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Layers 2 + 3 · mixing & carriers

DIY endurance fueling calculator

Pick what's in your pantry, list your carriers, set your session. The plan below splits the carbs across your bottles and flasks with the resulting concentrations. Works for cycling, running, triathlon, gravel, ultra — any endurance session where you fuel on the bike or on foot.

01 · My ingredients

Tick what you have on hand. The solver picks the best 1 or 2 to mix.

02 · My session
Glucose : fructose ratio

Rate-aware default: 2:1 G:F at ≤ 90 g/h, 1:0.8 above (Hearris 2022).

03 · GI tolerance

One knob that controls both the recipe pick and the concentration / osmolality warnings — drag right if your gut is sensitive today.

Trained gut Average Sensitive

Warns above 14 g/100 ml or 500 mOsm/L.

04 · My carriers

One row per bottle or flask. The solver fills bottles up to your GI tolerance ceiling and spills the rest into flasks as concentrate.

  • Bottle
  • Bottle
  • Soft flask

05 · Sodium target

→ 2100 mg total

Typical endurance range: 400–800 mg/h. Take this alongside the carb drink — via salt caps or a separate electrolyte sip — not mixed in.

Changes update the plan automatically. Use this if the plan looks stale.

Your plan

180 min · 90 g/h · 2:1 G:F

Up to date
270 g

total carbs over your session

Recipe

  • Table sugar (sucrose) 180.0 g
  • Maltodextrin (DE 10-15) 90.0 g
achieved ratio 2:1
avg bottle conc. 14.0 g/100ml
max mOsm/L 845
cost ~ 0.53 · saves ~ 21.07 vs gels

Session fluid

1.7 L total · 0.55 L/h

Average 16.4 g/100 ml across the session.

Doesn't change per-bottle warnings — the stomach feels each carrier's concentration as you drink it.

Take alongside

2100 mg sodium — via salt caps or a separate electrolyte sip. Don't mix into the carb drink.

Disclaimer — Educational tool, not medical advice. Self-experiment in training, not on race day. See the ingredient reference for source data.

Bottle A · 750 ml

  • table sugar (sucrose) 70.0 g
  • maltodextrin (de 10-15) 35.0 g

14.0 g per 100 ml · 296 mOsm/L

Isotonic — easy on the gut

Sip ~75 ml every 20 min

Bottle B · 750 ml

  • table sugar (sucrose) 70.0 g
  • maltodextrin (de 10-15) 35.0 g

14.0 g per 100 ml · 296 mOsm/L

Isotonic — easy on the gut

Sip ~75 ml every 20 min

Soft flask · 150 ml

  • table sugar (sucrose) 40.0 g
  • maltodextrin (de 10-15) 20.0 g

40.0 g per 100 ml · 845 mOsm/L

Concentrate flask — sip slowly, chase with water

Sip slowly — concentrate flask