RSE Calculator (Relative Standard Error)

Find the relative standard error of a sample mean.

Relative standard error (%) 2.121

Standard error 1.697

Formula: RSE = (SD ÷ √n) ÷ mean × 100

Step-by-step with your numbers:

1. Values used:

2. Standard deviation = 12

3. Mean = 80

4. Sample size = 50

6. Relative standard error = 2.121%

7. Standard error = 1.697

Did we solve your problem today?

RSE expresses the standard error as a percentage of the estimate.

The math behind it

RSE = standard error ÷ mean × 100, where SE = SD ÷ √n. Lower RSE means a more reliable estimate.

SD 12, mean 80, n 50 → SE ≈ 1.70, RSE ≈ 2.1%.

When is an estimate reliable?

Many agencies treat RSE under 25–30% as usable, under 10% as good.