Conversion Calculators
Courtesy of NWS Boston and El Paso

Text Tables

Convert
Temperature

Enter temperature in one blank to convert to the other scale.

Fahrenheit: table
Celsius:
Kelvin: table

Calculate
Wind Chill

Enter temperature and wind speed to compute wind chill.

Temperature:
    F C
Wind Speed: table
    MPH Knots
Wind Chill:
 

Calculate
Heat Index

Enter temperature and relative humidity below to calculate heat index

Temperature: table
    F C
Relative Humidity:
Heat Index: table

Wind Speed
Conversions

Enter a speed into any blank to convert to all other wind speeds.

MPH:
Km/h: table
Knots:
Meters/Second: table
 

Calculate
Relative Humidity

Enter temperature and dewpoint below to calculate relative humidity

Temperature:
    F C
Dewpoint: table
Relative Humidity:

Convert
Precipitation

Enter a depth into any blank to convert to other units .

Inches (hundredths) :
Inches: table
Millimeters:
Centimeters: table
 

Density Altitude Calculator
Enter Temp, Dewpoint, and Station Pressure*

Temperature:
  F C K
   
Dewpoint:
  F C K

Actual Station
Pressure*:

in of mercury mm of mercury
millibars (hPA)
Density Altitude Feet
Meters
* Enter actual station pressure and
NOT the Altimeter Setting!
 

Convert
Pressure

Enter a pressure in one blank to convert to the other pressures.

Millibars: table
Inches:
Millimeters: table


Celsius to Fahrenheit Conversion Table

°C     °F         °C    °F        °C   °F          °C     °F
  
 50   122.0       27   80.6        4   39.2        -19   -2.2
 49   120.2       26   78.8        3   37.4        -20   -4.0
 48   118.4       25   77.0        2   35.6        -21   -5.8
 47   116.6       24   75.2        1   33.8        -22   -7.6
 46   114.8       23   73.4        0   32.0        -23   -9.4
 45   113.0       22   71.6       -1   30.2        -24  -11.2
 44   111.2       21   69.8       -2   28.4        -25  -13.0
 43   109.4       20   68.0       -3   26.6        -26  -14.8
 42   107.6       19   66.2       -4   24.8        -27  -16.6
 41   105.8       18   64.4       -5   23.0        -28  -18.4
 40   104.0       17   62.6       -6   21.2        -29  -20.2
 39   102.2       16   60.8       -7   19.4        -30  -22.0
 38   100.4       15   59.0       -8   17.6        -31  -23.8
 37    98.6       14   57.2       -9   15.8        -32  -25.6
 36    96.8       13   55.4      -10   14.0        -33  -27.4
 35    95.0       12   53.6      -11   12.2        -34  -29.2
 34    93.2       11   51.8      -12   10.4        -35  -31.0
 33    91.4       10   50.0      -13    8.6        -36  -32.8
 32    89.6        9   48.2      -14    6.8        -37  -34.6
 31    87.8        8   46.4      -15    5.0        -38  -36.4
 30    86.0        7   44.6      -16    3.2        -39  -38.2
 29    84.2        6   42.8      -17    1.4        -40  -40.0
 28    82.4        5   41.0      -18   -0.4        -41  -41.8



Fahrenheit to Celsius Conversion Table

°F     °C         °F    °C          °F    °C           °F    °C

 125   51.6        83   28.3         41    5.0          -1  -18.3
 124   51.1        82   27.8         40    4.4          -2  -18.9
 123   50.5        81   27.2         39    3.9          -3  -19.4
 122   50.0        80   26.6         38    3.3          -4  -20.0
 121   49.4        79   26.1         37    2.8          -5  -20.5
 120   48.8        78   25.5         36    2.2          -6  -21.1
 119   48.3        77   25.0         35    1.7          -7  -21.6
 118   47.7        76   24.4         34    1.1          -8  -22.2
 117   47.2        75   23.9         33    0.6          -9  -22.8
 116   46.6        74   23.3         32    0.0         -10  -23.3
 115   46.1        73   22.8         31   -0.6         -11  -23.9
 114   45.5        72   22.2         30   -1.1         -12  -24.4
 113   45.0        71   21.6         29   -1.7         -13  -25.0
 112   44.4        70   21.1         28   -2.2         -14  -25.5
 111   43.8        69   20.5         27   -2.8         -15  -26.1
 110   43.3        68   20.0         26   -3.3         -16  -26.6
 109   42.7        67   19.4         25   -3.9         -17  -27.2
 108   42.2        66   18.9         24   -4.4         -18  -27.8
 107   41.6        65   18.3         23   -5.0         -19  -28.3
 106   41.1        64   17.8         22   -5.6         -20  -28.9
 105   40.5        63   17.2         21   -6.1         -21  -29.4
 104   40.0        62   16.7         20   -6.7         -22  -30.0
 103   39.4        61   16.1         19   -7.2         -23  -30.5
 102   38.9        60   15.5         18   -7.8         -24  -31.1
 101   38.3        59   15.0         17   -8.3         -25  -31.6
 100   37.7        58   14.4         16   -8.9         -26  -32.2
  99   37.2        57   13.9         15   -9.4         -27  -32.7
  98   36.6        56   13.3         14  -10.0         -28  -33.3
  97   36.1        55   12.8         13  -10.5         -29  -33.9
  96   35.5        54   12.2         12  -11.1         -30  -34.4
  95   35.0        53   11.7         11  -11.7         -31  -35.0
  94   34.4        52   11.1         10  -12.2         -32  -35.5
  93   33.9        51   10.5          9  -12.8         -33  -36.1
  92   33.3        50   10.0          8  -13.3         -34  -36.6
  91   32.7        49    9.4          7  -13.9         -35  -37.2
  90   32.2        48    8.9          6  -14.4         -36  -37.7
  89   31.6        47    8.3          5  -15.0         -37  -38.3
  88   31.1        46    7.8          4  -15.5         -38  -38.9
  87   30.5        45    7.2          3  -16.1         -39  -39.4
  86   30.0        44    6.7          2  -16.7         -40  -40.0
  85   29.4        43    6.1          1  -17.2         -41  -40.6
  84   28.9        42    5.6          0  -17.8         -42  -41.1



Inches of Mercury to Millibars Conversion Chart

In Hg     Mb          In Hg     Mb           In Hg     Mb           In Hg     Mb
 
 29.00   982.06        29.50    998.99        30.00   1015.92        30.50   1032.85
 29.01   982.39        29.51    999.33        30.01   1016.26        30.51   1033.19
 29.02   982.73        29.52    999.67        30.02   1016.60        30.52   1033.53
 29.03   983.07        29.53   1000.00        30.03   1016.94        30.53   1033.87
 29.04   983.41        29.54   1000.34        30.04   1017.27        30.54   1034.21
 29.05   983.75        29.55   1000.68        30.05   1017.61        30.55   1034.55
 29.06   984.09        29.56   1001.02        30.06   1017.95        30.56   1034.88
 29.07   984.43        29.57   1001.36        30.07   1018.29        30.57   1035.22
 29.08   984.77        29.58   1001.70        30.08   1018.63        30.58   1035.56
 29.09   985.10        29.59   1002.04        30.09   1018.97        30.59   1035.90
 29.10   985.44        29.60   1002.37        30.10   1019.31        30.60   1036.24
 29.11   985.78        29.61   1002.71        30.11   1019.65        30.61   1036.58
 29.12   986.12        29.62   1003.05        30.12   1019.98        30.62   1036.92
 29.13   986.46        29.63   1003.39        30.13   1020.32        30.63   1037.25
 29.14   986.80        29.64   1003.73        30.14   1020.66        30.64   1037.59
 29.15   987.14        29.65   1004.07        30.15   1021.00        30.65   1037.93
 29.16   987.47        29.66   1004.41        30.16   1021.34        30.66   1038.27
 29.17   987.81        29.67   1004.74        30.17   1021.68        30.67   1038.61
 29.18   988.15        29.68   1005.08        30.18   1022.02        30.68   1038.95
 29.19   988.49        29.69   1005.42        30.19   1022.35        30.69   1039.29
 29.20   988.83        29.70   1005.76        30.20   1022.69        30.70   1039.62
 29.21   989.17        29.71   1006.10        30.21   1023.03        30.71   1039.96
 29.22   989.51        29.72   1006.44        30.22   1023.37        30.72   1040.30
 29.23   989.84        29.73   1006.78        30.23   1023.71        30.73   1040.64
 29.24   990.18        29.74   1007.12        30.24   1024.05        30.74   1040.98
 29.25   990.52        29.75   1007.45        30.25   1024.39        30.75   1041.32
 29.26   990.86        29.76   1007.79        30.26   1024.72        30.76   1041.66
 29.27   991.20        29.77   1008.13        30.27   1025.06        30.77   1042.00
 29.28   991.54        29.78   1008.47        30.28   1025.40        30.78   1042.33
 29.29   991.88        29.79   1008.81        30.29   1025.74        30.79   1042.67
 29.30   992.22        29.80   1009.15        30.30   1026.08        30.80   1043.01
 29.31   992.55        29.81   1009.49        30.31   1026.42        30.81   1043.35
 29.32   992.89        29.82   1009.82        30.32   1026.76        30.82   1043.69
 29.33   993.23        29.83   1010.16        30.33   1027.10        30.83   1044.03
 29.34   993.57        29.84   1010.50        30.34   1027.43        30.84   1044.37
 29.35   993.91        29.85   1010.84        30.35   1027.77        30.85   1044.70
 29.36   994.25        29.86   1011.18        30.36   1028.11        30.86   1045.04
 29.37   994.59        29.87   1011.52        30.37   1028.45        30.87   1045.38
 29.38   994.92        29.88   1011.86        30.38   1028.79        30.88   1045.72
 29.39   995.26        29.89   1012.19        30.39   1029.13        30.89   1046.06
 29.40   995.60        29.90   1012.53        30.40   1029.47        30.90   1046.40
 29.41   995.94        29.91   1012.87        30.41   1029.80        30.91   1046.74
 29.42   996.28        29.92   1013.21        30.42   1030.14        30.92   1047.07
 29.43   996.62        29.93   1013.55        30.43   1030.48        30.93   1047.41
 29.44   996.96        29.94   1013.89        30.44   1030.82        30.94   1047.75
 29.45   997.29        29.95   1014.23        30.45   1031.16        30.95   1048.09
 29.46   997.63        29.96   1014.57        30.46   1031.50        30.96   1048.43
 29.47   997.97        29.97   1014.90        30.47   1031.84        30.97   1048.77
 29.48   998.31        29.98   1015.24        30.48   1032.17        30.98   1049.11
 29.49   998.65        29.99   1015.58        30.49   1032.51        30.99   1049.45



Millibars to Inches of Mercury Conversion Chart

Mb    In Hg         Mb    In Hg         Mb    In Hg         Mb    In Hg
 
 980.00  28.94       1000.00 29.53       1020.00 30.12       1040.00 30.71
 980.33  28.95       1000.33 29.54       1020.33 30.13       1040.33 30.72
 980.67  28.96       1000.67 29.55       1020.67 30.14       1040.67 30.73
 981.00  28.97       1001.00 29.56       1021.00 30.15       1041.00 30.74
 981.33  28.98       1001.33 29.57       1021.33 30.16       1041.33 30.75
 981.67  28.99       1001.67 29.58       1021.67 30.17       1041.67 30.76
 982.00  29.00       1002.00 29.59       1022.00 30.18       1042.00 30.77
 982.33  29.01       1002.33 29.60       1022.33 30.19       1042.33 30.78
 982.67  29.02       1002.67 29.61       1022.67 30.20       1042.67 30.79
 983.00  29.03       1003.00 29.62       1023.00 30.21       1043.00 30.80
 983.33  29.04       1003.33 29.63       1023.33 30.22       1043.33 30.81
 983.67  29.05       1003.67 29.64       1023.67 30.23       1043.67 30.82
 984.00  29.06       1004.00 29.65       1024.00 30.24       1044.00 30.83
 984.33  29.07       1004.33 29.66       1024.33 30.25       1044.33 30.84
 984.67  29.08       1004.67 29.67       1024.67 30.26       1044.67 30.85
 985.00  29.09       1005.00 29.68       1025.00 30.27       1045.00 30.86
 985.33  29.10       1005.33 29.69       1025.33 30.28       1045.33 30.87
 985.67  29.11       1005.67 29.70       1025.67 30.29       1045.67 30.88
 986.00  29.12       1006.00 29.71       1026.00 30.30       1046.00 30.89
 986.33  29.13       1006.33 29.72       1026.33 30.31       1046.33 30.90
 986.67  29.14       1006.67 29.73       1026.67 30.32       1046.67 30.91
 987.00  29.15       1007.00 29.74       1027.00 30.33       1047.00 30.92
 987.33  29.16       1007.33 29.75       1027.33 30.34       1047.33 30.93
 987.67  29.17       1007.67 29.76       1027.67 30.35       1047.67 30.94
 988.00  29.18       1008.00 29.77       1028.00 30.36       1048.00 30.95
 988.33  29.19       1008.33 29.78       1028.33 30.37       1048.33 30.96
 988.67  29.20       1008.67 29.79       1028.67 30.38       1048.67 30.97
 989.00  29.21       1009.00 29.80       1029.00 30.39       1049.00 30.98
 989.33  29.21       1009.33 29.81       1029.33 30.40       1049.33 30.99
 989.67  29.22       1009.67 29.82       1029.67 30.41       1049.67 31.00
 990.00  29.23       1010.00 29.83       1030.00 30.42       1050.00 31.01
 990.33  29.24       1010.33 29.84       1030.33 30.43       1050.33 31.02
 990.67  29.25       1010.67 29.84       1030.67 30.44       1050.67 31.03
 991.00  29.26       1011.00 29.85       1031.00 30.45       1051.00 31.04
 991.33  29.27       1011.33 29.86       1031.33 30.46       1051.33 31.05
 991.67  29.28       1011.67 29.87       1031.67 30.46       1051.67 31.06
 992.00  29.29       1012.00 29.88       1032.00 30.47       1052.00 31.07
 992.33  29.30       1012.33 29.89       1032.33 30.48       1052.33 31.08
 992.67  29.31       1012.67 29.90       1032.67 30.49       1052.67 31.09
 993.00  29.32       1013.00 29.91       1033.00 30.50       1053.00 31.09
 993.33  29.33       1013.33 29.92       1033.33 30.51       1053.33 31.10
 993.67  29.34       1013.67 29.93       1033.67 30.52       1053.67 31.11
 994.00  29.35       1014.00 29.94       1034.00 30.53       1054.00 31.12
 994.33  29.36       1014.33 29.95       1034.33 30.54       1054.33 31.13
 994.67  29.37       1014.67 29.96       1034.67 30.55       1054.67 31.14
 995.00  29.38       1015.00 29.97       1035.00 30.56       1055.00 31.15
 995.33  29.39       1015.33 29.98       1035.33 30.57       1055.33 31.16
 995.67  29.40       1015.67 29.99       1035.67 30.58       1055.67 31.17
 996.00  29.41       1016.00 30.00       1036.00 30.59       1056.00 31.18
 996.33  29.42       1016.33 30.01       1036.33 30.60       1056.33 31.19
 996.67  29.43       1016.67 30.02       1036.67 30.61       1056.67 31.20
 997.00  29.44       1017.00 30.03       1037.00 30.62       1057.00 31.21
 997.33  29.45       1017.33 30.04       1037.33 30.63       1057.33 31.22
 997.67  29.46       1017.67 30.05       1037.67 30.64       1057.67 31.23
 998.00  29.47       1018.00 30.06       1038.00 30.65       1058.00 31.24
 998.33  29.48       1018.33 30.07       1038.33 30.66       1058.33 31.25
 998.67  29.49       1018.67 30.08       1038.67 30.67       1058.67 31.26
 999.00  29.50       1019.00 30.09       1039.00 30.68       1059.00 31.27
 999.33  29.51       1019.33 30.10       1039.33 30.69       1059.33 31.28
 999.67  29.52       1019.67 30.11       1039.67 30.70       1059.67 31.29



MPH to Knots to Meters Per Second Conversion Chart

MPH     Kts    m/sec            MPH      Kts    m/sec
 
  1      0.9     0.4             51      44.3    22.8
  2      1.7     0.9             52      45.2    23.2
  3      2.6     1.3             53      46.1    23.7
  4      3.5     1.8             54      46.9    24.1
  5      4.3     2.2             55      47.8    24.6
  6      5.2     2.7             56      48.7    25.0
  7      6.1     3.1             57      49.5    25.5
  8      7.0     3.6             58      50.4    25.9
  9      7.8     4.0             59      51.3    26.4
 10      8.7     4.5             60      52.1    26.8
 11      9.6     4.9             61      53.0    27.3
 12     10.4     5.4             62      53.9    27.7
 13     11.3     5.8             63      54.7    28.2
 14     12.2     6.3             64      55.6    28.6
 15     13.0     6.7             65      56.5    29.1
 16     13.9     7.2             66      57.4    29.5
 17     14.8     7.6             67      58.2    30.0
 18     15.6     8.0             68      59.1    30.4
 19     16.5     8.5             69      60.0    30.8
 20     17.4     8.9             70      60.8    31.3
 21     18.2     9.4             71      61.7    31.7
 22     19.1     9.8             72      62.6    32.2
 23     20.0    10.3             73      63.4    32.6
 24     20.9    10.7             74      64.3    33.1
 25     21.7    11.2             75      65.2    33.5
 26     22.6    11.6             76      66.0    34.0
 27     23.5    12.1             77      66.9    34.4
 28     24.3    12.5             78      67.8    34.9
 29     25.2    13.0             79      68.6    35.3
 30     26.1    13.4             80      69.5    35.8
 31     26.9    13.9             81      70.4    36.2
 32     27.8    14.3             82      71.3    36.7
 33     28.7    14.8             83      72.1    37.1
 34     29.5    15.2             84      73.0    37.6
 35     30.4    15.6             85      73.9    38.0
 36     31.3    16.1             86      74.7    38.4
 37     32.2    16.5             87      75.6    38.9
 38     33.0    17.0             88      76.5    39.3
 39     33.9    17.4             89      77.3    39.8
 40     34.8    17.9             90      78.2    40.2
 41     35.6    18.3             91      79.1    40.7
 42     36.5    18.8             92      79.9    41.1
 43     37.4    19.2             93      80.8    41.6
 44     38.2    19.7             94      81.7    42.0
 45     39.1    20.1             95      82.6    42.5
 46     40.0    20.6             96      83.4    42.9
 47     40.8    21.0             97      84.3    43.4
 48     41.7    21.5             98      85.2    43.8
 49     42.6    21.9             99      86.0    44.3
 50     43.4    22.4            100      86.9    44.7



Knots to MPH to Meters Per Second Conversion Chart

Knots    MPH    m/sec          Knots      MPH     m/sec
 
  1       1.2     0.5            51       58.7     26.3
  2       2.3     1.0            52       59.8     26.8
  3       3.5     1.5            53       61.0     27.3
  4       4.6     2.1            54       62.1     27.8
  5       5.8     2.6            55       63.3     28.3
  6       6.9     3.1            56       64.4     28.8
  7       8.1     3.6            57       65.6     29.3
  8       9.2     4.1            58       66.7     29.9
  9      10.4     4.6            59       67.9     30.4
 10      11.5     5.1            60       69.0     30.9
 11      12.7     5.7            61       70.2     31.4
 12      13.8     6.2            62       71.3     31.9
 13      15.0     6.7            63       72.5     32.4
 14      16.1     7.2            64       73.7     32.9
 15      17.3     7.7            65       74.8     33.5
 16      18.4     8.2            66       76.0     34.0
 17      19.6     8.8            67       77.1     34.5
 18      20.7     9.3            68       78.3     35.0
 19      21.9     9.8            69       79.4     35.5
 20      23.0    10.3            70       80.6     36.0
 21      24.2    10.8            71       81.7     36.6
 22      25.3    11.3            72       82.9     37.1
 23      26.5    11.8            73       84.0     37.6
 24      27.6    12.4            74       85.2     38.1
 25      28.8    12.9            75       86.3     38.6
 26      29.9    13.4            76       87.5     39.1
 27      31.1    13.9            77       88.6     39.6
 28      32.2    14.4            78       89.8     40.2
 29      33.4    14.9            79       90.9     40.7
 30      34.5    15.4            80       92.1     41.2
 31      35.7    16.0            81       93.2     41.7
 32      36.8    16.5            82       94.4     42.2
 33      38.0    17.0            83       95.5     42.7
 34      39.1    17.5            84       96.7     43.2
 35      40.3    18.0            85       97.8     43.8
 36      41.4    18.5            86       99.0     44.3
 37      42.6    19.0            87      100.1     44.8
 38      43.7    19.6            88      101.3     45.3
 39      44.9    20.1            89      102.4     45.8
 40      46.0    20.6            90      103.6     46.3
 41      47.2    21.1            91      104.7     46.8
 42      48.3    21.6            92      105.9     47.4
 43      49.5    22.1            93      107.0     47.9
 44      50.6    22.7            94      108.2     48.4
 45      51.8    23.2            95      109.3     48.9
 46      52.9    23.7            96      110.5     49.4
 47      54.1    24.2            97      111.6     49.9
 48      55.2    24.7            98      112.8     50.4
 49      56.4    25.2            99      113.9     51.0
 50      57.5    25.7           100      115.1     51.5



Values in a Standard Atmosphere

Elevation       Temperature       Pressure
  (feet)        (degrees °C)         (Mb)
 
      0             15.0             1013
    500             14.0              995
  1,000             13.0              977
  1,500             12.0              959
  2,000             11.0              942
  2,500             10.0              925
  3,000              9.1              908
  3,500              8.1              891
  4,000              7.1              875
  4,500              6.1              859
  5,000              5.1              843
  5,500              4.1              827
  6,000              3.1              812
  6,500              2.1              797
  7,000              1.1              782
  7,500              0.1              767
  8,000             -0.9              752
  8,500             -1.8              738
  9,000             -2.8              724
  9,500             -3.8              710
 10,000             -4.8              697
 10,500             -5.8              683
 11,000             -6.8              670
 11,500             -7.8              657
 12,000             -8.8              644
 12,500             -9.8              632
 13,000            -10.8              619
 13,500            -11.8              607
 14,000            -12.7              595
 14,500            -13.7              583
 15,000            -14.7              572
 15,500            -15.7              560
 16,000            -16.7              549
 16,500            -17.7              538
 17,000            -18.7              527
 17,500            -19.7              516
 18,000            -20.7              506
 18,500            -21.7              495
 19,000            -22.7              485
 19,500            -23.6              475
 20,000            -24.6              465
 20,500            -25.6              456
 21,000            -26.6              446
 21,500            -27.6              437
 22,000            -28.6              428
 22,500            -29.6              419
 23,000            -30.6              410
 23,500            -31.6              401
 24,000            -32.6              392
 24,500            -33.6              384
 25,000            -34.5              376
 25,500            -35.5              368
 26,000            -36.5              360
 26,500            -37.5              352
 27,000            -38.5              344
 27,500            -39.5              336
 28,000            -40.5              329
 28,500            -41.5              322
 29,000            -42.5              315
 29,500            -43.5              307
 30,000            -44.5              301
 30,500            -45.4              294
 31,000            -46.4              287
 31,500            -47.4              281
 32,000            -48.4              274
 32,500            -49.4              268
 33,000            -50.4              262
 33,500            -51.4              256
 34,000            -52.4              250
 34,500            -53.4              244
 35,000            -54.4              238
 35,500            -55.4              232
 36,000            -56.3              225
 36,500            -57.3              219
 37,000            -58.3              213
 37,500            -59.3              207
 38,000            -60.3              200
 38,500            -61.3              194
 39,000            -62.3              188
 39,500            -63.3              182
 40,000            -64.3              176

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