Understanding 40F Bra Size
A 40F bra size is considered a medium band size with an extra large cup size. This size is perfect for people with an average frame and extra large breast volume. Let's explore what makes this size unique and how to find the perfect fit.
Is 40F considered big or small?
Fast facts about 40F
- Snug 40 band with a 7-inch cup jump.
- Standing bust around 46.5–47.5 in keeps the cup filled.
- Share cup volume with 38G, 42E for band tweaks.
- Always scoop-and-swoop and check the gore for a flat anchor.
How 40F is measured
Band fit
Aim for a snug 38.5–39.5 in underbust so the 40 band stays level without digging.
Cup depth
Standing bust in the 46.5–47.5 in range keeps roughly a 7-inch cup difference.
Support focus
Choose firm wings, fully adjustable straps, and swap sister sizes if the band shifts during wear.
40F bust size in inches
| Measurement | Typical inches | How to capture it |
|---|---|---|
| Snug band (ribcage) | 38.5–39.5 in | Measure firmly under the bust on an exhale, then round to the band label. |
| Standing bust | 46.5–47.5 in | Keep the tape level across the fullest point while standing tall. |
| Band-to-bust difference | ≈7 in | Subtract your snug band from the standing bust to confirm cup depth. |
| Approx. cup depth | 8.5–9.5 in | Measure from the underwire root to the apex on a well-fitting bra. |
40F bust size in centimeters
| Measurement | Typical cm | How to capture it |
|---|---|---|
| Snug band (ribcage) | 97.8–100.3 cm | Measure firmly beneath the bust, then map it to EU/FR/JP band labels. |
| Standing bust | 118.1–120.7 cm | Keep the tape level across the fullest point without compressing tissue. |
| Band-to-bust difference | ≈17.8 cm | Use the difference to double-check your metric cup depth. |
| Approx. cup depth | 21.6–24.1 cm | Trace from underbust to apex on a supportive bra to check projection. |
- Falls inside the 32-36 band range most people wear, giving a familiar fit baseline.
- Extends beyond the sizing most stores stock, so it often looks full even on wider bands.
- Monitor posture and band tension—small shifts change how the size looks.
- Try sister sizes 38G, 42E to fine-tune band tension.
Quick reference for 40F
- 40F ≈ band 40 label with a 7-inch cup step.
- Projected bust lands around 46.5–47.5 in.
- Use the calculator to convert this size across US/UK/EU/JP systems.
Ranges are approximations—double-check your own measurements for precision.
40F across popular sizing systems
Match US 40F to the most searched regional labels without leaving this guide.
Currently showing the United States (US) label — copy 40F to match tags instantly.
United States (US)
40F
United Kingdom (UK)
40E
Europe (EU)
90G
France (FR)
105G
Japan (JP)
95G
Australia (AU)
18F
Quick converter
Switch systems and copy the exact label for checkout forms or bra tags.
Need step-by-step help? Jump into the dedicated guides below for measurement nuances and shopping tips.
Perfect For
- Average frames
- Medium ribcages
- Extra large breast volume
- Advanced support needs
Recommended Styles
T-Shirt Bras
Perfect for everyday wear under fitted clothing
- Seamless
- Molded cups
- Comfortable
Balconette Bras
Great for creating a natural lift and shape
- Wide-set straps
- Lower cut cups
- Enhancing
Plunge Bras
Ideal for low-cut tops and dresses
- Deep V-neck
- Minimal coverage
- Versatile
How 40F tends to look
40F pairs a 40-band with a 7-inch cup jump, so the silhouette changes with your frame and bra style.
- Keep 38G, 42E in mind—they share cup volume while tweaking the band.
- Shape, strap placement, and fabric choice all influence whether the size looks subtle or bold.
40F compared with nearby sizes
Quick reference when you’re deciding whether to change the band, the cup, or both.
- 40E is one cup shallower—switch when 40F wrinkles along the neckline.
- 40G adds depth while keeping the band snug if you spill out of 40F.
- 38G / 42E keep the same cup volume but tweak band tightness for comfort.
Sister size playbook
- Try 38G when you need tighter or looser band support.
- Try 42E when you need tighter or looser band support.
Fit checks before you buy
When trying on 40F bras, look for these key fit indicators:
- The band should fit snugly around your ribcage
- Cups should fully contain your breasts without spillage
- Straps should stay in place without digging in
- The center gore should lie flat against your chest
- Keep the band parallel to the floor on the middle hook.
- Scoop and swoop tissue into the cups before checking the gore.
- Adjust straps for lift, then reassess comfort after an hour of wear.
Remember that fit can vary between brands and styles. Always try on bras before purchasing to ensure the perfect fit.
Common 40F questions
What size is 40F in other systems?
40F converts to 40E in UK sizes, 90G in EU, 105G in FR, 95G in JP, and 18F in AU.
What does 40F mean?
40F pairs a 40 band with a cup that is roughly 7 inches deeper than the band measurement.
Which sister sizes match 40F?
40F shares cup volume with 38G, 42E. Use them to tighten or relax the band.
How can I confirm this is my best fit?
Measure snug and standing bust, check for smooth cup edges, and ensure the band stays level after a few minutes of wear.
Check 40F with our tools
Measure with the calculator, compare sister sizes, and review the perception guide for styling tips.