T Table: Student's t Distribution Critical Values

The full Student's t table, degrees of freedom 1 to 1000 plus the normal limit, with one-tailed alpha, two-tailed alpha and confidence on every column header.

At a glance

Computes
Student's t critical values for any degrees of freedom and any probability level
You supply
Degrees of freedom, and either a cumulative probability or a significance level
Use when
You want the printable grid, or a value at a df it skips
Not for
One critical value for one alpha and one df Critical Value Calculator

This page is the grid. It lists Student's t critical values for every degrees of freedom from 1 to 100 one at a time, then out to 1000 and the normal limit, across eleven probability columns. For one alpha and one df, use the critical value calculator. Both pages use the same quantile function, so their answers cannot disagree.

Decimals from a Welch correction are accepted. Type inf for the normal limit.

Read using the probability framing below.

Probability framing
Chart shading

Type degrees of freedom and a probability to highlight a cell.

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Probability density; Student t, df 10

−5052.228139Student t, df 10

Most-used t values

Positive t critical values for common two-sided confidence levels.
Confidencedf 10df 20df 30df 60df 120Normal
90%1.81251.72471.69731.67061.65771.6449
95%2.22812.08602.04232.00031.97991.9600
99%3.16932.84532.75002.66032.61742.5758

The new column is inserted in cumulative-probability order.

Student's t critical values

Body values are t such that P(T <= t) equals the column's cumulative probability. Degrees of freedom run down the left.
df0.75one-tailed 0.25two-tailed 0.550% confidence0.8one-tailed 0.2two-tailed 0.460% confidence0.85one-tailed 0.15two-tailed 0.370% confidence0.9one-tailed 0.1two-tailed 0.280% confidence0.95one-tailed 0.05two-tailed 0.190% confidence0.975one-tailed 0.025two-tailed 0.0595% confidence0.99one-tailed 0.01two-tailed 0.0298% confidence0.995one-tailed 0.005two-tailed 0.0199% confidence0.9975one-tailed 0.0025two-tailed 0.00599.5% confidence0.999one-tailed 0.001two-tailed 0.00299.8% confidence0.9995one-tailed 0.0005two-tailed 0.00199.9% confidence
11.00001.37641.96263.07776.313812.706231.820563.6567127.321318.309636.619
20.81651.06071.38621.88562.92004.30276.96469.924814.089022.327131.5991
30.76490.97851.24981.63772.35343.18244.54075.84097.453310.214512.9240
40.74070.94101.18961.53322.13182.77643.74694.60415.59767.17328.6103
50.72670.91951.15581.47592.01502.57063.36494.03214.77335.89346.8688
60.71760.90571.13421.43981.94322.44693.14273.70744.31685.20765.9588
70.71110.89601.11921.41491.89462.36462.99803.49954.02934.78535.4079
80.70640.88891.10811.39681.85952.30602.89653.35543.83254.50085.0413
90.70270.88341.09971.38301.83312.26222.82143.24983.68974.29684.7809
100.69980.87911.09311.37221.81252.22812.76383.16933.58144.14374.5869
110.69740.87551.08771.36341.79592.20102.71813.10583.49664.02474.4370
120.69550.87261.08321.35621.78232.17882.68103.05453.42843.92964.3178
130.69380.87021.07951.35021.77092.16042.65033.01233.37253.85204.2208
140.69240.86811.07631.34501.76132.14482.62452.97683.32573.78744.1405
150.69120.86621.07351.34061.75312.13142.60252.94673.28603.73284.0728
160.69010.86471.07111.33681.74592.11992.58352.92083.25203.68624.0150
170.68920.86331.06901.33341.73962.10982.56692.89823.22243.64583.9651
180.68840.86201.06721.33041.73412.10092.55242.87843.19663.61053.9216
190.68760.86101.06551.32771.72912.09302.53952.86093.17373.57943.8834
200.68700.86001.06401.32531.72472.08602.52802.84533.15343.55183.8495
210.68640.85911.06271.32321.72072.07962.51762.83143.13523.52723.8193
220.68580.85831.06141.32121.71712.07392.50832.81883.11883.50503.7921
230.68530.85751.06031.31951.71392.06872.49992.80733.10403.48503.7676
240.68480.85691.05931.31781.71092.06392.49222.79693.09053.46683.7454
250.68440.85621.05841.31631.70812.05952.48512.78743.07823.45023.7251
260.68400.85571.05751.31501.70562.05552.47862.77873.06693.43503.7066
270.68370.85511.05671.31371.70332.05182.47272.77073.05653.42103.6896
280.68340.85461.05601.31251.70112.04842.46712.76333.04693.40823.6739
290.68300.85421.05531.31141.69912.04522.46202.75643.03803.39623.6594
300.68280.85381.05471.31041.69732.04232.45732.75003.02983.38523.6460
310.68250.85341.05411.30951.69552.03952.45282.74403.02213.37493.6335
320.68220.85301.05351.30861.69392.03692.44872.73853.01493.36533.6218
330.68200.85261.05301.30771.69242.03452.44482.73333.00823.35633.6109
340.68180.85231.05251.30701.69092.03222.44112.72843.00203.34793.6007
350.68160.85201.05201.30621.68962.03012.43772.72382.99603.34003.5911
360.68140.85171.05161.30551.68832.02812.43452.71952.99053.33263.5821
370.68120.85141.05121.30491.68712.02622.43142.71542.98523.32563.5737
380.68100.85121.05081.30421.68602.02442.42862.71162.98033.31903.5657
390.68080.85091.05041.30361.68492.02272.42582.70792.97563.31283.5581
400.68070.85071.05001.30311.68392.02112.42332.70452.97123.30693.5510
410.68050.85051.04971.30251.68292.01952.42082.70122.96703.30133.5442
420.68040.85031.04941.30201.68202.01812.41852.69812.96303.29603.5377
430.68020.85011.04911.30161.68112.01672.41632.69512.95923.29093.5316
440.68010.84991.04881.30111.68022.01542.41412.69232.95553.28613.5258
450.68000.84971.04851.30061.67942.01412.41212.68962.95213.28153.5203
460.67990.84951.04831.30021.67872.01292.41022.68702.94883.27713.5150
470.67970.84931.04801.29981.67792.01172.40832.68462.94563.27293.5099
480.67960.84921.04781.29941.67722.01062.40662.68222.94263.26893.5051
490.67950.84901.04751.29911.67662.00962.40492.68002.93973.26513.5004
500.67940.84891.04731.29871.67592.00862.40332.67782.93703.26143.4960
510.67930.84871.04711.29841.67532.00762.40172.67572.93433.25793.4918
520.67920.84861.04691.29801.67472.00662.40022.67372.93183.25453.4877
530.67910.84851.04671.29771.67412.00572.39882.67182.92933.25133.4838
540.67910.84831.04651.29741.67362.00492.39742.67002.92703.24813.4800
550.67900.84821.04631.29711.67302.00402.39612.66822.92473.24513.4764
560.67890.84811.04611.29691.67252.00322.39482.66652.92253.24233.4729
570.67880.84801.04591.29661.67202.00252.39362.66492.92043.23953.4696
580.67870.84791.04581.29631.67162.00172.39242.66332.91843.23683.4663
590.67870.84781.04561.29611.67112.00102.39122.66182.91643.23423.4632
600.67860.84771.04551.29581.67062.00032.39012.66032.91463.23173.4602
610.67850.84761.04531.29561.67021.99962.38902.65892.91273.22933.4573
620.67850.84751.04521.29541.66981.99902.38802.65752.91103.22703.4545
630.67840.84741.04501.29511.66941.99832.38702.65612.90933.22473.4518
640.67830.84731.04491.29491.66901.99772.38602.65492.90763.22253.4491
650.67830.84721.04481.29471.66861.99712.38512.65362.90603.22043.4466
660.67820.84711.04461.29451.66831.99662.38422.65242.90453.21843.4441
670.67820.84701.04451.29431.66791.99602.38332.65122.90303.21643.4417
680.67810.84691.04441.29411.66761.99552.38242.65012.90153.21453.4394
690.67810.84691.04431.29391.66721.99492.38162.64902.90013.21263.4372
700.67800.84681.04421.29381.66691.99442.38082.64792.89873.21083.4350
710.67800.84671.04411.29361.66661.99392.38002.64692.89743.20903.4329
720.67790.84661.04401.29341.66631.99352.37932.64592.89613.20733.4308
730.67790.84661.04381.29331.66601.99302.37852.64492.89493.20573.4289
740.67780.84651.04371.29311.66571.99252.37782.64392.89363.20413.4269
750.67780.84641.04361.29291.66541.99212.37712.64302.89243.20253.4250
760.67770.84641.04361.29281.66521.99172.37642.64212.89133.20103.4232
770.67770.84631.04351.29261.66491.99132.37582.64122.89023.19953.4214
780.67760.84631.04341.29251.66461.99082.37512.64032.88913.19803.4197
790.67760.84621.04331.29241.66441.99052.37452.63952.88803.19663.4180
800.67760.84611.04321.29221.66411.99012.37392.63872.88703.19533.4163
810.67750.84611.04311.29211.66391.98972.37332.63792.88603.19393.4147
820.67750.84601.04301.29201.66361.98932.37272.63712.88503.19263.4132
830.67750.84601.04291.29181.66341.98902.37212.63642.88403.19133.4116
840.67740.84591.04291.29171.66321.98862.37162.63562.88313.19013.4102
850.67740.84591.04281.29161.66301.98832.37102.63492.88223.18893.4087
860.67740.84581.04271.29151.66281.98792.37052.63422.88133.18773.4073
870.67730.84581.04261.29141.66261.98762.37002.63352.88043.18663.4059
880.67730.84571.04261.29121.66241.98732.36952.63292.87953.18543.4045
890.67730.84571.04251.29111.66221.98702.36902.63222.87873.18433.4032
900.67720.84561.04241.29101.66201.98672.36852.63162.87793.18333.4019
910.67720.84561.04241.29091.66181.98642.36802.63092.87713.18223.4007
920.67720.84551.04231.29081.66161.98612.36762.63032.87633.18123.3994
930.67710.84551.04221.29071.66141.98582.36712.62972.87553.18023.3982
940.67710.84551.04221.29061.66121.98552.36672.62912.87483.17923.3971
950.67710.84541.04211.29051.66111.98532.36622.62862.87413.17823.3959
960.67710.84541.04211.29041.66091.98502.36582.62802.87343.17733.3948
970.67700.84531.04201.29031.66071.98472.36542.62752.87273.17643.3937
980.67700.84531.04191.29021.66061.98452.36502.62692.87203.17553.3926
990.67700.84531.04191.29021.66041.98422.36462.62642.87133.17463.3915
1000.67700.84521.04181.29011.66021.98402.36422.62592.87073.17373.3905
1100.67670.84491.04131.28931.65881.98182.36072.62132.86483.16603.3812
1200.67650.84461.04091.28861.65771.97992.35782.61742.85993.15953.3735
1500.67610.84401.04001.28721.65511.97592.35152.60902.84923.14553.3566
2000.67570.84341.03911.28581.65251.97192.34512.60062.83853.13153.3398
2500.67550.84311.03861.28491.65101.96952.34142.59562.83223.12323.3299
3000.67530.84281.03821.28441.64991.96792.33882.59232.82793.11763.3233
4000.67510.84251.03781.28371.64871.96592.33572.58822.82273.11073.3150
5000.67500.84231.03751.28321.64791.96472.33382.58572.81953.10663.3101
10000.67470.84201.03701.28241.64641.96232.33012.58082.81333.09843.3003
0.67450.84161.03641.28161.64491.96002.32632.57582.80703.09023.2905
Reverse lookup: statistic to p-value

How to read this table

Find your degrees of freedom down the left, then choose the column whose one-tailed or two-tailed alpha matches your test. The cell is the positive critical value. The lower-tail value is the same number with a minus sign.

Degrees of freedom that are not on the grid

Interpolation is unnecessary here. Type the degrees of freedom you actually have into the lookup field and the critical value is computed for that df. The printed grid is bounded at 110 rows; values outside it are computed rather than silently approximated.

P(T <= t) = p; t = inverseT(p, df) How?

How this is calculated

Finite rows use the shared Student t quantile. The infinity row uses the standard normal limit. Grid cells show magnitude-adjusted published precision, while CSV and cell copy retain ten significant figures.

Formula: P(T <= t) = p; t = inverseT(p, df)

Sources

  1. Critical Values of the Student's t Distribution (e-Handbook 1.3.6.7.2). NIST/SEMATECH. Retrieved .
  2. Student's t-distribution, table of selected values. Wikipedia. Retrieved .
  3. Numerical Recipes section 6.4, incomplete beta function. Press, Teukolsky, Vetterling and Flannery. Retrieved .
  4. An algorithm for computing the inverse normal cumulative distribution function. Peter J. Acklam. Retrieved .