AP Biology equation sheet: every formula by topic.
Here is the full AP Biology equation sheet, rendered as readable text and grouped by topic. On exam day the College Board hands you this two-sided reference — the same AP Biology formula sheet you see below — at the front of both the multiple-choice and free-response sections, and you get a calculator too. So you never memorize the 23 formulas; you only have to know which one to reach for and how to use it.
Is the formula sheet provided on the AP Biology exam?
Yes. The College Board provides a two-sided Equations and Formulas reference sheet at the front of both the multiple-choice and free-response sections, so it is available to you for the entire exam. You are also allowed a four-function, scientific, or graphing calculator on both sections.
The sheet is a reference of statistics equations and a handful of biology formulas — mean, standard deviation, chi-square, Hardy–Weinberg, population growth, water potential, Gibbs free energy, pH, and surface area and volume — plus the variable keys and a couple of tables. It holds about 23 formulas in all. Because the math is handed to you, the exam tests whether you can pick the right relationship and apply it, not whether you memorized it. Everything on it is rendered as text below, grouped by topic.
The AP Biology formula sheet, by topic
Every relationship on the sheet, with its variable key and a one-line note on when to use it on the exam. Nothing here is a screenshot — it is all on-page text you can search, copy, and study from.
Statistics & probability
Compare your χ² value to the critical value at your degrees of freedom. If χ² is greater than the critical value at p = 0.05, the difference is significant and you reject the null hypothesis.
| Degrees of freedom (df) | p = 0.05 | p = 0.01 |
|---|---|---|
| 1 | 3.84 | 6.64 |
| 2 | 5.99 | 9.21 |
| 3 | 7.82 | 11.34 |
| 4 | 9.49 | 13.28 |
| 5 | 11.07 | 15.09 |
| 6 | 12.59 | 16.81 |
| 7 | 14.07 | 18.48 |
| 8 | 15.51 | 20.09 |
The sheet also lists the mode (most frequent value), median (middle value), range (maximum − minimum), and the laws of probability — multiply probabilities for independent events, add them for mutually exclusive events.
Hardy–Weinberg (population genetics)
Rate & population growth
Water potential
Gibbs free energy
pH
Metric prefixes
The sheet prints the standard SI prefixes for converting between units of measurement.
| Factor | Prefix | Symbol |
|---|---|---|
| 109 | giga | G |
| 106 | mega | M |
| 103 | kilo | k |
| 10−2 | centi | c |
| 10−3 | milli | m |
| 10−6 | micro | µ |
| 10−9 | nano | n |
| 10−12 | pico | p |
Surface area & volume (cell size)
Dividing surface area by volume gives the surface-area-to-volume ratio (SA:V). As a cell grows, volume rises faster than surface area, so the ratio falls — which is why cells stay small enough to exchange materials efficiently.
What’s NOT on the sheet (what you must still know)
The sheet gives you equations — it does not give you the biology. You still have to supply everything the formulas operate on, and a few relationships students often expect to find are not printed at all.
Not on the sheet: the photosynthesis and cellular-respiration equations, the shapes of the exponential J-curve and logistic S-curve (you get the growth equations, not the graphs), the pH/pOH rules such as pH + pOH = 14, the Q10 temperature logic, and every bit of biological content — processes, vocabulary, and the diagrams you read and label. In short, the sheet hands you the math, and you bring the mechanism: knowing when chi-square applies, what each Hardy–Weinberg term means, or why a cell with a low surface-area-to-volume ratio struggles. That reasoning is exactly what the free response rewards.
How to use the formula sheet on exam day
Treat the sheet as a map, not a safety net. Because you cannot study it cold under time pressure, practice with it open all year so you know where each formula lives and which question type it answers. Water potential, chi-square, Hardy–Weinberg, and population growth are the most-tested calculations, so rehearse those until the setup is automatic.
On test day, name the formula a question is asking for, pull it from the sheet, and use the variable key to match every symbol to a value before you compute. Watch your units — temperature in Kelvin for water potential, the right p-value column for chi-square — and show the setup, since the free response scores your reasoning, not just the final number. Drill the math one unit at a time with the AP Biology Progress Check answers, then pressure-test it on the free-response guide.
Get the official one-page sheet
To practice with the exact layout you will see on test day, pull the official two-sided Equations and Formulas sheet from the College Board’s AP Biology exam page. Reviewing the real document means there are no surprises about where each formula sits when the clock starts.
Frequently asked questions
Quick answers — written by humans, not a chatbot.
Is a formula sheet provided on the AP Biology exam?
Yes. The College Board gives you a two-sided Equations and Formulas sheet at the front of both the multiple-choice and free-response sections, so you have it for the whole exam, along with a calculator.
Do I have to memorize the formulas for AP Biology?
No. Every formula you need — including water potential and chi-square — is on the provided sheet. You are tested on knowing when and how to use each one, not on recalling them.
How many formulas are on the AP Biology formula sheet?
About 23, organized into statistics and probability, Hardy–Weinberg, rate and growth, water potential, Gibbs free energy, pH, and surface area and volume — plus variable keys, a chi-square table, and metric prefixes.
How do you calculate water potential?
Use Ψ = Ψp + Ψs, and find solute potential with Ψs = −iCRT (i = ionization constant, C = molar concentration, R = 0.0831 L·bar·mol⁻¹·K⁻¹, T = temperature in Kelvin). Water always moves from higher to lower water potential.
What is NOT on the AP Biology formula sheet?
The photosynthesis and cellular-respiration equations, the shapes of the exponential and logistic growth curves, the pH/pOH rules, and all biology content. The sheet gives equations only — you supply the biology.