Normal Distribution

Z-Score Table: Standard Normal Probabilities

The area under the standard normal curve to the left of every z-score from −3.99 to 3.99. Use it to turn a z-score into a probability, a percentile or a p-value.

  • z from −3.99 to 3.99
  • 4 decimal places
  • Calculator included

Z-Score Table

Rows: z to one decimal · Columns: second decimal of z · Cells: area to the left of z, P(Z < z)

Negative z-scores: area to the left of z

Negative z-scores: area to the left of z
z.00.01.02.03.04.05.06.07.08.09
−3.90.00000.00000.00000.00000.00000.00000.00000.00000.00000.0000
−3.80.00010.00010.00010.00010.00010.00010.00010.00010.00010.0001
−3.70.00010.00010.00010.00010.00010.00010.00010.00010.00010.0001
−3.60.00020.00020.00010.00010.00010.00010.00010.00010.00010.0001
−3.50.00020.00020.00020.00020.00020.00020.00020.00020.00020.0002
−3.40.00030.00030.00030.00030.00030.00030.00030.00030.00030.0002
−3.30.00050.00050.00050.00040.00040.00040.00040.00040.00040.0003
−3.20.00070.00070.00060.00060.00060.00060.00060.00050.00050.0005
−3.10.00100.00090.00090.00090.00080.00080.00080.00080.00070.0007
−3.00.00130.00130.00130.00120.00120.00110.00110.00110.00100.0010
−2.90.00190.00180.00180.00170.00160.00160.00150.00150.00140.0014
−2.80.00260.00250.00240.00230.00230.00220.00210.00210.00200.0019
−2.70.00350.00340.00330.00320.00310.00300.00290.00280.00270.0026
−2.60.00470.00450.00440.00430.00410.00400.00390.00380.00370.0036
−2.50.00620.00600.00590.00570.00550.00540.00520.00510.00490.0048
−2.40.00820.00800.00780.00750.00730.00710.00690.00680.00660.0064
−2.30.01070.01040.01020.00990.00960.00940.00910.00890.00870.0084
−2.20.01390.01360.01320.01290.01250.01220.01190.01160.01130.0110
−2.10.01790.01740.01700.01660.01620.01580.01540.01500.01460.0143
−2.00.02280.02220.02170.02120.02070.02020.01970.01920.01880.0183
−1.90.02870.02810.02740.02680.02620.02560.02500.02440.02390.0233
−1.80.03590.03510.03440.03360.03290.03220.03140.03070.03010.0294
−1.70.04460.04360.04270.04180.04090.04010.03920.03840.03750.0367
−1.60.05480.05370.05260.05160.05050.04950.04850.04750.04650.0455
−1.50.06680.06550.06430.06300.06180.06060.05940.05820.05710.0559
−1.40.08080.07930.07780.07640.07490.07350.07210.07080.06940.0681
−1.30.09680.09510.09340.09180.09010.08850.08690.08530.08380.0823
−1.20.11510.11310.11120.10930.10750.10560.10380.10200.10030.0985
−1.10.13570.13350.13140.12920.12710.12510.12300.12100.11900.1170
−1.00.15870.15620.15390.15150.14920.14690.14460.14230.14010.1379
−0.90.18410.18140.17880.17620.17360.17110.16850.16600.16350.1611
−0.80.21190.20900.20610.20330.20050.19770.19490.19220.18940.1867
−0.70.24200.23890.23580.23270.22960.22660.22360.22060.21770.2148
−0.60.27430.27090.26760.26430.26110.25780.25460.25140.24830.2451
−0.50.30850.30500.30150.29810.29460.29120.28770.28430.28100.2776
−0.40.34460.34090.33720.33360.33000.32640.32280.31920.31560.3121
−0.30.38210.37830.37450.37070.36690.36320.35940.35570.35200.3483
−0.20.42070.41680.41290.40900.40520.40130.39740.39360.38970.3859
−0.10.46020.45620.45220.44830.44430.44040.43640.43250.42860.4247
−0.00.50000.49600.49200.48800.48400.48010.47610.47210.46810.4641

Positive z-scores: area to the left of z

Positive z-scores: area to the left of z
z.00.01.02.03.04.05.06.07.08.09
0.00.50000.50400.50800.51200.51600.51990.52390.52790.53190.5359
0.10.53980.54380.54780.55170.55570.55960.56360.56750.57140.5753
0.20.57930.58320.58710.59100.59480.59870.60260.60640.61030.6141
0.30.61790.62170.62550.62930.63310.63680.64060.64430.64800.6517
0.40.65540.65910.66280.66640.67000.67360.67720.68080.68440.6879
0.50.69150.69500.69850.70190.70540.70880.71230.71570.71900.7224
0.60.72570.72910.73240.73570.73890.74220.74540.74860.75170.7549
0.70.75800.76110.76420.76730.77040.77340.77640.77940.78230.7852
0.80.78810.79100.79390.79670.79950.80230.80510.80780.81060.8133
0.90.81590.81860.82120.82380.82640.82890.83150.83400.83650.8389
1.00.84130.84380.84610.84850.85080.85310.85540.85770.85990.8621
1.10.86430.86650.86860.87080.87290.87490.87700.87900.88100.8830
1.20.88490.88690.88880.89070.89250.89440.89620.89800.89970.9015
1.30.90320.90490.90660.90820.90990.91150.91310.91470.91620.9177
1.40.91920.92070.92220.92360.92510.92650.92790.92920.93060.9319
1.50.93320.93450.93570.93700.93820.93940.94060.94180.94290.9441
1.60.94520.94630.94740.94840.94950.95050.95150.95250.95350.9545
1.70.95540.95640.95730.95820.95910.95990.96080.96160.96250.9633
1.80.96410.96490.96560.96640.96710.96780.96860.96930.96990.9706
1.90.97130.97190.97260.97320.97380.97440.97500.97560.97610.9767
2.00.97720.97780.97830.97880.97930.97980.98030.98080.98120.9817
2.10.98210.98260.98300.98340.98380.98420.98460.98500.98540.9857
2.20.98610.98640.98680.98710.98750.98780.98810.98840.98870.9890
2.30.98930.98960.98980.99010.99040.99060.99090.99110.99130.9916
2.40.99180.99200.99220.99250.99270.99290.99310.99320.99340.9936
2.50.99380.99400.99410.99430.99450.99460.99480.99490.99510.9952
2.60.99530.99550.99560.99570.99590.99600.99610.99620.99630.9964
2.70.99650.99660.99670.99680.99690.99700.99710.99720.99730.9974
2.80.99740.99750.99760.99770.99770.99780.99790.99790.99800.9981
2.90.99810.99820.99820.99830.99840.99840.99850.99850.99860.9986
3.00.99870.99870.99870.99880.99880.99890.99890.99890.99900.9990
3.10.99900.99910.99910.99910.99920.99920.99920.99920.99930.9993
3.20.99930.99930.99940.99940.99940.99940.99940.99950.99950.9995
3.30.99950.99950.99950.99960.99960.99960.99960.99960.99960.9997
3.40.99970.99970.99970.99970.99970.99970.99970.99970.99970.9998
3.50.99980.99980.99980.99980.99980.99980.99980.99980.99980.9998
3.60.99980.99980.99990.99990.99990.99990.99990.99990.99990.9999
3.70.99990.99990.99990.99990.99990.99990.99990.99990.99990.9999
3.80.99990.99990.99990.99990.99990.99990.99990.99990.99990.9999
3.91.00001.00001.00001.00001.00001.00001.00001.00001.00001.0000

Tip: click any value to highlight its row and column.

How to read this table

  1. Split the z-score into its first decimal (the row) and its second decimal (the column). For z = 1.96 use row 1.9 and column .06.
  2. The cell where they meet is the area to the left of z, P(Z < z).
  3. For the area to the right, subtract the cell from 1.
  4. For a two-sided p-value, take the area beyond |z| in one tail and double it.
  5. For the area between two z-scores, subtract the smaller cell from the larger.

Worked example

A study reports a test statistic of z = 1.96. Row 1.9, column .06 gives 0.9750, the area to the left. The area to the right is 1 − 0.9750 = 0.0250, so the two-sided p-value is 2 × 0.0250 = 0.0500.

For a negative score such as z = −1.23, use the negative table: row −1.2, column .03 gives 0.1093, so about 10.9% of a normal population lies more than 1.23 standard deviations below the mean.

Click the underlined links to highlight the value in the table.

Calculator

For values between the rows and columns of the table. Results update as you type.

Formula and how the values were computed

Φ(z) = P(Z < z) = ∫−∞z (1/√(2π)) e−t²/2 dt,   with z = (x − μ) / σ

Each cell is the standard normal cumulative distribution function Φ(z), computed in double precision and rounded to four decimals. Below z = −3.99 the area is less than 0.00005, and above z = 3.99 it exceeds 0.99995.

Frequently asked questions

What is a z-score?

A z-score is the number of standard deviations a value lies from the mean: z = (x − μ) / σ. A z-score of 2 is two standard deviations above the mean.

Why does the table only give the area to the left?

The left-tail (cumulative) form works for every question: the right tail is 1 minus the cell, and areas between two values are differences of two cells. Because the normal curve is symmetric, the area to the right of z also equals the area to the left of −z.

How do I find z for a given percentile?

Search the body of the table for the area closest to your percentile and read off its row and column. For the 90th percentile the closest area is 0.8997 at z = 1.28. The calculator above gives the exact value (1.2816).

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