how to calculate improvement percentage

What is improvement percentage?

Improvement percentage tells you how much better a new result is compared to an original result, expressed as a percentage. It is one of the most common ways to measure progress in business, school, fitness, investing, and productivity.

For example, if your test score goes from 70 to 84, your result improved. But instead of just saying “it went up by 14 points,” improvement percentage tells you the size of that increase relative to where you started.

The formula

If the result is positive, you improved. If the result is negative, it means a decline.

Simple example

• Original value: 50
• New value: 65
• Change: 65 − 50 = 15
• Improvement %: (15 / 50) × 100 = 30%

So the new value is 30% better than the original value.

Step-by-step: how to calculate improvement percentage

1) Find your original value

This is your starting point: old score, old revenue, old speed, old performance metric, etc.

2) Find your new value

This is the latest result after some change or effort.

3) Subtract original from new

This gives you the raw change:

• Change = New − Original

4) Divide by the original value

This converts the raw change into a relative change compared to your starting point.

5) Multiply by 100

Now you have a percentage that is easy to compare and communicate.

Real-world use cases

Academic performance

If a student’s grade increases from 60 to 75:

Improvement % = ((75 − 60) / 60) × 100 = 25%

The student improved by 25%.

Sales growth

If monthly sales increase from $8,000 to $10,400:

Improvement % = ((10,400 − 8,000) / 8,000) × 100 = 30%

Sales improved by 30%.

Workout progress

If your bench press increases from 100 lb to 115 lb:

Improvement % = ((115 − 100) / 100) × 100 = 15%

You improved strength by 15%.

Improvement percentage vs percentage points

These are often confused:

• Percentage points are absolute differences between two percentages (e.g., from 40% to 50% is +10 percentage points).
• Improvement percentage is relative (from 40% to 50% is a 25% improvement because 10 ÷ 40 = 0.25).

Common mistakes to avoid

• Using the new value in the denominator. Always divide by the original value for improvement calculations.
• Ignoring the sign. A negative result means decline, not improvement.
• Dividing by zero. If original value is 0, percentage improvement is undefined in standard form.
• Mixing units. Make sure both values are in the same unit (dollars with dollars, seconds with seconds, etc.).

Special note about zero and negative values

If your original value is zero, you cannot use the normal formula because division by zero is undefined. In those cases, describe the change in absolute terms or use a different business rule agreed by your team.

If values can be negative, interpretation can be tricky. In many practical situations, teams use the absolute original value for clarity when discussing “improvement,” especially around error rates, debt reduction, or losses.

Quick interpretation guide

• Positive result: Improvement
• 0%: No change
• Negative result: Decline

Final takeaway

To calculate improvement percentage, compare the new value against the original value using the formula:

This gives you a clean, consistent way to measure progress in any area—from grades and finances to business metrics and personal goals. If you want a quick answer, use the calculator above.