Paired change
Before vs. after
Calculate a result to visualize how each pair changed.
Paired T-Test Calculator
Compare two related measurements and get the t statistic, p-value, confidence interval, effect size, and report-ready interpretation.
Step 1
Enter your paired data
Difference = After − Before
Paste two columns from Excel or Google Sheets directly into any cell.
| Pair | Before | After | Difference | Remove |
|---|
0 complete pairs
Results
Paired t-test results
t statistic
—
df
—
p-value
—
Decision
Ready
Summary statistics
Complete pairs—
Mean difference—
Before mean—
After mean—
SD of differences—
Standard error—
95% CI—
Cohen's dz—
Interpretation
Enter at least two complete pairs, then calculate to see the statistical conclusion.
Report-ready
APA-style result
Your APA-style result will appear here after calculation.
Paired differences
| Pair | Before | After | After − Before |
|---|---|---|---|
| No calculated pairs yet. | |||
How the paired t test is calculated
t = d̄ / (sd / √n)
The calculator first computes each paired difference as After − Before. It then tests whether the population mean of those differences is zero.
When to use a paired samples t test
Use it when each value in the first measurement has a specific partner in the second measurement, such as the same subjects measured before and after an intervention or matched observations under two conditions.