Percentage Calculators - Help & Documentation

How to Use

• Enter the desired percentage (X) into the first input field.
• Enter your main number (Y) into the second input field.
• Optionally, check the "Round" box to round the result to two decimal places.
• The calculated result is shown instantly as you type.
• Click "Add to Memos" or press Enter to save your calculation.

How It Works

The Basic Percentage calculator uses this formula:

For example, to find 15% of 200, the calculator computes:

So the result is 30.

Practical Uses

• Finding sale discounts (e.g., 20% off an $80 product).
• Calculating taxes (e.g., 8% tax on a $250 item).
• Checking grades (e.g., 85% of total points).
• Measuring nutritional intake (e.g., 40% daily value).
• Determining tips at restaurants (e.g., 15% tip on a $60 bill).
• Calculating interest (e.g., 5% annual interest on a $1000 investment).

How to Use

1. Enter the percentage (X) in the first input field.
2. Enter the result value (Z) in the second input field.
3. Optionally, check the "Round" box to round the result to two decimal places.
4. The calculator will instantly show the original value (Answer).
5. Click "Add to Memos" or press Enter to save your calculation.

How It Works

The Original Value calculator uses this formula:

For example, if 25% of some value is 50, the original value would be:

So the original value is 200.

When to Use

• Finding the original price before a discount was applied
• Calculating the total amount before tax when you know the tax percentage and tax amount
• Determining the original value when you know what percentage of it equals a specific amount
• Figuring out the original salary when you know the percentage raise and new salary
• Finding the original investment amount when you know the percentage return and final value

How to Use

• Enter the total value (Y) in the first input field (after "of").
• Enter the partial value (Z) in the second input field (after "is").
• The calculator will instantly show what percentage of Y is Z.
• Optionally, check the "Round" box to round the result to two decimal places.
• Click "Add to Memos" or press Enter to save your calculation.

How It Works

The Part-to-Whole Percentage calculator uses this formula:

For example, to find what percentage 25 is of 100, the calculator computes:

So 25 is 25% of 100.

Practical Uses

• Calculating test scores (e.g., how many points you got out of the total).
• Determining market share (e.g., a company's sales compared to total industry sales).
• Analyzing budget allocations (e.g., how much of your budget goes to a specific expense).
• Measuring progress toward goals (e.g., current savings compared to savings target).
• Calculating completion percentage (e.g., tasks completed out of total tasks).
• Determining batting averages in sports (e.g., hits divided by at-bats).

How to Use

• Enter the original (old) value in the first input field.
• Enter the new value in the second input field.
• Optionally, check the "Round" box to round the result to two decimal places.
• The calculator will instantly show the percentage change.
• A positive result indicates an increase; negative indicates a decrease.
• Click "Add to Memos" or press Enter to save your calculation.

How It Works

The Percentage Change calculator uses this formula:

For example, if a value increases from 50 to 75, the calculator computes:

This shows a 50% increase from the original value.

Practical Uses

• Monitoring stock price changes over time.
• Evaluating salary increases or decreases.
• Tracking weight loss or gain percentages.
• Analyzing business revenue growth year-over-year.
• Assessing performance improvements in sports or academics.
• Calculating inflation rates by comparing prices over time.
• Measuring changes in website traffic or conversion rates.

How to Use

• Enter the original value into the first input field.
• Enter the percentage increase into the second input field.
• Optionally, check the "Round" box to round the result to two decimal places.
• The calculated new value is shown instantly as you type.
• Click "Add to Memos" or press Enter to save your calculation.

How It Works

The Increased Value calculator uses this formula:

For example, to find the new value when $1,000 is increased by 15%, the calculator computes:

So the new value is $1,150.

Practical Examples

• Salary Increase: If your $50,000 salary increases by 8%, your new salary will be $54,000.
• Price Inflation: A $120 item with 5% price increase becomes $126.
• Investment Growth: A $2,000 investment growing by 12% becomes $2,240.
• Population Growth: A city of 100,000 people with 3% growth reaches 103,000.
• Rent Increase: Monthly rent of $1,200 with a 7% increase becomes $1,284.
• Budget Allocation: A $5,000 marketing budget increased by 25% becomes $6,250.

How to Use

• Enter the percentage increase into the first input field.
• Enter the new value (after increase) into the second input field.
• Optionally, check the "Round" box to round the result to two decimal places.
• The calculated original value is shown instantly as you type.
• Click "Add to Memos" or press Enter to save your calculation.

How It Works

The Original Before Increase calculator uses this formula:

For example, to find the original value when the new value is $1,150 after a 15% increase, the calculator computes:

So the original value was $1,000.

Important Note

When the increase percentage is -100%, the calculation is undefined because you cannot divide by zero. The calculator will show an error message in this case.

Practical Examples

• Reverse Salary Calculation: If a new salary is $54,000 after an 8% increase, the original salary was $50,000.
• Original Price Analysis: If an item costs $126 after a 5% price increase, the original price was $120.
• Investment Principal: If an investment is worth $2,240 after 12% growth, the original investment was $2,000.
• Pre-Growth Population: If a city has 103,000 people after 3% growth, the original population was 100,000.
• Original Rent: If rent is now $1,284 after a 7% increase, the original rent was $1,200.
• Base Budget: If a budget is $6,250 after a 25% increase, the original budget was $5,000.

How to Use

• Enter the original value into the first input field.
• Enter the percentage decrease into the second input field.
• Optionally, check the "Round" box to round the result to two decimal places.
• The calculated new value is shown instantly as you type.
• Click "Add to Memos" or press Enter to save your calculation.

How It Works

The Decreased Value calculator uses this formula:

For example, to find the new value when $800 is decreased by 20%, the calculator computes:

So the new value is $640.

Practical Examples

• Sale Discount: A $300 jacket with a 30% discount costs $210.
• Weight Loss: If you weigh 180 lbs and lose 15%, your new weight is 153 lbs.
• Budget Cut: A $10,000 department budget cut by 25% becomes $7,500.
• Stock Price Drop: A $45 stock declining by 12% becomes $39.60.
• Energy Savings: A $200 monthly bill reduced by 18% becomes $164.
• Employee Reduction: A 500-person workforce reduced by 10% becomes 450 people.

How to Use

• Enter the percentage decrease into the first input field.
• Enter the new value (after decrease) into the second input field.
• Optionally, check the "Round" box to round the result to two decimal places.
• The calculated original value is shown instantly as you type.
• Click "Add to Memos" or press Enter to save your calculation.

How It Works

The Original Before Decrease calculator uses this formula:

For example, to find the original value when the new value is $950 after a 5% decrease, the calculator computes:

So the original value was $1,000.

Important Note

When the decrease percentage is 100%, the calculation is undefined because you cannot divide by zero. The calculator will show an error message in this case.

Practical Examples

• Reverse Price Calculation: If an item costs $95 after a 5% discount, the original price was $100.
• Original Salary Analysis: If a reduced salary is $46,000 after a 8% cut, the original salary was $50,000.
• Investment Principal: If an investment is worth $1,760 after a 12% loss, the original investment was $2,000.
• Pre-Decline Population: If a city has 97,000 people after a 3% decline, the original population was 100,000.
• Original Expense: If expenses are now $930 after a 7% reduction, the original expenses were $1,000.
• Base Budget: If a budget is $3,750 after a 25% decrease, the original budget was $5,000.