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Instant Calculation
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Recommends a breast pump flange (breast shield) size from a nipple diameter measurement, using standard manufacturer sizing guidance: the flange tunnel should be roughly 3-4 mm larger than nipple diameter, to allow room for the nipple to move without excess areola being pulled in. This is a product-fit reference tool, not a medical tool — actual comfort during pumping is the best guide, and a lactation consultant can help with fit issues.
How it works
Measure your nipple diameter (not including areola) in millimeters and enter it. The tool adds the standard 3-4 mm allowance and suggests the closest common commercial flange size.
- Enter nipple diameter (mm).
- Click Calculate to see your results.
Examples
Nipple diameter 17 mm
Recommended range: 20-21 mm; closest common size: 21 mm.
Who should use it
- Choosing a starting flange size for a new breast pump.
- Troubleshooting pumping discomfort alongside a lactation consultant.
Industry applications
- Breast pump retailers and fitting guides
- Lactation consultant practice
Advantages
- Quick starting point based on standard sizing guidance.
- Suggests the closest common commercial size available.
Limitations
- Manufacturers vary slightly in their exact sizing conventions.
- Comfort during actual use is still the deciding factor.
Common mistakes to avoid
- Measuring nipple diameter including the areola, which inflates the measurement.
- Assuming flange size never needs to change — sizing can change over the breastfeeding/pumping journey.
Best practices
- Re-measure periodically, especially in the early weeks, as swelling and pumping adjust nipple size.
Tips
- If between two sizes, many users find comfort improves by trying the larger size first.