Do Knix and The Period Company use the same absorbency labels?

No. Knix publishes 4 current tiers (15–99 mL across the range) and The Period Company publishes 3 (10–45 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 The Period Company sizes compare?

Knix tends to run small (many people size up); The Period Company 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.

Is Knix or The Period Company better?

Neither is better across the board - they differ on measurable things. Compare three numbers on this page: the millilitres at the tier you actually need (not the tier names), how each brand's sizing runs for your hip measurement, and current prices in the catalog. The right brand is the one whose numbers fit your flow and your body, and that answer differs by person.

Knix vs. The Period Company

How Knix and The Period Company 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 The Period Company (up to 45 mL) at its highest current tier. That does not make every Knix pair more absorbent than every The Period Company 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

The Period Company

See The Period Company

Tier	Capacity	Grade
Light (Thong)	10 mL	Data quality grade B, converted from tampon counts
Medium	20 mL	Data quality grade B, converted from tampon counts
Heavy	45 mL	Data quality grade B, converted from tampon counts

Verified against The Period Company'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 under 3 mL each, 2 mL on average, 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); The Period Company 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

The Period Company: Runs true to size. Product pages state verbatim: "This style runs true to size. Order your most standard size."

Quick answers

Is Knix or The Period Company more absorbent?: By their own published claims, Knix reaches a higher maximum capacity (up to 99 mL) than The Period Company (up to 45 mL) at its highest current tier. That does not make every Knix pair more absorbent than every The Period Company 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 The Period Company use the same absorbency labels?: No. Knix publishes 4 current tiers (15–99 mL across the range) and The Period Company publishes 3 (10–45 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 The Period Company sizes compare?: Knix tends to run small (many people size up); The Period Company 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.
Is Knix or The Period Company better?: Neither is better across the board - they differ on measurable things. Compare three numbers on this page: the millilitres at the tier you actually need (not the tier names), how each brand's sizing runs for your hip measurement, and current prices in the catalog. The right brand is the one whose numbers fit your flow and your body, and that answer differs by person.

Skip the comparison - get your answer

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

What absorbency do I need?Find my size