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T Value (Critical Value) Calculator

Select the type of probability, enter the degree of freedom and significance level to calculate t value using our t value calculator.

Is This Tool Helpful?

     

T critical value calculator is an online statistical tool that calculates the t value for one-tailed and two-tailed probability. Moreover, the critical values calculator also shows the mapped t-value in the student t distribution table.

What is t value?

T value measures the size of the difference relative to the variation in sample data. It is basically the calculated difference represented in units of standard error.

  • If t value is greater, there is evidence of a significant difference.
  • If t-value is closer to 0, there are chances of no significant difference.

How to find critical value of t?

To calculate t critical value manually (without using t calculator), follow the example below.

Example:

Calculate critical t value (one tail and two tail) for a significance level of 5% and 30 degree of freedom.

Solution:

Step 1: Identify the values.

Significance level = 5% = 5/100 = 0.05

Degree of freedom = 30

Step 2: Look for the significance level in the top row of t distribution table below (one tail) and degree of freedom (df) in the left side of the table. Get the corresponding value from table.

T critical value (one-tailed) = 1.6978

Step 3: Repeat the above step but use the two tailed t table below for two-tailed probability.

T critical value (two-tailed +/-) = 2.0428

Use our t table calculator above to quickly get t table values.

T-Distribution Table (One Tail)

The t table for one-tailed probability is given below.

DF

A = 0.1

0.05

0.025

0.01

0.005

0.001

0.0005

ta = 1.282

1.645

1.960

2.326

2.576

3.091

3.291

1

3.078

6.314

12.706

31.821

63.656

318.289

636.578

2

1.886

2.920

4.303

6.965

9.925

22.328

31.600

3

1.638

2.353

3.182

4.541

5.841

10.214

12.924

4

1.533

2.132

2.776

3.747

4.604

7.173

8.610

5

1.476

2.015

2.571

3.365

4.032

5.894

6.869

6

1.440

1.943

2.447

3.143

3.707

5.208

5.959

7

1.415

1.895

2.365

2.998

3.499

4.785

5.408

8

1.397

1.860

2.306

2.896

3.355

4.501

5.041

9

1.383

1.833

2.262

2.821

3.250

4.297

4.781

10

1.372

1.812

2.228

2.764

3.169

4.144

4.587

11

1.363

1.796

2.201

2.718

3.106

4.025

4.437

12

1.356

1.782

2.179

2.681

3.055

3.930

4.318

13

1.350

1.771

2.160

2.650

3.012

3.852

4.221

14

1.345

1.761

2.145

2.624

2.977

3.787

4.140

15

1.341

1.753

2.131

2.602

2.947

3.733

4.073

16

1.337

1.746

2.120

2.583

2.921

3.686

4.015

17

1.333

1.740

2.110

2.567

2.898

3.646

3.965

18

1.330

1.734

2.101

2.552

2.878

3.610

3.922

19

1.328

1.729

2.093

2.539

2.861

3.579

3.883

20

1.325

1.725

2.086

2.528

2.845

3.552

3.850

21

1.323

1.721

2.080

2.518

2.831

3.527

3.819

22

1.321

1.717

2.074

2.508

2.819

3.505

3.792

23

1.319

1.714

2.069

2.500

2.807

3.485

3.768

24

1.318

1.711

2.064

2.492

2.797

3.467

3.745

25

1.316

1.708

2.060

2.485

2.787

3.450

3.725

26

1.315

1.706

2.056

2.479

2.779

3.435

3.707

27

1.314

1.703

2.052

2.473

2.771

3.421

3.689

28

1.313

1.701

2.048

2.467

2.763

3.408

3.674

29

1.311

1.699

2.045

2.462

2.756

3.396

3.660

30

1.310

1.697

2.042

2.457

2.750

3.385

3.646

60

1.296

1.671

2.000

2.390

2.660

3.232

3.460

120

1.289

1.658

1.980

2.358

2.617

3.160

3.373

1000

1.282

1.646

1.962

2.330

2.581

3.098

3.300

T-Distribution Table (Two Tail)

Here is the t table for two-tailed probability.

DF

A = 0.2

0.10

0.05

0.02

0.01

0.002

0.001

ta = 1.282

1.645

1.960

2.326

2.576

3.091

3.291

1

3.078

6.314

12.706

31.821

63.656

318.289

636.578

2

1.886

2.920

4.303

6.965

9.925

22.328

31.600

3

1.638

2.353

3.182

4.541

5.841

10.214

12.924

4

1.533

2.132

2.776

3.747

4.604

7.173

8.610

5

1.476

2.015

2.571

3.365

4.032

5.894

6.869

6

1.440

1.943

2.447

3.143

3.707

5.208

5.959

7

1.415

1.895

2.365

2.998

3.499

4.785

5.408

8

1.397

1.860

2.306

2.896

3.355

4.501

5.041

9

1.383

1.833

2.262

2.821

3.250

4.297

4.781

10

1.372

1.812

2.228

2.764

3.169

4.144

4.587

11

1.363

1.796

2.201

2.718

3.106

4.025

4.437

12

1.356

1.782

2.179

2.681

3.055

3.930

4.318

13

1.350

1.771

2.160

2.650

3.012

3.852

4.221

14

1.345

1.761

2.145

2.624

2.977

3.787

4.140

15

1.341

1.753

2.131

2.602

2.947

3.733

4.073

16

1.337

1.746

2.120

2.583

2.921

3.686

4.015

17

1.333

1.740

2.110

2.567

2.898

3.646

3.965

18

1.330

1.734

2.101

2.552

2.878

3.610

3.922

19

1.328

1.729

2.093

2.539

2.861

3.579

3.883

20

1.325

1.725

2.086

2.528

2.845

3.552

3.850

21

1.323

1.721

2.080

2.518

2.831

3.527

3.819

22

1.321

1.717

2.074

2.508

2.819

3.505

3.792

23

1.319

1.714

2.069

2.500

2.807

3.485

3.768

24

1.318

1.711

2.064

2.492

2.797

3.467

3.745

25

1.316

1.708

2.060

2.485

2.787

3.450

3.725

26

1.315

1.706

2.056

2.479

2.779

3.435

3.707

27

1.314

1.703

2.052

2.473

2.771

3.421

3.689

28

1.313

1.701

2.048

2.467

2.763

3.408

3.674

29

1.311

1.699

2.045

2.462

2.756

3.396

3.660

30

1.310

1.697

2.042

2.457

2.750

3.385

3.646

60

1.296

1.671

2.000

2.390

2.660

3.232

3.460

120

1.289

1.658

1.980

2.358

2.617

3.160

3.373

1.282

1.645

1.960

2.326

2.576

3.091

3.291

 

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