How to Size Vintage Bras vs. Modern-Day Bras: A Guide to Measuring

Finding the perfect bra fit can be tricky, especially when dealing with the differences between vintage and modern sizing. This guide explains the key differences and provides step-by-step instructions on where and how to take your measurements for each style.

Understanding Vintage vs. Modern Bra Sizing

Vintage Bra Sizing

Measurement System: Historically, vintage bras often used a different band and cup size calculation than today.

Band Size: In many cases, vintage band sizes were calculated by taking your underbust measurement and adding 4 or 5 inches, especially before the 1980s.

Cup Size: Cup letters were typically determined by the bust-over-band difference, but the increments and labeling could vary substantially.

Modern Bra Sizing

Measurement System: Today’s bras generally use a more direct approach, relying less on “+4 inches” rules and focusing on actual body measurements.

Band Size: Usually matches your underbust measurement in inches (rounded to the nearest even number).

Cup Size: Calculated by the difference in inches between the fullest part of your bust and your band size; every inch typically equals one cup size (A, B, C, etc.).

Where to Take Your Measurements

Proper sizing for both vintage and modern bras starts with two key measurements:

1. Band Size (Underbust Measurement)

How: Using a soft tape measure, wrap it snugly around your ribcage, directly under your bust.

Tip: Ensure the tape is level and parallel to the floor for accuracy.

2. Bust Size (Overbust/Fullest Part)

How: Measure around the fullest part of your bust, keeping the tape straight but not tight.

Step-by-Step: Calculating Your Size

Vintage Bra Sizing

Step	What to Do
Measure underbust	Wrap tape under the bust, note the measurement
Add inches	Add 4 if even, 5 if odd (the “+4 inches” method)
Measure bust	Measure the fullest part of the bust
Find cup size	Subtract band from bust; use old charts to find letter

Example:

Underbust = 30″, add 4 → Band size = 34″

Bust = 36″; 36 - 34 = 2″ difference → likely a B cup in vintage sizing

Modern Bra Sizing

Step	What to Do
Measure underbust	Tape under bust; round to nearest even inch
Band size	Use this number directly as band size
Measure bust	Measure bust at fullest part
Find cup size	Bust minus band = cup size (1″ = A, 2″ = B, etc.)

Example:

Underbust = 32″ → Band size = 32

Bust = 36″; 36 - 32 = 4″ difference → D cup

Quick Comparison Table: Vintage vs. Modern Sizing

	Vintage Bras	Modern Bras
Band calculation	Underbust + 4 (or 5) inches	Actual underbust (rounded)
Cup calculation	Bust - band via old chart	Bust - band (1" per cup)
Fit expectation	Snug in the rib, less stretch	Snug but more flexible

 

Tips for Shopping or Sewing Vintage

Always check the original size chart for the era or brand.

When shopping for vintage, know your “vintage size,” which may be several numbers higher than your modern one.

Consider trying the item on if possible, as stretch and fabric composition can vary widely.

When sewing vintage patterns, use your direct body measurements but adjust based on historical sizing methods.

Vintage bra shopping brings a unique blend of style and nostalgia, but knowing your correct size is key for comfort and fit. Measure carefully, understand the sizing system in play, and you’ll enjoy the best of both worlds.