Breast Weight Calculator
How much do breasts weigh? For most bra sizes, between about 0.25 and 1.5 kilograms per breast, and the estimate follows from cup volume: pick your size below and the calculator converts its volume to weight at typical breast tissue density (roughly 0.9 grams per cc).
The number is worth knowing for one practical reason: it is the load your bra band carries all day, and it explains physically why band fit dominates comfort at fuller sizes.
An estimate from geometry, not a scale reading: tissue composition varies. Runs in your browser; nothing stored.
| Size (US) | Per breast | Pair |
|---|---|---|
| 32B | 0.16 kg | 0.31 kg (0.7 lb) |
| 32D | 0.63 kg | 1.25 kg (2.8 lb) |
| 32DDD | 1.41 kg | 2.82 kg (6.2 lb) |
| 34B | 0.17 kg | 0.33 kg (0.7 lb) |
| 34D | 0.66 kg | 1.33 kg (2.9 lb) |
| 34DD | 1.04 kg | 2.08 kg (4.6 lb) |
| 34DDD | 1.50 kg | 2.99 kg (6.6 lb) |
| 36C | 0.40 kg | 0.79 kg (1.7 lb) |
| 36DD | 1.10 kg | 2.20 kg (4.8 lb) |
| 36G | 2.15 kg | 4.31 kg (9.5 lb) |
| 38D | 0.74 kg | 1.49 kg (3.3 lb) |
| 38DDD | 1.67 kg | 3.34 kg (7.4 lb) |
The method, stated honestly
We approximate each cup as a half-ellipsoid whose depth comes from the cup letter's inch difference and whose base scales with the band, calibrated against published volumetric fitting data, then multiply by tissue density around 0.9 g/cc (breast tissue is a fat and gland mix slightly lighter than water). The result is a genuine estimate with real variance: dense glandular tissue weighs more per cc than softer fatty tissue at identical volume.
Published surgical literature, where breast weight is actually measured, broadly supports these ranges: reduction specimens for DD-and-up patients commonly run 400 to 1,200 grams per side. Treat the calculator as scale-of-magnitude truth, not gram precision.
What the weight means for support
A 34DD pair at roughly 1.5 to 2 kilograms is the weight of a laptop, suspended from your torso through fabric. Distributed across a firm, level band, that load disappears into the ribcage; transferred to two shoulder straps by a loose band, it becomes grooves and neck strain by afternoon. This is the physics behind our repeated advice that the band carries 80 percent of support, and why sports bras exist: running multiplies effective load several times over per stride.
Frequently asked questions
Last updated August 2026.