Advanced Calculator
Enter three underbust and three bust measurements. The tool estimates band tension, cup depth, sister sizes, and common regional conversions.
Example Data Table
| Tight Underbust | Snug Underbust | Loose Underbust | Standing Bust | Leaning Bust | Lying Bust | Estimated UK Size |
|---|---|---|---|---|---|---|
| 29 in | 30 in | 31 in | 37 in | 38 in | 36.5 in | 30FF |
| 31 in | 32 in | 33 in | 38 in | 39 in | 37.5 in | 32F |
| 33 in | 34 in | 35 in | 41 in | 42 in | 40 in | 34FF |
Formula Used
The calculator first converts all measurements to inches. The weighted underbust is calculated as:
(tight × 0.25) + (snug × 0.60) + (loose × 0.15).
The band is rounded to the nearest even number. The relaxed option adds one band step. The firm option may reduce one band step when the underbust range is large.
The effective bust uses a weighted or simple average. Cup difference is:
effective bust - band size. Each inch of difference moves about one cup step.
UK cup progression is used for the main Freya-style result.
How to Use This Calculator
Use a soft tape. Measure under the bust while breathing normally. Take tight, snug, and loose readings. Then measure the bust while standing, leaning, and lying. Enter all values in one unit. Pick your band preference. Press the calculate button. Review the UK result first. Then compare sister sizes.
Understanding Freya Bra Size Estimates
Why Measurements Matter
A bra size is not only a clothing label. It is a balance of band tension, cup volume, wire width, and fabric stretch. The band carries most support. The cups hold and shape the breast tissue. A small change in either area can change comfort.
Band Physics and Support
The band works like a circular support system. It wraps around the rib cage. When it is firm, it resists downward force. When it is too loose, the straps work harder. This can cause slipping, digging, or a lifted back band. The calculator uses tight, snug, and loose readings to estimate a practical band size.
Cup Volume and Shape
Cup size depends on the difference between bust depth and band size. It is not fixed across bands. A 30FF and a 32F can hold similar volume. These are called sister sizes. Shape also matters. A shallow shape may need less cup depth. A fuller shape may need more cup depth. That is why the calculator includes a fullness option.
Using the Result Wisely
Treat the result as a strong starting point. Freya styles can vary by fabric, cup cut, and wire shape. Try the suggested size first. Then test the sister sizes. The center gore should sit close. The band should stay level. Cup edges should not cut in or gape. Good fit should feel secure, stable, and wearable for daily movement.
FAQs
1. Is this an official Freya calculator?
No. It is an independent fitting estimate. It uses common UK bra sizing logic and measurement-based calculations.
2. Which result should I trust first?
Use the UK size first because Freya commonly labels bras with UK sizing. Then review the conversions as approximate guides.
3. Why does the calculator use three bust measurements?
Different positions reveal different breast volume. Standing, leaning, and lying measurements help estimate cup depth more realistically.
4. What is a sister size?
A sister size has similar cup volume with a different band. Going up a band usually means going down one cup step.
5. Should I use inches or centimeters?
You can use either. Select the unit before calculating. The script converts centimeter inputs to inches internally.
6. Why is the plus-four method included?
Some users prefer older fitting logic. Modern fitting often uses a snug underbust method, but both options are available.
7. What if my result feels too tight?
Try the relaxed band option or test the sister size with a larger band and smaller cup.
8. Can this calculator replace a fitting session?
No. It gives an estimate. Real fit also depends on body shape, style, wire width, and fabric stretch.