Additive Dosage and Cost-in-Use Calculator: 3 Dosage Units, Neat Additive vs Masterbatch

This additive dosage calculator turns one dosage, written in wt%, phr or ppm, into kilograms of active additive per tonne of compound, kilograms per batch and a cost in use per tonne, and compares a neat additive with a masterbatch delivering the same active level. A 1,000 ppm antioxidant level is 1 kg of active additive per tonne, but delivered through a 4 wt% masterbatch it is 25 kg of concentrate per tonne, so which route costs less depends on two prices that only the buyer knows.

The calculator holds no price data and never suggests a market price, and every formula it runs is printed under the output it produces.

What the Dosage and Cost-in-Use Calculator Returns#

The calculator returns 7 outputs from one dosage: the active level in wt% and ppm, active kilograms per tonne, kilograms per batch, the masterbatch let-down, cost per kilogram and per tonne of compound, and the break-even masterbatch price. Dosage is the quantity of an additive in the finished compound, and it is written in 3 units across the 43 families of plastic additives: wt% for thermoplastics, phr for PVC and rubber, and ppm for low-dose stabilizers and clarifiers.

The 7 outputs and the formula behind each one are listed in the table below.

Table T1. Outputs of the additive dosage calculator.

How to Use the Calculator in 7 Steps#

Run a dosage and cost comparison in 7 steps: choose the starting point, enter the dosage, enter the neat price, add the masterbatch, enter the volume, add the resin price, then read the comparison.

1. Choose the starting point: From active dosage when the target level is known, or From masterbatch let-down when a let-down is already running on the line.
2. Enter the dosage and pick its unit, wt%, ppm or phr; for phr, also enter the total phr of the whole recipe, 100 phr of resin included.
3. Enter your quoted price per kg of the neat additive, or leave it empty to see quantities only.
4. Tick Compare with a masterbatch route and enter the active content from the masterbatch technical data sheet and its price per kg.
5. Enter the compound volume in kg or t, and set whether it covers one batch or one year.
6. Enter the base polymer price per kg, an optional field, to see the cost above the resin each route replaces.
7. Read kilograms per tonne, kilograms per batch and cost per tonne for both routes side by side, then the difference and the break-even masterbatch price.

Three examples load the sourced dosages worked below, and none of them sets a price.

The Formulas Behind Each Output#

Every output rests on 2 conversions and 1 cost rule: dosage to weight percent, weight percent to mass, and cost per kilogram of compound as the weight fraction multiplied by the price. The calculator applies them in that order, and the formula under each result names the step it used.

From phr or ppm to weight percent#

A phr dosage becomes weight percent by dividing it by the total phr of the recipe, and ppm becomes weight percent by dividing by 10,000. The denominator in phr is the total, never 100, because the resin alone is fixed at 100 parts.

The unit itself is set out on PHR (parts per hundred resin): 0.70 phr in a 108.03 phr recipe is 0.648 wt%, not 0.70 wt%.

From weight percent to kilograms#

Active additive per tonne equals the weight percent multiplied by 10, because 1 wt% of 1,000 kg is 10 kg. The batch quantity scales the same fraction onto the compound volume you enter.

The same arithmetic in ppm is direct: 1 ppm is 1 g per tonne, so 1,000 ppm is 1 kg per tonne.

Masterbatch let-down and active level#

The active level a masterbatch delivers equals its let-down multiplied by its active content, divided by 100. Run in reverse, the let-down needed for a target level is that level divided by the active content, multiplied by 100.

The let-down here is the masterbatch share of the finished compound, so 25 kg per tonne of compound is 2.5 %, also written as a ratio n:1 with n = 100 / LDR - 1. Percent-on-resin conventions, presets per masterbatch type and the batch split into resin and concentrate run on the let-down ratio calculator.

Cost in use#

Cost in use per kilogram of compound is the weight fraction of each ingredient multiplied by its price, so an additive's share of compound cost is its dosage fraction multiplied by its price per kilogram.

A masterbatch with 4 wt% active content delivers 1 kg of active additive in 25 kg of concentrate, so it costs the same as the neat additive only when its price per kg is 4 % of the neat price.

What the Outputs Mean on the Production Line#

The comparison shows purchase cost at an identical active level, and the two routes differ in 3 further quantities: the carrier resin entering the compound, the mass the feeder has to handle and the resin each route displaces.

• Carrier resin. A masterbatch brings its carrier into the compound: 25 kg of a 4 wt% antioxidant masterbatch per tonne adds 24 kg of carrier resin (calculated here).
• Feeder mass. The masterbatch route doses 25 times the mass of the neat route in that example, a mass that is easier to meter: at ppm level, additives are dosed as masterbatch or a one-pack, and gravimetric loss-in-weight feeders are needed for ppm-level accuracy.
• Displaced resin. Every kilogram of additive or masterbatch replaces a kilogram of base polymer, so the optional base polymer field reports kg per tonne x (price - base polymer price) for each route.

Masterbatch active content typically runs 40 to 65 wt%, 15 to 80 wt% in extreme grades, at a let-down of 1 to 5 %, and the calculator flags any let-down outside that 1 to 5 % window. Typical active contents and masterbatch let-down ratios per masterbatch type are compared on the masterbatch hub.

Three Worked Dosage Examples#

The 3 examples loaded in the calculator cover a ppm-level additive masterbatch, a high-load black masterbatch and a phr-dosed PVC stabilizer, and each is worked here as quantities plus a cost formula, since the cost depends on your price.

Table T3. Three worked dosage examples (quantities calculated here from the sourced dosages).

1. Antioxidant masterbatch at 1,000 ppm#

Ampacet cites a 2.5 % let-down of an antioxidant masterbatch for 1,000 ppm of active antioxidant in the part, which implies a masterbatch holding 4 wt% antioxidant. The 4 wt% is calculated backward from those two figures, not a value the supplier publishes.

1. Active level. 1,000 ppm is 0.1 wt% and 1.0 kg per tonne of compound.
2. Masterbatch. 0.1 / 4 x 100 = 2.5 %, which is 39:1 and 25 kg per tonne, with 24 kg of carrier.
3. Break-even. The masterbatch matches the neat cost at 4 % of the neat antioxidant price per kg.

Which antioxidant grade fills that 1,000 ppm, and how primary and secondary grades are paired, is covered on antioxidants for plastics.

2. Black masterbatch for a PE pressure pipe#

A 35 wt% carbon black masterbatch let down at 5 to 6.5 % (19:1 to 14:1) gives about 1.75 to 2.3 wt% carbon black in the pipe, and ISO 4427-1:2019 sets 2.0 to 2.5 wt% for PE pressure pipe. The calculator loads the 6.5 % end: 2.28 wt% carbon black, 22.8 kg per tonne, from 65 kg of masterbatch carrying 42.3 kg of carrier (calculated here).

At the 5 % end the same masterbatch gives 1.75 wt%, below the ISO 4427-1:2019 band, and the calculator flags it. The break-even price for a 35 wt% black masterbatch is 35 % of the neat carbon black price per kg.

3. Tin heat stabilizer in a PVC pressure pipe compound#

The typical PVC pressure pipe compound in PPI TR-2-2023 Appendix C carries 0.70 phr tin heat stabilizer in a recipe totalling 108.03 phr, which is 0.648 wt% and 6.48 kg per tonne. A 500 kg batch takes 3.24 kg of stabilizer (calculated here), matching the batch column of the PHR to weight percent calculator.

This example runs without a masterbatch, because rigid PVC is dry-blended from a recipe written in phr. The full stabilizer package for that compound is set out on additives for PVC.

Data Sources and Limits of the Calculator#

The calculator contains formulas and 3 sourced examples, and no price, supplier or grade data. The example dosages are compiled from the sources cited on this page: the Ampacet antioxidant masterbatch and pipe compound guides, PPI TR-2-2023 and ISO 4427-1:2019.

The calculator's 5 limits are listed below.

• Purchase price only. Freight, handling, feeder equipment, dispersion quality and scrap are not in the cost.
• One additive at a time. A full recipe, with every row converted at once, belongs in the PHR to weight percent calculator.
• Mass basis only. Cost per litre needs density: cost per litre equals cost per kg multiplied by density, and fillers raise density, so cost per volume falls less than cost per kg.
• No compliance check. A level that fits a dosage band can still exceed a regulatory ceiling, which this calculator does not test.
• No market prices. Price fields are blank by design, and the currency selector only labels the result.

Feeding a ppm-level additive accurately is a compounding question, not an arithmetic one, and loss-in-weight feeding and masterbatch dosing are covered on plastic compounding.

Which Dosage Range Fits Which Additive Family?#

Additive dosage spans 4 bands, from ppm-level clarifiers and slip agents to plasticizers, fillers and mineral flame retardants at 10 to 70 % of the compound. The band decides which unit reads naturally and whether a masterbatch is the practical route.

Table T4. Dosage bands by additive family, with kg per tonne (calculated here).

The per-family ranges in full are collected on additive dosage levels in plastics, the formulation reference that pairs with this calculator.

How do you calculate additive dosage in kg per tonne?#

Multiply the dosage in weight percent by 10. 0.1 wt% is 1 kg of active additive per tonne of compound, and 2.5 wt% is 25 kg per tonne.

How do you convert ppm to kg per tonne?#

Divide ppm by 1,000, because 1 ppm is 1 g per tonne. 1,000 ppm is 1 kg per tonne and 0.1 wt%.

How do you calculate the cost in use of a masterbatch?#

Multiply the let-down fraction by the masterbatch price per kg to get the cost per kg of compound, then multiply by 1,000 for the cost per tonne. A 2.5 % let-down costs 25 times the masterbatch price per kg, per tonne of compound.

When is a masterbatch cheaper than the neat additive?#

On purchase price alone, a masterbatch is cheaper when its price per kg is below its active content fraction multiplied by the neat additive price. A 35 wt% masterbatch breaks even at 35 % of the neat price, and a 4 wt% masterbatch at 4 %.

Does the calculator include additive prices?#

No: the calculator holds no price data and suggests no market price, so every price comes from your own quote. Price trends and drivers per additive are described on plastic additive prices, and a quote for a specific grade can be requested through the plastic additive supplier finder.

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