Percent Change Calculator
Percent change measures how much a value has increased or decreased relative to its original value. The formula is: Percent Change = ((New Value − Old Value) ÷ Old Value) × 100.
How to Calculate Percent Change
- 1Identify the old (original) value and the new (current) value.
- 2Subtract the old value from the new value to get the change.
- 3Divide the change by the old value.
- 4Multiply by 100 to express as a percentage.
For example, if your Shopify store revenue went from $10,000 last month to $12,500 this month, the percent change is (($12,500 − $10,000) ÷ $10,000) × 100 = +25%. Your revenue grew by 25%.
What Is Good Growth? — Ecommerce Benchmarks
| Category | Benchmark Range |
|---|---|
| Month-over-month revenue growth | 10–20% |
| Year-over-year revenue growth | 20–50% |
| Healthy customer growth (MoM) | 5–15% |
| Traffic growth (MoM) | 5–10% |
| Conversion rate improvement (QoQ) | 5–15% |
Benchmarks vary by industry, audience, product type, and season. Use these as general guidelines.
Why Percent Change Matters for Your Shopify Store
Percent change is the universal language of business performance. Whether you’re tracking revenue, traffic, conversion rates, or ad spend, percent change tells you how things are trending relative to where they were.
Raw numbers can be misleading without percent change context. A $5,000 increase in revenue sounds great — but if you went from $100,000 to $105,000, that’s only 5% growth. If you went from $10,000 to $15,000, that’s 50% growth. Context matters.
For ecommerce businesses, tracking month-over-month and year-over-year percent changes in key metrics helps you spot trends early, set realistic growth targets, and measure the impact of changes to your marketing strategy.
BlackBox Attribution: Tired of guessing which channels are growing? BlackBox Attribution maps the customer journey from first click to purchase, so you can see which traffic sources and campaigns are actually driving more orders over time.
Common Mistakes When Calculating Percent Change
- •Dividing by the new value instead of the old value — percent change is always relative to the starting point.
- •Confusing percent change with percentage point change — going from 2% to 4% conversion rate is a 2 percentage point increase but a 100% percent change.
- •Not considering seasonal patterns when comparing periods — December revenue is naturally higher than January for most stores.
- •Using percent change on very small base numbers, which can produce misleadingly large percentages (going from 1 to 3 orders is +200% but not meaningful).
Frequently Asked Questions
How do I calculate percentage change?
Subtract the old value from the new value, divide by the old value, and multiply by 100. Formula: ((New - Old) ÷ Old) × 100. A positive result means an increase; negative means a decrease. For example, going from 200 to 250 is ((250-200) ÷ 200) × 100 = +25%.
What's the difference between percent change and percentage points?
Percent change measures relative change from a starting value. Percentage points measure the absolute difference between two percentages. If your conversion rate goes from 2% to 3%, that’s a 1 percentage point increase but a 50% percent change. Both are useful but measure different things.
How do I calculate month-over-month growth?
Use the percent change formula with last month as the old value and this month as the new value. Example: January revenue $20,000, February revenue $24,000. MoM growth = (($24,000 - $20,000) ÷ $20,000) × 100 = +20%. Track MoM growth consistently to identify trends.
How do I calculate percent change for negative numbers?
The standard formula works for negative numbers too. If you went from -$500 (loss) to $200 (profit), percent change = (($200 - (-$500)) ÷ |-$500|) × 100 = +140%. Use the absolute value of the old number as the denominator when the old value is negative.
What's a good month-over-month growth rate for ecommerce?
A healthy MoM growth rate for established ecommerce stores is 10–20%. Early-stage stores may see 30–50%+ MoM growth. Mature stores often target 5–10% steady growth. Growth rates vary by season — expect surges in Q4 and dips in January. Year-over-year comparisons are more reliable for established stores.
How do I calculate year-over-year growth?
Compare the same period across years. If January 2025 revenue was $50,000 and January 2026 revenue is $65,000, YoY growth = (($65,000 - $50,000) ÷ $50,000) × 100 = +30%. YoY comparisons eliminate seasonal bias and give a clearer picture of true business growth.
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