Do Knix and Saalt use the same absorbency labels?

No. Knix publishes 4 current tiers (15–99 mL across the range) and Saalt publishes 4 (10–50 mL). Even where the words overlap, the millilitres differ, which is exactly why this page compares them in millilitres with a data-quality grade on every number.

How do Knix and Saalt sizes compare?

Knix tends to run small (many people size up); Saalt runs true to size. Both size from your hip measurement, so the size finder gives your size in each brand directly rather than guessing from the other brand's number.

Knix vs. Saalt

How Knix and Saalt period underwear compare on the only thing that travels across brands - capacity in millilitres - plus how each one's sizing runs. No brand's thumb on the scale.

Updated 2026-06-12 · Every capacity is the brand's own claim, graded and dated

By their own published claims, Knix reaches a higher maximum capacity (up to 99 mL) than Saalt (up to 50 mL) at its highest current tier. That does not make every Knix pair more absorbent than every Saalt pair - it means the top of Knix's range is higher. Compare tier by tier in millilitres, not by the label words.

Absorbency tiers, side by side

Knix

See Knix

Tier	Capacity	Grade
Light	5–15 mL	Data quality grade B, converted from tampon counts
Moderate	18–36 mL	Data quality grade C, conflicting / unconfirmed claim
Heavy	36–63 mL	Data quality grade C, conflicting / unconfirmed claim
Ultra	63–99 mL	Data quality grade C, conflicting / unconfirmed claim

Verified against Knix's own pages 2026-06-11

Saalt

See Saalt

Tier	Capacity	Grade
Light	10 mL	Data quality grade B, converted from tampon counts
Regular	15 mL	Data quality grade B, converted from tampon counts
Heavy	20 mL	Data quality grade B, converted from tampon counts
Super	40–50 mL	Data quality grade B, converted from tampon counts

Verified against Saalt's own pages 2026-06-11

Claims, not lab measurements

Every capacity above is the brand's own maximum claim, typically from a saline saturation test. The only published study with real blood components (BMJ Sexual & Reproductive Health, 2023) measured period underwear holding about 1 to 3 mL before leaking - far below these maximums. Use the numbers to compare the two brands like for like, not as a leak-free guarantee.

Sizing

Knix tends to run small (many people size up); Saalt runs true to size. Both brands size from your hip measurement, so rather than converting one brand's size into the other's, the size finder gives you your size in each directly.

Knix: Brand labels core styles "True to Size" on product pages (e.g. Essential High Rise). However, customer reviews consistently report the leakproof styles run small / recommend sizing

Saalt: No explicit runs-small/large statement on the main Saalt Wear size chart page; waist is "measured at your belly button" and hips "measured around the widest part of your hips." Bra

Quick answers

Is Knix or Saalt more absorbent?: By their own published claims, Knix reaches a higher maximum capacity (up to 99 mL) than Saalt (up to 50 mL) at its highest current tier. That does not make every Knix pair more absorbent than every Saalt pair - it means the top of Knix's range is higher. Compare tier by tier in millilitres, not by the label words. And remember these are saline-lab maximums, not leak-free guarantees - the only blood-component study measured far lower real capacity.
Do Knix and Saalt use the same absorbency labels?: No. Knix publishes 4 current tiers (15–99 mL across the range) and Saalt publishes 4 (10–50 mL). Even where the words overlap, the millilitres differ, which is exactly why this page compares them in millilitres with a data-quality grade on every number.
How do Knix and Saalt sizes compare?: Knix tends to run small (many people size up); Saalt runs true to size. Both size from your hip measurement, so the size finder gives your size in each brand directly rather than guessing from the other brand's number.

Skip the comparison - get your answer

Tell the translator your flow and it gives the covering tier at both Knix and Saalt. Tell the size finder your hip and it gives your size in each.

What absorbency do I need?Find my size