Critical values of r by degrees of freedom and significance level.
The critical values of the Pearson correlation coefficient (r) tell you how large a correlation must be, for a given sample size, to be statistically significant. Find the row for your degrees of freedom (df = n − 2, where n is the number of paired observations) and the column for your two-tailed significance level α. If your observed |r| is greater than or equal to the table value, the correlation is significant at that level.
Columns are two-tailed α levels. For a one-tailed test, the same value corresponds to half the α (e.g. the α = 0.05 two-tailed column is the α = 0.025 one-tailed critical value).
Example: You collect n = 12 paired observations, so df = 10. The two-tailed critical value at α = 0.05 is 0.5760. If your computed correlation is r = 0.64, then 0.64 > 0.576, so the correlation is statistically significant (p < 0.05).
| df (n−2) | α=0.10 | α=0.05 | α=0.02 | α=0.01 |
|---|---|---|---|---|
| 1 | 0.9877 | 0.9969 | 0.9995 | 0.9999 |
| 2 | 0.9000 | 0.9500 | 0.9800 | 0.9900 |
| 3 | 0.8054 | 0.8783 | 0.9343 | 0.9587 |
| 4 | 0.7293 | 0.8114 | 0.8822 | 0.9172 |
| 5 | 0.6694 | 0.7545 | 0.8329 | 0.8745 |
| 6 | 0.6215 | 0.7067 | 0.7887 | 0.8343 |
| 7 | 0.5822 | 0.6664 | 0.7498 | 0.7977 |
| 8 | 0.5494 | 0.6319 | 0.7155 | 0.7646 |
| 9 | 0.5214 | 0.6021 | 0.6851 | 0.7348 |
| 10 | 0.4973 | 0.5760 | 0.6581 | 0.7079 |
| 11 | 0.4762 | 0.5529 | 0.6339 | 0.6835 |
| 12 | 0.4575 | 0.5324 | 0.6120 | 0.6614 |
| 13 | 0.4409 | 0.5140 | 0.5923 | 0.6411 |
| 14 | 0.4259 | 0.4973 | 0.5742 | 0.6226 |
| 15 | 0.4124 | 0.4821 | 0.5577 | 0.6055 |
| 16 | 0.4000 | 0.4683 | 0.5425 | 0.5897 |
| 17 | 0.3887 | 0.4555 | 0.5285 | 0.5751 |
| 18 | 0.3783 | 0.4438 | 0.5155 | 0.5614 |
| 19 | 0.3687 | 0.4329 | 0.5034 | 0.5487 |
| 20 | 0.3598 | 0.4227 | 0.4921 | 0.5368 |
| 25 | 0.3233 | 0.3809 | 0.4451 | 0.4869 |
| 30 | 0.2960 | 0.3494 | 0.4093 | 0.4487 |
| 35 | 0.2746 | 0.3246 | 0.3810 | 0.4182 |
| 40 | 0.2573 | 0.3044 | 0.3578 | 0.3932 |
| 45 | 0.2429 | 0.2876 | 0.3384 | 0.3721 |
| 50 | 0.2306 | 0.2732 | 0.3218 | 0.3542 |
| 60 | 0.2108 | 0.2500 | 0.2948 | 0.3248 |
| 70 | 0.1954 | 0.2319 | 0.2737 | 0.3017 |
| 80 | 0.1829 | 0.2172 | 0.2565 | 0.2830 |
| 90 | 0.1726 | 0.2050 | 0.2422 | 0.2673 |
| 100 | 0.1638 | 0.1946 | 0.2301 | 0.2540 |
Computed with SciPy: rcrit = tcrit / √(df + tcrit²), where tcrit = t.ppf(1−α/2, df). Values match standard published correlation tables. See the methodology page.
Use it to check significance of a Pearson correlation by hand, or to sanity-check software output. Remember that significance is not the same as importance — a small but significant r can explain very little variance. Run the full test, including the exact p-value and r², with the correlation calculator, and read correlation vs causation before drawing conclusions.