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How to Calculate BMI

By Jen Collins, M.S.

Body Mass Index (BMI) is an inexpensive and easy-to-perform method of estimating one’s thickness or thinness.  BMI is useful for predicting one’s future health status, as obesity can lead to a slue of health problems including: diabetes, cancer, heart disease and more. 

BMI is a number calculated from a person's weight and height. Weight in Kilograms divided by Height in Meters Squared (KG/M2).  It is meant to be used as a simple means of classifying a sedentary (physically inactive) individual’s body composition or body fatness.  BMI is not meant to be used to diagnose disease but rather to provide a way for health professionals to discuss potential health problems more objectively with their patients or clients.

BMI Calculator

BMI Norm Tables for Adults

Weight: KG
Height: CM
 
BMI:
Category:
 

<18.5 underweight
18.5 - 25 optimal weight
25 - 30 overweight
30 - 40 obese
>40 very obese

For sedentary individuals, the U.S. Centers for Desease Control


BMI is an ineffective tool for estimating body composition for athletes or physically active persons.  Active individuals have more muscle mass than sedentary individuals.  Since muscle weighs more than fat, a physically active person may have a BMI over 30 but may still have a healthy body composition. They would not be considered obese from the perspective of health risk.  The best way to assess body composition is determining percent fat and percent muscle.  Skinfold calipers can be very accurate and relatively inexpensive compared to hydrostatic or dexa-scan.

BMI is calculated differently for children and teens than it is for adults. BMI is both age-and gender-specific for children and teens. These criteria are different from those used to interpret BMI for adults which do not take into account age or gender. Children are still growing, and boys and girls develop at different rates. So, BMI for children 2 to 20 years old is determined by using a BMI chart that compares their weight and height to other boys or girls of the same age. The growth charts use a child's BMI, age, and gender to produce a BMI percentile. 
CDC Children Growth Charts >

A child or teen that is between the 85th and 95th percentile on the growth chart is considered at risk of overweight. A child or teen that is at the 95th percentile or above is considered overweight. For children, BMI is used to screen for overweight, healthy weight, or underweight. 

To Lookup Adult BMI in U.S. units, see the charts below.

BMI 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
Height
(inches)		 Body Weight (pounds)
58 91 96 100 105 110 115 119 124 129 134 138 143 148 153 158 162 167
59 94 99 104 109 114 119 124 128 133 138 143 148 153 158 163 168 173
60 97 102 107 112 118 123 128 133 138 143 148 153 158 163 168 174 179
61 100 106 111 116 122 127 132 137 143 148 153 158 164 169 174 180 185
62 104 109 115 120 126 131 136 142 147 153 158 164 169 175 180 186 191
63 107 113 118 124 130 135 141 146 152 158 163 169 175 180 186 191 197
64 110 116 122 128 134 140 145 151 157 163 169 174 180 186 192 197 204
65 114 120 126 132 138 144 150 156 162 168 174 180 186 192 198 204 210
66 118 124 130 136 142 148 155 161 167 173 179 186 192 198 204 210 216
67 121 127 134 140 146 153 159 166 172 178 185 191 198 204 211 217 223
68 125 131 138 144 151 158 164 171 177 184 190 197 203 210 216 223 230
69 128 135 142 149 155 162 169 176 182 189 196 203 209 216 223 230 236
70 132 139 146 153 160 167 174 181 188 195 202 209 216 222 229 236 243
71 136 143 150 157 165 172 179 186 193 200 208 215 222 229 236 243 250
72 140 147 154 162 169 177 184 191 199 206 213 221 228 235 242 250 258
73 144 151 159 166 174 182 189 197 204 212 219 227 235 242 250 257 265
74 148 155 163 171 179 186 194 202 210 218 225 233 241 249 256 264 272
75 152 160 168 176 184 192 200 208 216 224 232 240 248 256 264 272 279
76 156 164 172 180 189 197 205 213 221 230 238 246 254 263 271 279 287

 

MI 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
Height
(inches)		 Body Weight (pounds)
58 172 177 181 186 191 196 201 205 210 215 220 224 229 234 239 244 248 253 258
59 178 183 188 193 198 203 208 212 217 222 227 232 237 242 247 252 257 262 267
60 184 189 194 199 204 209 215 220 225 230 235 240 245 250 255 261 266 271 276
61 190 195 201 206 211 217 222 227 232 238 243 248 254 259 264 269 275 280 285
62 196 202 207 213 218 224 229 235 240 246 251 256 262 267 273 278 284 289 295
63 203 208 214 220 225 231 237 242 248 254 259 265 270 278 282 287 293 299 304
64 209 215 221 227 232 238 244 250 256 262 267 273 279 285 291 296 302 308 314
65 216 222 228 234 240 246 252 258 264 270 276 282 288 294 300 306 312 318 324
66 223 229 235 241 247 253 260 266 272 278 284 291 297 303 309 315 322 328 334
67 230 236 242 249 255 261 268 274 280 287 293 299 306 312 319 325 331 338 344
68 236 243 249 256 262 269 276 282 289 295 302 308 315 322 328 335 341 348 354
69 243 250 257 263 270 277 284 291 297 304 311 318 324 331 338 345 351 358 365
70 250 257 264 271 278 285 292 299 306 313 320 327 334 341 348 355 362 369 376
71 257 265 272 279 286 293 301 308 315 322 329 338 343 351 358 365 372 379 386
72 265 272 279 287 294 302 309 316 324 331 338 346 353 361 368 375 383 390 397
73 272 280 288 295 302 310 318 325 333 340 348 355 363 371 378 386 393 401 408
74 280 287 295 303 311 319 326 334 342 350 358 365 373 381 389 396 404 412 420
75 287 295 303 311 319 327 335 343 351 359 367 375 383 391 399 407 415 423 431
76 295 304 312 320 328 336 344 353 361 369 377 385 394 402 410 418 426 435 443