keep it in the back of your mind.

### Permutations:

### Combinations:

Let us know if you have any questions about these ACT formulas. 🙂

*Image Credit: hotmath.com and getmathhelp.jimdo.com*

Is there any more formula which is needed for the ACT?

Hi there 🙂 We’ve done our best to compile most, if not all, of the formulas you’ll want to be familiar with on test day. While we can’t guarantee that the list is exhaustive, if you know how to apply the formulas we listed, you should be well on your way to ACT Math success 😀