Free calculator
Year-over-year (YoY) growth calculator
Compare one metric in two periods: the prior-year value (same calendar slice—month, quarter, or year) and the current value. We show YoY growth % and absolute change. This is classic year-over-year math—not CAGR over several years (use the CAGR calculator for PV/FV/time) and not month-over-month—see methodology.
When to use this calculator
Fast same-metric checks for year-over-year reporting—before you wire formulas into a full model.
- Compare revenue, orders, or active users this year vs the same window last year for a headline growth rate.
- Sanity-check a board slide or investor update line against the (current − prior) ÷ prior definition.
- Copy the Sheets/Excel pattern into a row so your workbook matches this page’s YoY %.
- Jump to the ROI tool when you need CAGR from two totals and a holding period, or compound interest for contributions over time.
Year-over-year (YoY) compares one metric in two aligned periods one year apart—for example Q1 this year vs Q1 last year, or full-year vs full-year.
YoY growth %
YoY % = (current ÷ prior − 1) × 100, same as ((current − prior) ÷ prior) × 100. Absolute change = current − prior.
Why prior cannot be zero
Dividing by prior needs a non-zero base. With prior = 0, the percent change is undefined—pick another baseline or KPI.
What we do not model
CAGR over multiple years, IRR, MoM/QoQ slices, seasonality adjustments, and inflation-adjusted “real” YoY are out of scope for this two-number tool—see links below.
Keep definitions aligned with your finance policy; this page is a transparent teaching calculator. For CAGR from invested vs returned and an optional period, open the ROI calculator. For generic percent-of and percent-change drills, use the percentage calculator. For balances with contributions and compounding, use the compound interest calculator.
Google Sheets & Excel
Put prior in A2 and current in B2 (same units). English US/UK function names below—use Formulas → Insert function for other Excel language packs.
=(B2-A2)/A2Format as Percent, or multiply by 100 if you prefer a numeric ratio without percent formatting.
=B2/A2-1Equivalent to (B2−A2)/A2 when A2 ≠ 0.
Frequently asked questions
What is year-over-year (YoY) growth?
YoY compares the same metric in two periods separated by about one year—for example this January vs last January. On this page it is one prior value and one current value.
What is the YoY growth formula here?
YoY % = (current ÷ prior − 1) × 100. Absolute change = current − prior. Use the same units and same definition of the metric for both boxes.
Why is there no YoY % when the prior value is zero?
The formula divides by prior. When prior is zero, that ratio is undefined, so we only show an error—not a made-up percent.
What does YoY mean if the prior value is negative?
The math still computes (current ÷ prior − 1) × 100, but negative bases flip how a percent reads vs intuition (for example “less negative” can look like “down”). Use the result as a sanity check, not a story by itself.
How do I get growth over three or five years?
This page is one year vs the prior year. For a smoothed rate over several years from two endpoints, use CAGR on the ROI calculator with your span. For year-by-year chain growth, build a small table in a sheet.
Is this month-over-month (MoM) or quarter-over-quarter?
No—inputs are only prior vs current for your chosen periods. For MoM or QoQ, use the same percent-change math with the right two cells, or the percentage calculator for a generic A → B change.
How is this different from the percentage calculator?
The math for percent change is the same family. This page frames the pair as year-over-year (same metric, prior year base) so reporting users land on the right definition—the percentage tool stays broader.
How do I match this in Google Sheets or Excel?
Put prior in A2 and current in B2. YoY decimal: =(B2-A2)/A2 or =B2/A2-1, then format as percent. See the copy cards on this page.
Does this adjust for inflation (“real YoY”)?
No. Both values are nominal as you type them. For purchasing power with an assumed annual rate, see the inflation calculator—still an illustration, not an official index.
Is this financial, tax, or accounting advice?
No. It is a free educational calculator—not a substitute for professional advice when filings, contracts, or investments are involved.