Target Weight Calculator

Exactly three years ago, when I began training/exercising more regularly, my weight had peaked at 12lbs above my ideal weight.  I started out with 29.5% body fat,  and now 3 years and 22lbs later, my body fat is between 20-21%.  🙂

They say that when you aim to lose weight, you should monitor not only your weight, but also your body fat %, and if you want body measurements.  I got a set of Salter body fat scales (about £15 I think)… and have been weighing myself once a week on a Wednesday morning to monitor my weight and body fat % (another good make is Tanita).

If you want to measure your body fat, I’d suggest getting a set of cheap body fat % scales and weigh yourself once a week at the same time (same conditions – ie no clothes on, before a shower etc).

Measuring changes in body fat percentage, rather than just measuring changes in weight, can be very motivational when you’re trying to lose weight – especially if you are exercising as part of your weight loss regime.

How can you easily work out your Ideal Weight?

I’ve created a Target Weight Calculator which will allow you to find out what your ideal body fat %, Ideal Weight, Training Weight and Racing Weight should be based on your age and sex.

Read on for more information on the calculations and body fat % target ranges:

What is your ideal weight and how can you work it out?

I worked out my ideal weight based on the BMI scale… if 18.5 is the lowest you should be, and 25 is the highest, then I aimed for the mid point: 21.75.  Don’t get me wrong, the BMI scale is an old scale, but for the general population it works.

You can work out your BMI by getting your height in metres squared, then divide your weight in kg.  I’m 1m 68,  and when my weight was 147lbs my BMI was as follows:

Weight in kgs: (147lbs / 2.2) = 66.8kg
Height in m squared: 1.68 x 1.68 = 2.8224
(to get height in metres from inches, multiply your height in inches by 2.54)
Weight in kgs / Height in m squared = 66.8 / 2.8224 = 23.7.

To get your ideal weight, take the mid point, and times it by your height in m squared, so for me:

21.75 x 2.8224 = 135lbs (9st 9lbs)

What is your ideal body fat %?

According to this source,  ideal body fat % ranges depend on your age and sex – see the table below:

People wanting to lose weight, should aim for the body fat ranges above. As a 30 year old woman, the range I should aim for is between 21-33%.  (It is important to note that these ranges are based on the average population, athletic people tend to have less body fat than in the ranges above. )

What about my ideal Racing Weight?

After lots of hard work, my weight is now 124 lbs (8st 12) and my body fat % is around 20-21%.

Although my weight and body fat are slightly lower than my ideal targets as stated above, I am training a lot and my weight is now more inline with the expected weights and % related with people who train, compete and exercise a lot. 🙂

Once you’ve reached your ideal weight through exercising, you may be interested in getting to your Ideal Training Weight and in the long term, your Ideal Racing Weight.

Being lighter makes it easier to run.. you are carrying less weight so you don’t have to work as hard.  But it’s a fine balance. You should have the strength in your body to enable you to keep going, and you want to be light to make it easier, but not too light or you might lose power/endurance.

What is your Ideal Racing Weight? 

Every endurance athlete has an ideal racing weight: a body-weight “sweet spot” that maximises performance. Individual racing weights are influenced by so many factors that it’s impossible to calculate or predict them with perfect accuracy. But it is possible to make an estimate that’s good enough to serve as a goal.

Ideal racing weight is determined primarily by body fat percentage. That’s because body fat is the primary source of excess body weight, and loss of excess body fat is the primary cause of the weight change that results from progressive training and improved diet. The following table presents ideal body fat ranges for endurance performance for men and women of different ages:

As you can see from above, my ideal ‘Racing Weight’ body fat % is between 7 – 18%.  Depending on the sport you compete in, your expected body fat % will vary, but the range above covers most sports.

I currently weigh 124lbs and my body fat % is 20.4%.
That means that 79.6% of my weight is lean body weight (bones etc).
79.6% of 124lbs = 99lbs. So my lean weight is 99lbs.
If I set myself a target of getting to 18% body fat, I would take 18% away from 1 = 82%.
Then divide my lean weight by that number = 99 / 0.82 = 120lbs.

So my ideal Racing weight is 120lbs, or 8 st 8.

Depending on where you are right now with your body fat % you might not want to aim directly for the body fat % detailed above.  The table below shows what you should aim for depending on your current body fat %:

What is your ideal training weight?

Your ideal training weight is up to 8% more than your ideal Racing Weight.

120lbs x 1.08 = 130lbs (9st 4). 🙂

Now, all that seems like a hell of a lot of calculations right?  Well, I’ve put it all into my easy to use Target Weight Calculator.

All you need to do is enter your sex, age and current weight and body fat %.  It will work out your Ideal Weight on the ‘Ideal Weight Calculator’ page.

And if you take a look at the ‘Racing Weight Body Fat %‘ table, generally we should aim in the long term to get to the 80th percentile, you can then set your body fat % goal on the ‘Training Weight Calculator’ page.  And it will workout your Racing Weight and your Target Weight.  😀

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7 Responses to Target Weight Calculator

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  5. Stacey Huebner says:

    I’d love to try this out but it seems the workbook pages are protected. Can they be unlocked?

  6. Pingback: My 3,000th post | Lorn Pearson Trains…

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