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Cornwell Blake McKelvin
Wealth · Time · Compounding

Compounding Interest
Calculator

Every field updates results instantly. Results reflect A = P(1+r/n)ⁿᵗ + PMT formula.

Final Balance
at end of period
Your Inputs
Principal ($)$10,000
$
Annual Interest Rate (%)8.00%
%
Time Period (years)30 years
yrs
Compounds per Year
1=Annual · 4=Quarterly · 12=Monthly · 365=Daily
Monthly Contribution ($)$200
$
Live Results
Final Balance
Total Contributed
Interest Earned
Growth Multiple
Years to Double (Rule of 72)
From the Book — Bill & Linda
$200/mo · 16% · 40 yrs · Monthly — Click to load
$5,769,230
Cost Breakdown
Interest
Interest Earned
Contributed
Growth Over Time
01 Year-by-Year Projection
YearBalanceContributedInterest EarnedMultiple
02 Rule of 72 — Years to Double
Principal · Interest · Taxes · Insurance · PMI

Mortgage Calculator

Full PITI breakdown including PMI. Amortization schedule, payoff date, and extra payment savings.

Monthly Payment
P · I · T · I + PMI
Loan Inputs
Home Price$450,000
$
Down Payment20% — $90,000
$
Loan Term
Interest Rate (APR)6.75%
%
Property Tax (%/yr)
%
Home Insurance ($/yr)
$
HOA ($/mo)
$
Total Monthly Payment
Principal · Interest · Taxes · Insurance · PMI
P & I
Property Tax
Insurance
PMI
HOA
LTV Ratio
PMI applies. Down payment <20%. Private Mortgage Insurance (~0.5%/yr) added until LTV reaches 80%.
Loan Summary
Loan Amount
Total Interest
Total of All Payments
Payoff Date
Interest vs Principal
Interest
Total Interest
Principal
Down Payment
Balance & Equity Over Time
01 Amortization Schedule
Period Payment Principal Interest Cumul. Interest Balance
Full Loan Analysis

Loan Amortization
Calculator

Monthly, bi-weekly & weekly schedules. Extra payment impact, scenario comparison, printable table.

Payment
per period
Loan Parameters
Loan Amount$25,000
$
Annual Interest Rate7.50%
%
Loan Term5 years
yrs
Payment Frequency
Extra Payment / Period$0
$
First Payment Date
Payment/Period
monthly
Total Payments
periods
Total Interest
—% of cost
Total Cost
principal + interest
Last Payment
Effective APR
annual rate
Cost Breakdown
Interest
Interest
Principal
P vs I Per Period (first 36)
01 Amortization Schedule
Period Date Payment Principal Interest Cumul. Interest Balance
Debt · Payoff · Strategy

Credit Card
Payoff Calculator

Compare minimum payments vs fixed amounts vs avalanche/snowball strategies. See the true cost of carrying a balance.

Interest Saved
vs minimum payments
Card Details
Current Balance$5,000
$
Annual Interest Rate (APR)22.99%
%
Minimum Payment
%
Your Fixed Monthly Payment$200
$
Extra Monthly Payment$0
$
Min Payment Months
paying minimum only
Your Payment Months
at your fixed amount
Min Payment Interest
total interest paid
Your Payment Interest
total interest paid
Interest Saved
vs minimum payments
Time Saved
months earlier payoff
Balance Over Time — Strategy Comparison
Payoff Schedule
Month Payment Principal Interest Balance
Retirement · Growth · Income

Retirement Savings
Calculator

Project your 401k/IRA balance at retirement, estimate monthly income, and see when your money runs out.

At Retirement
projected balance
Your Details
Current Age35
Retirement Age65
Current Savings$50,000
$
Monthly Contribution$500
$
Employer Match (%)3%
%
Annual Return Rate7%
%
Retirement Duration (years)25 yrs
yrs
Balance at Retirement
projected portfolio
Monthly Income (4%)
safe withdrawal rate
Total Contributed
yours + employer
Employer Match Total
free money earned
Years to Grow
until retirement
Money Lasts Until
at 4% withdrawal
Portfolio Growth to Retirement
Real Estate · Decision · Analysis

Rent vs Buy
Calculator

True total-cost comparison over your chosen time horizon, including opportunity cost, appreciation, and tax benefits.

Break-Even
year buying wins
Buying Costs
Home Price
$
Down Payment (%)
%
Mortgage Rate
%
Loan Term
yrs
Property Tax (%/yr)
%
Home Insurance ($/yr)
$
Maintenance (%/yr)
%
Home Appreciation (%/yr)
%
Renting Costs
Monthly Rent
$
Annual Rent Increase
%
Renter's Insurance ($/yr)
$
Investment Return on Down Payment (%/yr)
%
Opportunity cost of down payment if invested
Comparison Period
yrs
Marginal Tax Rate
%
Total Buy Cost
over comparison period
Total Rent Cost
total rent paid
Home Value at End
after appreciation
Equity Built
mortgage paydown + appreciation
Net Buy Advantage
positive = buying wins
Break-Even Year
when buying becomes cheaper
Cumulative Cost: Renting vs Buying Over Time
Goals · Timeline · Savings

Goal Savings
Calculator

How much do you need to save each month to hit your goal? Enter a target and let the math work backward.

Monthly Required
to reach your goal
Goal Details
Goal Amount$20,000
$
Current Savings (head start)$0
$
Time to Goal3 years
yrs
Annual Interest Rate5%
%
Compounding
Monthly Savings Needed
to reach goal on time
Weekly Savings Needed
equivalent
Total You Contribute
cash out of pocket
Interest Earned
money working for you
Goal Date
projected completion
Savings Rate
interest % of goal
Savings Growth to Goal
Scenario Comparison — Different Timelines
Inflation · Purchasing Power · Time

Inflation &
Purchasing Power

How much is your money really worth over time? Calculate the real impact of inflation forward or backward.

Future Value
what it costs later
Inputs
Amount$1,000
$
Annual Inflation Rate3%
%
Historical US average ~3.2% · Fed target 2%
Time Period10 years
yrs
Direction
Quick Presets — Common Inflation Rates
Future Cost
what you'll need
Purchasing Power Lost
value eroded
Power Lost (%)
of original value
Real Value Halves In
Rule of 70
Required Savings Return
to maintain real value
Equivalent in Dollars
purchasing power now
Purchasing Power Erosion Over Time
01 Year-by-Year Breakdown
Year Future Cost Purchasing Power Power Lost Cumulative Inflation