↔ Complete Comparison Directory · 2026 Edition

Breast Size Comparisons:
Every Size, Explained Simply

Band differences, cup volume, sister sizing, and which size actually fits better — all in one place. No guesswork. No jargon. Just clear answers.

80+ size comparisons A–Z full directory 28–42 band covered A–H cup included Sister sizing explained
🎯 Find My Exact Size First Browse All Comparisons ↓
⚡ Interactive Tool

Compare Any Two Bra Sizes Instantly

Pick Size A and Size B — get band difference, cup volume, sister sizing, and a side-by-side silhouette in seconds.

📏 Band difference (in + cm) ⚖️ Volume difference (cc) 🔄 Sister size match 👙 Visual silhouette 📈 % volume difference

Extended Bands 28–60 • Cups AA–P • 7 Systems

Visual Bra Size Comparison

See the real difference between any two sizes — volume, band, cup steps, sister sizes, and international equivalents.

SVG visual comparison True volume math Sister size chain US • UK • EU • FR • AU • JP
Size A — first size
34B
vs
Size B — compare to
36C
Input system:
Quick comparisons
34B
vs
36C
Sister size chain for Size A
International equivalents US • UK • EU • FR • AU • JP
SystemSize ASize B
Volume estimates are proportional approximations for comparison only — actual breast volume varies by shape, tissue density, and projection. Sister sizes share equivalent cup volume in theory; real fit depends on shape and brand. Always try multiple sizes.

🌍 International users: Tool uses US sizing. Use the Global Size Converter for UK · EU · AU · JP standards.

Popular tries: 34B vs 36C 32D vs 34C 36D vs 38C 34DD vs 36D D cup vs DD cup

Here’s what the bra industry never explains clearly: the same cup letter doesn’t mean the same size. A 34B and a 36B look identical on the label but hold different amounts of volume. A 32D and a 34C look totally different on paper — yet they’re actually the same size underneath.

This directory is built to fix that confusion. Every comparison page covers the measurements, the math, the fit signs, and the exact situations where one size works better than the other. Click any comparison below to get the full breakdown.

⚡ Quick start

How to Use This Directory

Don’t know your size?

Start with the Bra Size Calculator. Get your band and cup in 2 minutes. Then come back to compare.

Band feels wrong?

Use sister size logic: go up/down one band and flip the cup. Same volume, different comfort. Find it in the comparisons.

Open a comparison

Read the quick answer first (10 seconds). Then scan the fit signs to confirm which size works on your body.

Shopping across brands?

Sizes shift by brand. After comparing, use the Brand Size Decoder to decode VS, Aerie, ThirdLove & more.

🔥 Most searched

Most Popular Comparisons

The comparisons women search most — answered with volume data, fit signs, and sister size alternatives.

🔥 Trending

34D vs 36C — Which Fits Better?

Band tightness vs cup volume trade-off. 34D gives more support; 36C trades tightness for volume. Full fit signs included.

Read comparison →
🔄 Sister Sizes

32D vs 34C — Same Volume, Different Feel

Classic sister sizes. Identical cup volume — but 32D grips tighter. Switch if your band digs in without fixing the cups.

Read comparison →
📊 Volume Jump

34C vs 34D — One Cup Up, What Changes?

Same band, one cup difference. About 150–250cc more per breast. Covers how projection, spillage risk, and straps are affected.

Read comparison →
🔄 Sister Sizes

32DD vs 34D — Same Cup Volume?

Yes — these are sister sizes. Same breast volume, different band tension. Ideal comparison for women between band fits.

Read comparison →
💬 Common Question

D Cup vs DD Cup — What’s the Real Difference?

One full cup step. Roughly 150–250cc more volume. “DD” sounds bigger than it looks on many frames — context matters here.

Read comparison →
📊 Volume Jump

36C vs 36D — Containment vs Comfort

Same band, bigger cup. When to size up from C to D on a 36 band — using overflow, gaping, and underwire placement as signals.

Read comparison →
⚖️ Reference

Breast Volume by Cup Size (34 Band)

Approximate averages. Volume increases with band size too — a 36C holds more than a 34C.

34A
200–250 cc
~0.4–0.5 lb each
34B
350–400 cc
~0.7–0.9 lb each
34C
500–600 cc
~1.1–1.3 lb each
34D
650–800 cc
~1.4–1.8 lb each
34DD
800–1,000 cc
~1.8–2.2 lb each
34DDD
1,000–1,200 cc
~2.2–2.6 lb each

👉 Want exact numbers? Use the Breast Volume Calculator

🔄 Sister sizing explained

Sister Size Chart

Each row shares the same cup volume. Move left for a tighter band, right for a looser one.

← Tighter Band Center Size Looser Band → Relationship
32A 34AA 36AAA Sister
32B 34A 36AA Sister
32C 34B 36A Sister
32D 34C 36B Sister
32DD 34D 36C Sister
32DDD34DD 36D Sister
34DDD36DD 38D Sister
36DDD38DD 40D Sister
38DDD40DD 42D Sister

Rule: go up one band + down one cup = same volume. Down one band + up one cup = same volume. Use the Sister Size Calculator for any size instantly.

📚 Full directory

All Bra Size Comparisons A–Z

Organized by band size. Every page covers volume difference, sister sizing, and exact fit advice.

28
28 Band Comparisons
8 comparisons
28A vs 28B 28B vs 28C 28B vs 30A Sister 28C vs 30B Sister 28D vs 30C Sister 28D vs 28DD 28DD vs 30D Sister 28C vs 28D
30
30 Band Comparisons
10 comparisons
30A vs 30B 30B vs 30C 30C vs 30D 30D vs 30DD 30B vs 32A Sister 30C vs 32B Sister 30D vs 32C Sister 30DD vs 32D Sister 30DDD vs 32DD Sister 30DD vs 30DDD
32
32 Band Comparisons
17 comparisons
32A vs 32B 32B vs 32C 32C vs 32D 32C vs 36C 32D vs 32DD 32DD vs 32DDD 32B vs 34A Sister 32C vs 34B Sister 32D vs 34C Sister 32DD vs 34D Sister 32DDD vs 34DD Sister 32B vs 32D 32C vs 34C 32C vs 34D 32C vs 36B 32D vs 32DDD 32DD vs 34C
34
34 Band Comparisons — Most searched band size
26 comparisons
34A vs 34B 34B vs 34C 34B vs 38B 34B vs 32D 34C vs 32DD 34C vs 38C 34C vs 34D 34D vs 34DD 34DD vs 34DDD 34B vs 36A Sister 34C vs 36B Sister 34D vs 36C Sister 34DD vs 36D Sister 34DDD vs 36DD Sister 34B vs 36B 34B vs 36C 34C vs 36C 34D vs 36D 34DD vs 36C 34A vs 36A 34B vs 34D 34C vs 34DD 34D vs 34DDD 34DD vs 36DD 34G vs 36F Sister 34H vs 36G Sister
36
36 Band Comparisons
20 comparisons
36A vs 36B 36B vs 36C 36B vs 34D 36C vs 34DD 36C vs 36D 36D vs 36DD 36DD vs 36DDD 36B vs 38A Sister 36C vs 38B Sister 36D vs 38C Sister 36DD vs 38D Sister 36DDD vs 38DD Sister 36B vs 36D 36C vs 38C 36D vs 38D 36DD vs 38C 36C vs 36DD 36D vs 36DDD 36F vs 38E Sister 36G vs 38F Sister
38
38 Band Comparisons
14 comparisons
38A vs 38B 38B vs 38C 38C vs 38D 38D vs 38DD 38DD vs 38DDD 38B vs 40A Sister 38C vs 40B Sister 38D vs 40C Sister 38DD vs 40D Sister 38DDD vs 40DD Sister 38C vs 40C 38D vs 38DDD 38F vs 40E Sister 38G vs 40F Sister
40
40 Band Comparisons
10 comparisons
40A vs 40B 40B vs 40C 40C vs 40D 40D vs 40DD 40DD vs 40DDD 40B vs 42A Sister 40C vs 42B Sister 40D vs 42C Sister 40DD vs 42D Sister 40DDD vs 42DD Sister
42
42 Band Comparisons
10 comparisons
42A vs 42B 42B vs 42C 42C vs 42D 42D vs 42DD 42DD vs 42DDD 42B vs 44A Sister 42C vs 44B Sister 42D vs 44C Sister 42DD vs 44D Sister 42DDD vs 44DD Sister
Cup
Cup Letter Comparisons (Band-Independent)
10 comparisons
A Cup vs B Cup B Cup vs C Cup C Cup vs D Cup D Cup vs DD Cup DD Cup vs DDD Cup DDD Cup vs G Cup E Cup vs F Cup F Cup vs G Cup G Cup vs H Cup B Cup vs D Cup
🔍

No comparisons found

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🛠 Related tools

Complete Fit Toolkit

These tools work together. Start with the calculator, then use comparisons to dial in your exact fit.

⭐ Start Here

Free Bra Size Calculator

Don’t know your size? Enter your underbust and overbust in 60 seconds. Get your band, cup, sister sizes, and fit tips.

Calculate my size →
📊 Visual Tool

Visual Comparison Tool

Choose any two sizes and see side-by-side silhouettes, volume difference in cc, band difference in inches, and sister-size relationship.

Compare visually →
🔄 Sister Sizes

Sister Size Calculator

Enter your size and instantly find every sister size — both tighter and looser bands — with volume confirmation for each.

Find sister sizes →
🌍 International

Global Bra Size Converter

Convert US ↔ UK ↔ EU ↔ JP ↔ AU instantly. Essential for shopping Freya, Wacoal, Chantelle, or any international brand.

Convert sizes →
🏷 Brand Fit

Brand Size Decoder

Victoria’s Secret, Aerie, ThirdLove, and Savage X Fenty all fit differently. Find your actual size for each brand before buying.

Decode my brand →
🤖 AI-Powered

AI Smart Fit Calculator

Beyond measurements — analyzes your breast shape, projection, and fullness to recommend the right style for your body.

Get AI recommendations →
❓ Quick answers

Bra Size Comparison FAQ

The most searched questions — answered clearly, without the jargon.

It means comparing two bra sizes based on band measurement, cup volume, and the mathematical difference between them. Because a cup letter means different things on different band sizes, “comparison” clarifies whether two sizes are similar, identical (sister sizes), or genuinely different in volume.
No. Even though they share the same cup letter, 36B holds more volume than 34B. A 34B has a 34″ band and 36″ bust. A 36B has a 36″ band and 38″ bust. Both are a 2-inch difference, but the 36B is built on a larger frame — so total cup volume is greater. 36B actually equals 34C in volume (they’re sister sizes).
Sister sizes share the same cup volume but have different band sizes. The rule: go up one band and down one cup (same volume, looser band) or down one band and up one cup (same volume, tighter band). Example: 34C sister sizes are 32D (tighter) and 36B (looser). Use sister sizes when your cups fit but your band doesn’t.
Yes — in terms of cup volume, they’re sister sizes. The breast tissue capacity is essentially the same. The key difference is band tension: 32D grips tighter, 34C feels looser. If your 32D cups fit but the band digs in uncomfortably, 34C is the natural switch. The cups will look and feel the same; only the band pressure changes.
DD is one cup step larger than D. In measurement terms, D = 4-inch bust-to-underbust difference, DD = 5 inches. That translates to roughly 150–250 cc more volume per breast — similar to the jump from C to D. DD also tends to require wider straps and stronger band construction to distribute the added weight properly.
Because bra size is a ratio, not a visual. A 34C on a petite narrow ribcage looks much more prominent than the same 34C on a broader athletic build — even though the measurement is identical. Breast shape (projected vs shallow, full-on-top vs bottom), root width, and body proportions all change how a size appears. This is why visual comparisons on different bodies are more useful than labels alone.
In the US, 34DD (or 34DDD) is currently reported as the most common average size — a significant shift from the 34B average cited decades ago. This reflects both body changes and improved fitting awareness: more women are now getting professionally measured and finding their real size instead of defaulting to an estimated small.
Signs you need a size change: band rides up your back (too loose — go down a band, up a cup), cups overflow at the top or sides (too small), cups gap or pucker (too big), underwire pokes into breast tissue (wrong cup shape or too small), or straps dig despite being loosened (band not doing its job). If any of these sound familiar, use the comparisons here to find your adjustment.

Not Sure Which Size to Compare?

Start with the Bra Size Calculator to find your true size in under 2 minutes — then use this directory to understand every adjustment from there.

🎯 Find My True Size First Visual Comparison Tool Sister Size Calculator

📏 All volume estimates based on US bra sizing standards (1 inch per cup step). Actual fit varies by brand, construction, and body shape.

🔒 No personal data collected or stored. Re-measure every 6–12 months — your size changes more than you think.

Bra Size Calculator Comparison Tool Size Converter Cup Size Photos Volume Calculator