What the calculator does, and what it does not do

Inputs and outputs

You choose 400–1,200 mL of water, 10–150 g of carbohydrate, an expected bottle duration, a pathway ratio and the ingredients available. The calculator returns the weight of each ingredient, total powder, glucose- and fructose-pathway equivalents, grams per hour, grams per 100 mL, sodium per bottle, sodium per litre, sodium per hour, estimated osmolality and a separate unitless particle score.

Changing a custom bottle's water volume leaves the selected carbohydrate and additive weights unchanged. Commercial-inspired presets scale their displayed amounts with water to preserve the reference concentration.

Carbohydrate pathway bookkeeping

The pathway labels are a simplified way to compare carbohydrate sources commonly discussed in endurance research. They are not direct measurements of intestinal absorption.

target fructose share = fructose ÷ (glucose + fructose)

The allocator searches only the selected ingredients. If they cannot make the chosen ratio, it shows the closest possible mixture and reports both the target and achieved ratios.

Particle score and estimated osmolality

The optional optimiser compares the ideal number of dissolved particles before digestion. Its relative factors are 1.0 for anhydrous dextrose and fructose, 0.526 for sucrose, 0.1 for representative DE10 maltodextrin, 2.45 for trisodium citrate dihydrate and 6.17 for table salt.

particle score = Σ(ingredient grams × relative factor) ÷ water litres

The score has no units and is only suitable for comparing recipes within Mix My Bottle. The osmolality estimate converts the same ideal particle model using anhydrous glucose as the reference:

estimated mOsm/kg added water = particle score × (1000 ÷ 180.156)

This assumes 1 mL of water weighs 1 g, complete dissolution, full electrolyte dissociation and representative DE10 maltodextrin. Alginate and pectin are excluded because chain length, substitution and ionisation vary by grade. Dextrose monohydrate also weighs differently from the anhydrous dextrose used in the model.

Sodium, concentration and intake checks

Custom recipes estimate sodium from table salt at 393.4 mg/g, trisodium citrate dihydrate at 234.5 mg/g and sodium alginate at a nominal 116 mg/g. Check the product label or certificate when alginate sodium matters because grades vary.

Drinks above 8 g carbohydrate per 100 mL are marked as concentrated fuel and need a separate fluid plan. The app gives context around the common 30–60 g/h range for exercise lasting about 1–2.5 hours and up to 90 g/h for longer efforts using multiple transportable carbohydrates. It does not present higher intake as established guidance.

Commercial-inspired presets

Tailwind, Maurten 320 and INFINIT Premium Fructose Fuel names identify the product style being referenced. Published label facts are kept separate from illustrative ingredient allocations. Exact formulations, flavourings, hydrocolloid quantities and manufacturing methods are proprietary and may change.

Commercial preset osmolality values use only the ingredient quantities shown. They are labelled carbohydrate-only where undisclosed electrolyte or hydrocolloid weights prevent a complete estimate. None of the presets is a product replica or endorsed substitute.