Concentration Ranges vs Exact Percentages on an SDS

You open a supplier's safety data sheet looking for a clean number to plug into your filing, and instead of "3 percent" you get "1 to 5 percent." It's mildly infuriating when you're trying to be precise, and there's a real reason it happens, along with a real way to work around it.

Why suppliers give ranges instead of exact numbers

Section 3 of an SDS lists the composition of the material, and suppliers deliberately publish ranges rather than exact percentages for a couple of reasons. First, formulations get minor batch-to-batch tweaks for manufacturing reasons that don't meaningfully change performance, and a range covers that natural variation without requiring a new SDS every time. Second, and more commonly, ranges protect proprietary formulation details. If a supplier tells every customer the exact percentage of a key functional ingredient in their blend, that's effectively handing over the recipe. A range gives you enough information to assess hazard and regulatory status without disclosing the precise formula.

Both reasons are legitimate. Neither one helps you when you need a specific percentage for a Cosmetic Notification Form.

What to do with a range

You have a few real options, roughly in order of how reliable they are:

1. Ask the supplier directly for the exact percentage under a confidentiality agreement. Many suppliers will provide the specific number, or at least a tighter range, if you ask and sign an NDA, especially if you're a repeat customer. This is the cleanest path if it's available to you.
2. Use the midpoint of the range as a working estimate, and say so. If the SDS says 1 to 5 percent, using 3 percent as your filing value is a reasonable, defensible default when the supplier won't share more, as long as you keep a note of your methodology in case a regulator ever asks how you arrived at that number.
3. Use the top of the range if you need a conservative, worst-case estimate. For allergen threshold calculations in particular, where you're checking whether a component crosses a disclosure trigger, using the top end of the range is the safer assumption. If even the worst case falls comfortably under a threshold, you can be confident the actual value does too.
4. Never quietly use the bottom of the range to dodge a threshold. If you pick the low end specifically because it lets you avoid disclosing an allergen or avoid tripping a restriction, and the true value turns out to be higher, that's a real compliance risk sitting under an assumption you chose for convenience rather than accuracy.

Carrying the range through a blend calculation

This gets more complicated with supplier blends, which is most of what small makers actually buy. If your fragrance blend's SDS lists a component at "1 to 5 percent" of the blend, and you use the blend at 2 percent of your finished formula, your finished-product concentration of that component could range anywhere from 0.02 percent to 0.1 percent depending on which end of the supplier's range is accurate. That's potentially the difference between clearing an allergen threshold and not.

Supplier's SDS range	Blend use level	Resulting range in finished product
1% to 5%	2%	0.02% to 0.10%
1% to 5%	5%	0.05% to 0.25%
1% to 5%	10%	0.10% to 0.50%

This is exactly why getting a tighter number from the supplier matters more as your use level climbs. A wide range barely matters at low use levels; it matters a lot once you're using a blend at meaningful concentration.

What to keep on file

Whatever value you land on, document how you got there. Note the SDS range, the blend's use level in your formula, your calculation, and whether you used a midpoint, a top-end estimate, or a supplier-confirmed exact figure. If a regulator or a retailer ever asks you to substantiate your ingredient declaration, that documentation is what makes the difference between "we have a defensible methodology" and "we guessed."

Getting this calculation right across every ingredient in every product is tedious by hand, which is part of why Cosmetic Comply builds the blend-to-finished-product math directly into its ingredient matching, so the concentration that reaches your filing reflects an actual, documented calculation rather than a rough guess made under deadline pressure.