It is sometimes useful to know the vapour pressure of water. Below is a list of high-precision values. This uses the Wagner & Pruss equation (1993 J Phys Chem Ref Data 22, pp 783-787).
The table uses the modern single-fixed-point thermodynamic temperature scale in which the triple point of water is 273.16 K exactly, and celsius degrees are defined as K - 273.15. The boiling point of water is no longer a fixed point. Referring to the table, the "normal boiling point" (i.e. at 1 standard atmosphere pressure = 101325 Pa) is 99.9743°C, while the IUPAC standard boiling point (i.e. at 100 kPa) is 99.6059°C.
temp °C | pressure kPa |
---|---|
0 | 0.61121 |
1 | 0.65708 |
2 | 0.70597 |
3 | 0.75805 |
4 | 0.81351 |
5 | 0.87253 |
6 | 0.93530 |
7 | 1.00203 |
8 | 1.07292 |
9 | 1.14821 |
10 | 1.22811 |
11 | 1.31288 |
12 | 1.40275 |
13 | 1.49799 |
14 | 1.59887 |
15 | 1.70568 |
16 | 1.81870 |
17 | 1.93824 |
18 | 2.06461 |
19 | 2.19815 |
20 | 2.33919 |
21 | 2.48810 |
22 | 2.64522 |
23 | 2.81096 |
24 | 2.98569 |
25 | 3.16982 |
26 | 3.36379 |
27 | 3.56802 |
28 | 3.78298 |
29 | 4.00911 |
30 | 4.24692 |
31 | 4.49690 |
32 | 4.75956 |
33 | 5.03543 |
34 | 5.32508 |
35 | 5.62906 |
36 | 5.94796 |
37 | 6.28238 |
38 | 6.63295 |
39 | 7.00031 |
40 | 7.38511 |
41 | 7.78804 |
42 | 8.20980 |
43 | 8.65110 |
44 | 9.11270 |
45 | 9.59534 |
46 | 10.09981 |
47 | 10.62693 |
48 | 11.17751 |
49 | 11.75240 |
50 | 12.35248 |
51 | 12.97864 |
52 | 13.63180 |
53 | 14.31291 |
54 | 15.02293 |
55 | 15.76284 |
56 | 16.53368 |
57 | 17.33647 |
58 | 18.17228 |
59 | 19.04222 |
60 | 19.94738 |
61 | 20.88893 |
62 | 21.86802 |
63 | 22.88587 |
64 | 23.94368 |
65 | 25.04273 |
66 | 26.18428 |
67 | 27.36965 |
68 | 28.60018 |
69 | 29.87723 |
70 | 31.20220 |
71 | 32.57651 |
72 | 34.00162 |
73 | 35.47901 |
74 | 37.01020 |
75 | 38.59673 |
76 | 40.24018 |
77 | 41.94216 |
78 | 43.70430 |
79 | 45.52827 |
80 | 47.41578 |
81 | 49.36856 |
82 | 51.38837 |
83 | 53.47701 |
84 | 55.63632 |
85 | 57.86815 |
86 | 60.17439 |
87 | 62.55699 |
88 | 65.01790 |
89 | 67.55912 |
90 | 70.18268 |
91 | 72.89064 |
92 | 75.68510 |
93 | 78.56819 |
94 | 81.54209 |
95 | 84.60899 |
96 | 87.77112 |
97 | 91.03076 |
98 | 94.39022 |
99 | 97.85184 |
100 | 101.4180 |
101 | 105.0911 |
102 | 108.8736 |
103 | 112.7680 |
104 | 116.7767 |
105 | 120.9025 |
106 | 125.1477 |
107 | 129.5152 |
108 | 134.0074 |
109 | 138.6273 |
110 | 143.3773 |
111 | 148.2605 |
112 | 153.2795 |
113 | 158.4372 |
114 | 163.7364 |
115 | 169.1802 |
116 | 174.7714 |
117 | 180.5131 |
118 | 186.4083 |
119 | 192.4600 |
120 | 198.6714 |
121 | 205.0456 |
122 | 211.5857 |
123 | 218.2951 |
124 | 225.1769 |
125 | 232.2344 |
126 | 239.4709 |
127 | 246.8899 |
128 | 254.4947 |
129 | 262.2887 |
130 | 270.2754 |
131 | 278.4584 |
132 | 286.8412 |
133 | 295.4274 |
134 | 304.2205 |
135 | 313.2243 |
136 | 322.4424 |
137 | 331.8786 |
138 | 341.5366 |
139 | 351.4203 |
140 | 361.5335 |
141 | 371.8801 |
142 | 382.4639 |
143 | 393.2890 |
144 | 404.3593 |
145 | 415.6788 |
146 | 427.2517 |
147 | 439.0819 |
148 | 451.1738 |
149 | 463.5313 |
150 | 476.1587 |
151 | 489.0603 |
152 | 502.2404 |
153 | 515.7032 |
154 | 529.4531 |
155 | 543.4945 |
156 | 557.8318 |
157 | 572.4694 |
158 | 587.4120 |
159 | 602.6639 |
160 | 618.2297 |
161 | 634.1141 |
162 | 650.3217 |
163 | 666.8572 |
164 | 683.7251 |
165 | 700.9304 |
166 | 718.4777 |
167 | 736.3720 |
168 | 754.6179 |
169 | 773.2204 |
170 | 792.1844 |
171 | 811.5148 |
172 | 831.2167 |
173 | 851.2950 |
174 | 871.7547 |
175 | 892.6011 |
176 | 913.8391 |
177 | 935.4739 |
178 | 957.5108 |
179 | 979.9549 |
180 | 1002.811 |
181 | 1026.086 |
182 | 1049.783 |
183 | 1073.909 |
184 | 1098.469 |
185 | 1123.467 |
186 | 1148.911 |
187 | 1174.805 |
188 | 1201.154 |
189 | 1227.964 |
190 | 1255.242 |
191 | 1282.992 |
192 | 1311.219 |
193 | 1339.931 |
194 | 1369.132 |
195 | 1398.828 |
196 | 1429.025 |
197 | 1459.729 |
198 | 1490.945 |
199 | 1522.680 |
200 | 1554.939 |
201 | 1587.729 |
202 | 1621.055 |
203 | 1654.923 |
204 | 1689.339 |
205 | 1724.310 |
206 | 1759.841 |
207 | 1795.938 |
208 | 1832.609 |
209 | 1869.858 |
210 | 1907.692 |
211 | 1946.118 |
212 | 1985.142 |
213 | 2024.769 |
214 | 2065.007 |
215 | 2105.861 |
216 | 2147.339 |
217 | 2189.446 |
218 | 2232.189 |
219 | 2275.575 |
220 | 2319.610 |
221 | 2364.300 |
222 | 2409.652 |
223 | 2455.674 |
224 | 2502.371 |
225 | 2549.750 |
226 | 2597.818 |
227 | 2646.582 |
228 | 2696.048 |
229 | 2746.224 |
230 | 2797.116 |
231 | 2848.730 |
232 | 2901.075 |
233 | 2954.157 |
234 | 3007.983 |
235 | 3062.560 |
236 | 3117.894 |
237 | 3173.994 |
238 | 3230.866 |
239 | 3288.518 |
240 | 3346.956 |
241 | 3406.188 |
242 | 3466.220 |
243 | 3527.062 |
244 | 3588.719 |
245 | 3651.199 |
246 | 3714.509 |
247 | 3778.657 |
248 | 3843.651 |
249 | 3909.497 |
250 | 3976.204 |
251 | 4043.779 |
252 | 4112.230 |
253 | 4181.564 |
254 | 4251.789 |
255 | 4322.912 |
256 | 4394.942 |
257 | 4467.886 |
258 | 4541.753 |
259 | 4616.550 |
260 | 4692.284 |
261 | 4768.965 |
262 | 4846.599 |
263 | 4925.196 |
264 | 5004.763 |
265 | 5085.308 |
266 | 5166.840 |
267 | 5249.367 |
268 | 5332.896 |
269 | 5417.437 |
270 | 5502.998 |
271 | 5589.587 |
272 | 5677.213 |
273 | 5765.884 |
274 | 5855.609 |
275 | 5946.397 |
276 | 6038.256 |
277 | 6131.194 |
278 | 6225.222 |
279 | 6320.346 |
280 | 6416.578 |
281 | 6513.925 |
282 | 6612.396 |
283 | 6712.001 |
284 | 6812.749 |
285 | 6914.649 |
286 | 7017.710 |
287 | 7121.941 |
288 | 7227.353 |
289 | 7333.954 |
290 | 7441.755 |
291 | 7550.764 |
292 | 7660.991 |
293 | 7772.447 |
294 | 7885.141 |
295 | 7999.083 |
296 | 8114.283 |
297 | 8230.751 |
298 | 8348.498 |
299 | 8467.533 |
300 | 8587.867 |
301 | 8709.511 |
302 | 8832.475 |
303 | 8956.770 |
304 | 9082.406 |
305 | 9209.395 |
306 | 9337.747 |
307 | 9467.474 |
308 | 9598.586 |
309 | 9731.096 |
310 | 9865.014 |
311 | 10000.35 |
312 | 10137.12 |
313 | 10275.34 |
314 | 10415.00 |
315 | 10556.14 |
316 | 10698.76 |
317 | 10842.87 |
318 | 10988.48 |
319 | 11135.62 |
320 | 11284.28 |
321 | 11434.49 |
322 | 11586.25 |
323 | 11739.58 |
324 | 11894.50 |
325 | 12051.02 |
326 | 12209.15 |
327 | 12368.90 |
328 | 12530.30 |
329 | 12693.35 |
330 | 12858.08 |
331 | 13024.49 |
332 | 13192.60 |
333 | 13362.43 |
334 | 13533.99 |
335 | 13707.30 |
336 | 13882.38 |
337 | 14059.24 |
338 | 14237.91 |
339 | 14418.39 |
340 | 14600.71 |
341 | 14784.89 |
342 | 14970.94 |
343 | 15158.89 |
344 | 15348.75 |
345 | 15540.55 |
346 | 15734.31 |
347 | 15930.04 |
348 | 16127.77 |
349 | 16327.53 |
350 | 16529.34 |
351 | 16733.22 |
352 | 16939.20 |
353 | 17147.30 |
354 | 17357.56 |
355 | 17569.99 |
356 | 17784.64 |
357 | 18001.53 |
358 | 18220.70 |
359 | 18442.17 |
360 | 18666.00 |
361 | 18892.21 |
362 | 19120.85 |
363 | 19351.96 |
364 | 19585.59 |
365 | 19821.79 |
366 | 20060.64 |
367 | 20302.18 |
368 | 20546.49 |
369 | 20793.67 |
370 | 21043.82 |
371 | 21297.08 |
372 | 21553.65 |
373 | 21813.82 |