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Activity Level*

Optional fields – it’s ok to leave these blank, but you’ll get more interesting results if you fill them all in!

Intended Intake
Calories p/day

Finish Date

Goal Weight

Goal BMI

Frame Size READ THIS

How does the frame size adjustment work?

BMI is an imperfect tool for calculating whether your weight is healthy or not, because it doesn’t take into account the size and shape of your body – for example, a very petite, small boned person may have a BMI below the healthy range, despite being a healthy weight for her body type. Likewise, a very broad or muscular person may have a BMI in the overweight or even obese category, when really they’re not overweight at all, just larger-framed.

For this reason, the Ultimate Weightloss Calculator offers a frame size adjustment tool, to give you an alternate result if you feel the standard BMI formula doesn’t apply to you very well. If you choose “small frame size” or “large frame size”, the results are adjusted by 10%.

Because this adjusted formula is NOT medically approved. The adjusted results should DEFINITELY NOT be taken as medical advice.

What your BMR means

Your BMR (Basal Metabolic Rate) is the number of the calories you burn just to keep your body functioning, without taking your activity level into account. You would use this many calories even if you just lay in bed all day and didn’t move at all.

What your TDEE means

Your TDEE (Total Daily Energy Expenditure) is your BMR, plus a certain number of calories to take into account your activity level. It’s a rough guide to how many calories you need each day.

What your BMI means

BMI (Body Mass Index) is a measure used to quantify the mass of an individual, so they can be categorised according to their weight. It’s often used for health screening and provides a relatively objective measure of a person’s weight relative to their height. A high BMI generally indicates a high body fatness, but it is not diagnostic of this – for example, very tall people or athletes with considerable body mass often have misleadingly high BMI results.

Less than 15 = Very severely underweight

From 15.0 to 16.0 = Severely underweight

From 16.0 to 18.5 = Underweight

From 18.5 to 25 = Normal (healthy weight)

From 25 to 30 = Overweight

From 30 to 35 = Obese Class I (Moderately obese)

From 35 to 40 = Obese Class II (Severely obese)

Over 40 = Obese Class III (Very severely obese)

How fast should you lose weight?

It’s tempting to lose weight as fast as possible – but what’s the point, if you put it straight back on again? Losing weight gradually and healthily is the best way to ensure you maintain your goal weight when you reach it.

If you need to lose more than 20kg in total, 1kg per week is a realistic, healthy and maintainable weight loss rate to aim for.

If you need to lose between 10 and 20kg in total, 0.5kg per week is a realistic, healthy and maintainable weight loss rate to aim for.

If you need to lose less than 10kg, 0.25kg per week is a realistic, healthy and maintainable weight loss rate to aim for.


  1. nice pridiction. it works well

  2. Great! Thank you

  3. Sry, but I can’t click on submit ;(

  4. Hi!
    The M/F checkbox isn’t working anymore, it’s giving the F TDEE.
    Great job btw, I’ve been using it for a while!

  5. I have been using this website for about a year now since I started my weight loss plan. I must say the calculator is really great!
    I entered all the details and tried submitting but there is no result.


      Should be fixed now – please try again! If it still doesn’t work let me know in the comments and I’ll email you and we’ll figure out the problem 🙂

  6. Works perfect for me. Except that I have to eat less than I thought I needed to for my goals which is a bummer lol. It’s good to know though, now I have a greater chance of success. Thanks for this calculator. Happy New Year!

  7. Oh I just noticed a little mistake on the results page after clicking submit. At the top it says that I entered height 1.67cm,
    Obviously I am not less than 2cm tall, it means to say 1.67m or 167cm. All the calculations seem to have been done correctly regardless. I entered in cm, I entered 167cm.

  8. Thank you for such a great calculator – I love playing around with it!

    I do have a question, though: Are BMR and TDEE fixed in your calculations of when a goal weight will be reached? Or are they adjusted (lower weight -> lower BMR)?


      They’re not adjusted, I shall put it on my to do list! In the meantime I’d advise recalculating every time you lose 5kg or so – although the difference is likely to be small. Thanks for the comment, I’m glad you found the weight loss calculator useful 🙂

  9. Good tool thanks for building

  10. On my 17th birthday, I’m weighing 97kg. I’m determined to become a healthy weight by my 18th birthday. According to this calculator, I can consume approx 1700 a day to reach my goal, which is a lot more than I thought! I thought I’d have to go 1200 day by day. Thank you for making this calculator, it’s the most helpful one I’ve found. Wish me luck!

  11. Really great and helpful! Sadly it doesn’t work anymore when I click on submit:/

  12. I love this site.thank you so much,it has helped me and i still use it! 🙂

  13. I really love this site, but in the last few days i cant click on submit :c

  14. SUMBIT doesn’t work again!

  15. I used this weight loss calculator for the past three months and I found it very useful!
    Unluckily, I can’t click on “Submit” anymore.
    Is there something I’m doing wrong?
    Thank you in advance!

  16. The submit butto seems to have stopped working

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