GlenCalc

Normal distribution calculator

Enter the mean and standard deviation, and the two values that mark the range you care about.

Your answer

Probability between68.269 %
Probability below the lower value15.866 %
Probability above the upper value15.866 %
z-score of the lower value-1
z-score of the upper value1
The bell curve
Show the numbers
The bell curve
ValueDensity
400
430
460
490.0001
520.0002
550.0003
580.0005
610.0009
640.0015
670.0024
700.0036
730.0053
760.0074
790.01
820.0129
850.0161
880.0193
910.0222
940.0246
970.0261
1000.0266
1030.0261
1060.0246
1090.0222
1120.0193
1150.0161
1180.0129
1210.01
1240.0074
1270.0053
1300.0036
1330.0024
1360.0015
1390.0009
1420.0005
1450.0003
1480.0002
1510.0001
1540
1570
1600

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Step-by-step solution

Updated as you change the numbers.

  1. z = (value − 100) ÷ 15.
  2. Probability between = area left of the upper z − area left of the lower z.

Method and assumptions

Uses the standard normal cumulative distribution. About 68% of values lie within one standard deviation of the mean, 95% within two and 99.7% within three.

Questions

What share of values is within one standard deviation?

About 68.27%.

Sources

Method and figures checked on October 31, 2026. Every worked answer on this page is covered by an automated test. Found a mistake? Tell us.

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