Sports Bra Size Calculator
Get a size recommendation, sister sizes, and the best support style for your workouts — with unit + region conversion built in.
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1 Underbust (snug)
Exhale normally, wrap tape under the breasts. Firm but not painful. Keep it level all around.
2 Overbust (fullest)
Measure around the fullest part. Tape should rest lightly—don’t compress the breast tissue.
3 Double-check
Take each measurement twice. If results differ, use the average.
4 Quick fit test
Jump test: band stays level, minimal bounce, no spillage. Adjust straps last.
Finding a sports bra that actually supports you during running, HIIT, CrossFit, or strength training shouldn’t feel impossible. Yet 7 out of 10 women still wear the wrong sports bra size, causing pain, bouncing, rubbing, shoulder strain, and early tissue stretching.
So we fixed it.
Welcome to the 2026 Sports Bra Size Calculator, built with real biomechanics, modern breast-shape science, and updated sizing logic for how breasts truly move during exercise. This guide is the most accurate, beginner-friendly, and science-backed sports bra fitting resource online.
This isn’t just another outdated “measure underbust + overbust” chart.
This tool understands real movement, real anatomy, and real workout demands.
Let’s get you a bounce-proof, pain-free, fully supported sports bra in under 60 seconds.
Why Most Women Wear the Wrong Sports Bra Size (2026 Data)
Decades of research from the University of Portsmouth, Wollongong, and Shock Absorber Labs prove one fact:
👉 Most women use their everyday bra size as their sports bra size — which is almost always incorrect.
Here’s what the wrong size causes:
| Issue (Wrong Size) | % of Women Affected | Long-Term Effect |
|---|---|---|
| Excessive breast bounce | 78% | Ligament stretching, sagging |
| Shoulder & neck pain | 62% | Postural imbalance, tension headaches |
| Chafing & skin irritation | 54% | Scarring, rashes, infections |
| Reduced workout performance | 41% | Lower intensity, low confidence |
| Band riding up | 37% | Zero support + discomfort |
The fix is simple:
✔ Measure correctly
✔ Use a modern sizing calculator
✔ Choose the right support level
How to Measure Yourself Correctly (2026 Expert Method)
You only need a soft measuring tape and 30 seconds.
The Sports Bra Size Calculator will do the math, but here’s how to measure like a pro:
1. Underbust Measurement (Band Size)
This is your most important measurement.
How to measure it:
- Place tape directly under your breasts
- Pull snug (not painfully tight)
- Keep it level around your torso
- Exhale normally
Pro tip:
A firm, accurate underbust measurement controls 70% of breast movement.
2. Overbust Measurement (Cup Volume)
This determines your cup size.
How to measure it:
- Measure around the fullest part of your chest
- Keep tape relaxed
- Stand upright, normal posture
- Wear a non-padded bra or go braless
3. Activity Level (Bounce Control Required)
Your support needs change with movement.
| Activity | Examples | Needed Support |
|---|---|---|
| Low | Yoga, Pilates, walking | Light compression |
| Medium | Strength training, cycling | Moderate support |
| High | Running, HIIT, cardio | Firm encapsulation / hybrid |
4. Breast Shape (Critical for Fit Accuracy)
Shape determines whether cups gape, press, or spill.
| Breast Shape | Visual Clue | Best Sports Bra | Problem if Ignored |
|---|---|---|---|
| Full on Top | Volume above nipple | Encapsulation, deep neckline | Spillage |
| Full on Bottom | Volume below nipple | Higher gore, molded cups | Gaping |
| Projected/Deep | Breasts extend forward | Deep cups, strong apex | Flattening |
| Shallow/Wide Root | Wide base, less projection | Wide wires, low apex | Cup wrinkling |
| East-West | Nipples point outward | Side-support panels | Side spillage |
The calculator uses this detail to fine-tune sizing for accuracy.
How the Sports Bra Size Calculator Predicts Your Fit
When you hit Calculate, you get three crucial results:
1. Traditional Bra Size (e.g., 34DD / 32F)
This helps when buying encapsulation sports bras with individual cups.
2. Sports Bra Compression Size (e.g., S, M+, L, XL)
Sports bras use compression sizing based on stretch and movement tolerance.
For example:
| Traditional Size | Compression Size | Best Use |
|---|---|---|
| 32A–34B | XS / S | Gym, yoga |
| 34C–36D | M | Running, HIIT |
| 34DD–36F | L | High-impact control |
| 38F+ | XL / XXL | Maximum support |
3. Support Level Recommendation
The tool matches your activity level + breast volume to:
- Light support
- Medium support
- High-impact support
- Maximum bounce control
2026 Sports Bra Size Conversion Table (Quick Reference)
| Underbust (in) | Overbust (in) | Traditional Size | Sports Bra Size | Support Recommendation |
|---|---|---|---|---|
| 27–28 | 32–33 | 32A | XS | Medium |
| 29–30 | 38–39 | 34DD | L | High Impact |
| 31–32 | 40–41 | 36E | XL | Maximum |
| 33–34 | 42–43 | 38F | XXL | Maximum + Wide Straps |
| 35–36 | 44–45 | 40G | 3X | Encapsulation Only |
(Your tool dynamically calculates exact values beyond the chart.)
3 Types of Sports Bras in 2026 (Which One You Actually Need)
1. Compression Sports Bras
Best for: A–C cups
Ideal for: Gym workouts, strength training
Support: ★★★☆☆
2. Encapsulation Sports Bras
Best for: D–J cups
Ideal for: Running, HIIT, jumping
Support: ★★★★★
3. Hybrid Sports Bras (Compression + Encapsulation)
Best for: All cup sizes
Ideal for: High-impact or mixed workouts
Support: ★★★★★
5 Red Flags Your Sports Bra Is Failing You
If ANY of these happen, re-measure immediately:
- Band crawls up your back
- Quad-boob or top spillage
- Side spill / underarm bulge
- Straps digging painfully
- You’re adjusting the bra every few minutes
- Your boobs move more than you do
A perfect fit eliminates all of these instantly.
Top 10 Sports Bra FAQs
1. How tight should a sports bra be?
Snug enough that the band stays level during jumping but comfortable enough to breathe deeply.
2. How do I know my sports bra size?
Measure your underbust + overbust and enter them in the Sports Bra Size Calculator for instant results.
3. Why do I need a different size for sports bras?
Sports bras control 3D movement (vertical, lateral, forward), while regular bras only provide lift.
4. What’s the best sports bra for running?
Encapsulation or hybrid bras with wide straps and strong bands — especially for DD+ sizes.
5. Can I wear the same bra for yoga and running?
No. Yoga needs comfort; running needs firm bounce control.
6. How often should I replace my sports bras?
Every 6–12 months or after 70+ washes.
7. Why do sports bras hurt my shoulders?
Straps are compensating for a loose band. You likely need a smaller band, bigger cup.
8. Do breast shapes affect sports bra sizing?
Yes. Shape determines cup capacity, strap placement, and support level.
9. Does cup size matter in sports bras?
Absolutely. Larger cups require deeper, more structured support.
10. What’s the fastest way to get an accurate sports bra size?
Use a two-measurement calculator (like ours), which adjusts for shape, movement, and compression.
Final Truth: Your Breasts Deserve Better
The right sports bra is not a luxury — it’s foundational workout gear.
One accurate measurement can fix:
✔ Pain
✔ Bounce
✔ Chafing
✔ Poor posture
✔ Low support
✔ Training discomfort
Your breasts work hard during workouts. Your bra should work harder.
Use the free Sports Bra Size Calculator now — it takes 45 seconds and gives you your exact 2026 size + support level.
Perfect fit → more confidence → better workouts.
Runner? HIIT? CrossFit?
You need maximum stability + zero bounce.
Let’s get your exact high-impact size.
🏃♀️ Calculate My High-Impact Fit →
