Success TutoringWorksheets
Study Guide11th GradeLevel 2 · Standard

Free 11th Grade Simple and Compound Interest

A senior study guide comparing simple interest (I = Prn) with compound interest (A = P(1 + r)ⁿ), including compounding more often than once a year. Worked examples find the final amount, the interest earned, the principal needed to reach a target, the time for money to double and the rate from a known growth, with a six-question self-check and answers.

Download Free PDF

Instant download · No sign-up · Free for personal, classroom and homeschool use

Grade
11th Grade
Subject
Math
Topic
Financial Math
Difficulty
Level 2 · Standard
Estimated time
25 minutes
Curriculum
Texas grade levels (TEKS)
Answers
Not applicable
Format
PDF (A4) + print

Students will practice

  • calculating simple interest and the final amount with I = Prn
  • calculating compound interest with A = P(1 + r)ⁿ, matching the rate to the compounding period
  • finding the principal or the time needed to reach a target amount
  • comparing simple and compound interest over the same period

Curriculum: Texas grade levels (TEKS). We show specific outcome codes only where they have been verified against the official curriculum document.

What's next?

Completed: Simple and Compound Interest

  1. 111th Grade Simple and Compound Interest Worksheet — Level 1
  2. 211th Grade Simple and Compound Interest Worksheet — Level 2
  3. 311th Grade Simple and Compound Interest Worksheet — Level 3
Study guide

How to use this study guide

  1. Read it together first, pausing at each worked example to try the step before reading the answer.
  2. Attempt the "Check yourself" questions at the end without looking back.
  3. Then practice with a worksheet from the pathway above and finish with the topic test.

Common questions

Who is this study guide for?

11th Grade students (typically ages 16–17) working on financial math. It is pitched at level 2 · standard.

Are the answers included?

This is a study guide, so there is no separate answer sheet; the 'Check yourself' questions include answers.

How long does it take?

About 25 minutes. Short, regular sessions work best: two or three a week beats one long one.

Do I need to sign up to download?

No. Click Download Free PDF and it opens immediately. It is free for personal, classroom and homeschool use.

What should we do next?

Try 11th Grade Simple and Compound Interest Worksheet — Level 1.

Preview

Success TutoringWorksheets11th Grade · Mathematics · Financial Mathematics

Simple and Compound Interest

What you need to know

Simple interest is paid on the original amount (the principal) only, so the same dollar amount is added every period: I = Prn, where P is the principal, r is the interest rate per period as a decimal and n is the number of periods. The final amount is A = P + I.

Compound interest is paid on the principal and on interest already earned, so the balance grows faster each period: A = P(1 + r)[sup n], and the interest earned is I = A − P. The key skill is matching r and n to the compounding period: for 6% per year compounded monthly, r = 0.06 ÷ 12 = 0.005 per month and n counts months.

Nominal rateCompoundedr per periodn for 2 years
6% per yearannually0.062
6% per yearhalf-yearly0.034
6% per yearquarterly0.0158
6% per yearmonthly0.00524

Simple interest: $5000 at 4% per year simple interest for 3 years

  1. I = Prn = 5000 × 0.04 × 3 = $600
  2. A = 5000 + 600 = $5600

Compound interest: $5000 at 4% per year compounded annually for 3 years

  1. A = P(1 + r)n = 5000 × 1.043 = 5000 × 1.124864 = $5624.32
  2. Interest earned: 5624.32 − 5000 = $624.32, which is $24.32 more than simple interest over the same 3 years. The gap grows quickly with more years.

Monthly compounding: $8000 at 6% per year compounded monthly for 2 years

  1. r = 0.06 ÷ 12 = 0.005 per month; n = 2 × 12 = 24 months
  2. A = 8000 × 1.00524 = 8000 × 1.12716… = $9017.28
  3. Interest: 9017.28 − 8000 = $1017.28

Find the principal: how much must be invested now at 5% per year compounded annually to have $20,000 in 5 years?

  1. 20,000 = P × 1.055
  2. P = = = $15,670.52
  3. This is sometimes called the present value of $20,000.

Find the time: how long does $1000 take to double at 7% per year compounded annually?

  1. 1000 × 1.07n = 2000, so 1.07n = 2
  2. Take logs: n ln 1.07 = ln 2, so n = = = 10.24…
  3. Interest is only added at the end of each year, so it takes 11 years to be at least double. (You can also find this by trial and error with the table function on a calculator.)

Find the rate: $3000 grows to $3600 in 4 years with annual compounding. What is the rate?

  1. 3000(1 + r)4 = 3600, so (1 + r)4 = 1.2
  2. 1 + r = 1.21/4 = 1.0466…
  3. r = 0.0466…, so the rate is 4.66% per year (to 2 decimal places)
Common mistake: using the annual rate with a number of months. The rate and the number of periods must describe the same period. 6% per year monthly for 2 years is r = 0.005 and n = 24, never r = 0.06 and n = 24. Another common mistake: rounding too early. Keep 1.00524 in your calculator (or at least 6 decimal places) until the final step, then round money to the nearest cent. Rounding 1.12716 to 1.13 changes the answer by more than $20.

Check yourself

  1. Find the simple interest on $2000 at 5% per year for 4 years.
  2. Find the final amount when $2000 is invested at 5% per year compounded annually for 4 years.
  3. Find the final amount when $10,000 is invested at 3% per year compounded monthly for 1 year.
  4. How much must be invested now at 6% per year compounded annually to have $5000 in 3 years?
  5. How many whole years does it take money to at least double at 10% per year compounded annually?
  6. Find the interest earned on $1500 at 8% per year compounded quarterly for 2 years.

Answers: 1. 2000 × 0.05 × 4 = $400 2. 2000 × 1.054 = $2431.01 3. 10,000 × 1.002512 = $10,304.16 4. 5000 ÷ 1.063 = $4198.10 5. n = ln 2 ÷ ln 1.1 = 7.27…, so 8 years 6. 1500 × 1.028 = $1757.49, so interest = $257.49

Free worksheets at worksheets.successtutoring.com · © Success Tutoring · Free for personal and classroom use

Preview — the PDF contains the full resource.

More 11th Grade financial math resources

  • Worksheet

    11th Grade Simple and Compound Interest Worksheet — Level 1

    Calculate simple interest with I = Prn, then compound interest with A = P(1 + r)ⁿ, and compare the two. Builds confidence with the core…

    Difficulty
    Level 1 · Easier
    Time
    20 min
    Questions
    8 questions
    Answers
    Answers included
  • Worksheet

    11th Grade Simple and Compound Interest Worksheet — Level 2

    Calculate simple interest with I = Prn, then compound interest with A = P(1 + r)ⁿ, and compare the two. Expected-level practice for this…

    Difficulty
    Level 2 · Standard
    Time
    20 min
    Questions
    8 questions
    Answers
    Answers included
  • Worksheet

    11th Grade Simple and Compound Interest Worksheet — Level 3

    Calculate simple interest with I = Prn, then compound interest with A = P(1 + r)ⁿ, and compare the two. A challenge set for students ready…

    Difficulty
    Level 3 · Challenge
    Time
    20 min
    Questions
    8 questions
    Answers
    Answers included

Financial Math in other year levels

Was this resource helpful?

About this resource

Created by
Success Tutoring
Last reviewed
1 October 2026
How it was made
Written by our team

Free to print and share for personal, classroom and homeschool use. Please don't resell. Spotted an error? Let us know.