What is the Kelly Criterion and how is it calculated?

The Kelly Criterion determines optimal position sizing based on win rate and average win/loss ratio. Formula: f = (bp - q) / b, where b = odds received, p = probability of winning, q = probability of losing.

How do I calculate position size for risk management?

Position size = (Account Size × Risk Percentage) / (Entry Price - Stop Loss Price). This ensures you never risk more than your predetermined percentage per trade.

What is a good profit factor in trading?

A profit factor above 1.5 is considered good, above 2.0 is excellent. It's calculated as Gross Profit / Gross Loss, measuring the profitability of your trading strategy.

How do trading costs affect my returns?

Trading costs (spreads, commissions, slippage) reduce net returns. Our calculator shows both gross and net P&L to help you understand the true cost of trading and optimize your strategy.

Free Trading Percentage Calculator

Free calculator for percentage changes, ROI, profit/loss ratios, and analyze investment returns. Essential for tracking trading performance and making informed investment decisions. Perfect complement to our position size calculator and profit/loss analysis tools.

Multiple Calculations

ROI Analysis

Instant Results

Percentage & ROI Calculator

Enter your values to calculate percentage changes, returns on investment, and analyze trading performance.

Price Change Calculator

Calculate percentage change between old and new prices

Original Price ($)

New Price ($)

Investment Amount ($)

Percentage Change

Price movement percentage

Absolute Change

$0.00

Dollar amount change

Profit/Loss

$0.00

P&L on investment

New Investment Value

$0.00

Updated portfolio value

Calculation Formula

Percentage Change: ((New Price - Old Price) / Old Price) × 100

Example: ((110 - 100) / 100) × 100 = 10%

Return on Investment (ROI) Calculator

Calculate ROI based on initial investment and current value

Initial Investment ($)

Current Value ($)

Time Period (months)

Total ROI

Overall return percentage

Annualized ROI

Annual return rate

Total Gain/Loss

$0.00

Dollar amount gained/lost

Monthly Return

Average monthly return

Percentage Of Calculator

Calculate what percentage one number is of another

Part (smaller number)

Whole (total number)

Percentage

What % the part is of the whole

Fraction

0/0

Expressed as a fraction

Decimal

0.00

Expressed as a decimal

Percentage Increase/Decrease Calculator

Apply a percentage increase or decrease to a number

Base Number

Percentage (%)

Operation

Result

0.00

Final number after operation

Change Amount

0.00

Absolute change in value

Multiplier

1.00

Factor applied to base

Professional Trading Calculator

Advanced trading calculations with costs, position sizing, and risk metrics

Entry Price ($)

Exit Price ($)

Position Size (shares/units)

Leverage (1x = no leverage)

Spread Cost ($)

Commission ($)

Gross P&L

$0.00

Before costs

Net P&L

$0.00

After all costs

Gross ROI

Return before costs

Net ROI

Return after costs

Total Capital Used

$0.00

Including leverage

Leverage Impact

Amplified return

Account Size ($)

Risk per Trade (%)

Entry Price ($)

Stop Loss ($)

Take Profit ($)

Risk Amount

$0.00

Maximum loss allowed

Position Size

Shares/units to buy

Risk per Share

Entry - Stop Loss

Reward per Share

Take Profit - Entry

Risk:Reward Ratio

1:0

Risk vs reward

Potential Profit

$0.00

If take profit hit

Winning Trades

Losing Trades

Average Win ($)

Average Loss ($)

Largest Loss ($)

Account Balance ($)

Win Rate

Percentage of winning trades

Profit Factor

0.00

Gross profit / Gross loss

Expected Value

$0.00

Average expected per trade

Kelly Criterion

Optimal position size

Maximum Drawdown

Largest loss vs account

Risk of Ruin

Probability of losing all

Understanding Percentage Calculations

Price Change Analysis

Essential for tracking asset performance
Helps identify trends and market movements
Critical for risk management decisions
Used in technical analysis and charting

ROI Calculations

Measures investment efficiency and profitability
Compares performance across different assets
Annualized returns for fair comparisons
Helps in portfolio optimization

Common Use Cases

Stop Loss: Calculate % loss thresholds
Profit Targets: Set percentage gain goals
Portfolio Analysis: Track overall performance
Risk Assessment: Measure position sizing

Real Trading Examples

Stock Price Movement

Scenario: Apple stock moves from $150 to $165

Price Change: $165 - $150 = $15

Percentage: ($15 ÷ $150) × 100 = 10%

Result: +10% gain

Forex Trade Analysis

Scenario: EUR/USD trade with $1000 investment

Entry: 1.1200

Exit: 1.1350 (+150 pips)

Result: +1.34% gain = $13.40

Crypto Investment ROI

Scenario: Bitcoin investment over 6 months

Initial: $5,000 investment

Current: $6,500 value

ROI: 30% (60% annualized)

Frequently Asked Questions

How do I calculate percentage change for trading?

Use the formula: ((New Price - Old Price) / Old Price) × 100. This gives you the percentage change, positive for gains and negative for losses. Multiply by your position size to get profit/loss.

What's the difference between ROI and percentage change?

Percentage change measures price movement of an asset, while ROI measures the return on your investment including any costs, fees, and the actual amount invested.

How do I annualize my returns?

To annualize returns, use: ((Current Value / Initial Investment)^(12/months) - 1) × 100. This accounts for compounding and gives you a standardized annual comparison.

Should I use simple or compound returns?

For single trades, use simple percentage change. For portfolio tracking over time, compound returns are more accurate as they account for reinvestment of gains.

Optimize Your Trading Performance

Now that you can calculate your returns, combine these insights with our position sizing and risk management calculators, then take your trading to the next level with our AI-powered indicator.

Get Infinity Algo More Conversion Tools