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Warsaw Method Calculator

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Estimate fat-protein units (FPU) and extended-bolus insulin dosing guidance for high-fat, high-protein meals using the Warsaw method. Educational tool only.

Reviewed by the thecalcu.com team · Last updated July 14, 2026

Educational estimate only. The Warsaw (fat-protein unit) method is an advanced insulin-pump technique — individualize timing and dosing with your diabetes care team.

Fat in Meal
g
0150
Protein in Meal
g
0150
Insulin-to-Carb Ratio
g/unit
150

Fat-Protein Units (FPU)

0

Extra Insulin

0 u

Extended Bolus

None

No extension needed

—

What is a Warsaw Method?

A Warsaw Method Calculator estimates the additional insulin and extended dosing timing that may be needed for meals high in fat and protein, using the fat-protein unit (FPU) approach widely taught in insulin pump education. Unlike carbohydrate, which raises blood glucose relatively quickly, fat and protein are digested more slowly and can produce a delayed, prolonged glucose rise that standard mealtime dosing alone may not fully cover.

This calculator converts fat and protein grams into fat-protein units, with 100 kcal from combined fat and protein equal to 1 FPU, then estimates the extra insulin needed and a suggested extended bolus duration. It's meant to be used alongside standard carbohydrate-based dosing from the Insulin Dosage Calculator, not as a replacement for it.

Why Use a Warsaw Method Calculator?

High-fat or high-protein meals with modest carbohydrate content, like pizza, fried chicken, or a large steak dinner, can cause blood glucose to rise gradually over several hours after eating, sometimes catching standard carb-only dosing off guard. The Warsaw method addresses this by converting fat and protein calories into an insulin-equivalent unit that can be dosed and timed appropriately.

This calculator handles the fat-protein unit math instantly, converting grams of fat and protein into FPU, an estimated extra insulin amount, and a suggested extended bolus window, helping illustrate how this widely taught pump-therapy technique works in practice.

Who Should Use This Calculator?

  • Insulin pump users learning fat-protein counting as a supplement to standard carbohydrate-based dosing.
  • Diabetes educators demonstrating how the Warsaw method converts fat and protein into insulin-equivalent units.
  • Caregivers of someone using extended bolus features who want to understand the underlying calculation.
  • Students in diabetes education or nursing programs studying advanced insulin dosing techniques.

This calculator is strictly for educational purposes and is not medical advice, it is not a substitute for professional medical guidance or your prescribed insulin regimen. The Warsaw method is an advanced technique that should only be applied to real dosing decisions in partnership with your endocrinologist or diabetes care team, since incorrect application carries real risk of hypoglycemia or hyperglycemia.

What Insights Does the Warsaw Method Calculator Give You?

  • Fat-Protein Units (FPU), the primary result, converting your meal's fat and protein content into the standard FPU measure.
  • Carb-Equivalent Grams, the amount of carbohydrate the fat-protein load is treated as equivalent to, at 10 g per FPU.
  • Extra Insulin (Extended Bolus), the additional insulin estimated to cover the fat-protein load, based on your insulin-to-carb ratio.
  • Suggested Extended Bolus Duration, an estimated timeframe, in hours, over which the extra insulin might be spread using an extended or combo bolus feature.

Together these outputs illustrate how a high-fat, high-protein meal translates into additional insulin coverage beyond a standard carbohydrate-only dose.

How to use this Warsaw Method calculator

  1. Estimate the Fat in Meal, in grams, for the meal you're evaluating.
  2. Estimate the Protein in Meal, in grams, for the same meal.
  3. Enter your prescribed Insulin-to-Carb Ratio (grams of carbohydrate covered per unit of insulin).
  4. Review the Fat-Protein Units (FPU) result, shown as the primary output.
  5. Check the Extra Insulin and Suggested Extended Bolus Duration results, and discuss how to apply fat-protein counting to your actual insulin regimen with your diabetes care team.
Show formula & methodology ↓Show less ↑

Formula & Methodology

Fat-Protein Units (FPU) = [(Fat grams × 9) + (Protein grams × 4)] ÷ 100

Carb-Equivalent Grams = FPU × 10

Extra Insulin = Carb-Equivalent Grams ÷ Insulin-to-Carb Ratio

This follows the Warsaw method / fat-protein unit approach used in insulin pump education (based on the Bruttomesso et al. extended-bolus dosing pattern), where 1 FPU equals 100 kcal from fat and protein and is dosed like 10 g of carbohydrate, delivered as an extended bolus. Suggested duration follows a commonly taught rule of roughly 1 additional hour of extension per FPU, capped at 8 hours.

Worked example: a meal with 20 g fat and 30 g protein, insulin-to-carb ratio 1:10:
- Fat-protein energy = (20 × 9) + (30 × 4) = 180 + 120 = 300 kcal
- FPU = 300 ÷ 100 = 3 FPU
- Carb-equivalent = 3 × 10 = 30 g
- Extra insulin = 30 ÷ 10 = 3 units, suggested extended bolus over roughly 5 hours

Frequently Asked Questions

What is the Warsaw method?
The Warsaw method, also called the fat-protein unit (FPU) method, is an approach used in insulin pump therapy to dose additional insulin for meals high in fat and protein, which raise blood glucose more slowly and for longer than carbohydrate alone. It converts fat and protein calories into fat-protein units, dosed similarly to carbohydrate but delivered as an extended bolus over time.
How is a fat-protein unit (FPU) calculated?
One FPU represents 100 kilocalories from combined fat and protein, calculated as (fat grams × 9) plus (protein grams × 4), divided by 100. For example, a meal with 20 g of fat and 30 g of protein provides 300 kcal from fat and protein, or 3 FPU.
Why does fat and protein need separate insulin dosing from carbohydrate?
Carbohydrate raises blood glucose relatively quickly, which standard mealtime insulin is timed to match, but fat and protein are digested more slowly and can raise glucose gradually over several hours after a meal. Without additional coverage, this delayed rise can cause post-meal glucose to climb even when the initial carb-based dose was accurate.
How does this calculator estimate extended bolus duration?
This calculator uses a commonly taught rule of thumb where each fat-protein unit adds roughly one hour to the suggested extended bolus duration, starting around 3 hours for 1 FPU and capping at about 8 hours for larger fat-protein loads. Actual timing should always be individualized with your diabetes care team based on your own glucose response patterns.
How does the Warsaw method relate to standard insulin dosing?
The Warsaw method adds to, rather than replaces, standard carbohydrate-based dosing, you would typically calculate your regular meal and correction dose using the [Insulin Dosage Calculator](/insulin-dosage-calculator/), then add the extra insulin and extended timing suggested by the Warsaw method for high-fat, high-protein components of the meal.
What is an extended or combo bolus?
An extended (or square-wave) bolus delivers insulin gradually over a set period rather than all at once, while a combo bolus delivers part of the dose immediately and the rest gradually, both are features available on most insulin pumps. These delivery patterns are designed to better match the slower, prolonged glucose rise from fat and protein.
Is the Warsaw method only for insulin pump users?
The extended bolus feature this method relies on is primarily available on insulin pumps, though people using multiple daily injections sometimes apply modified versions of fat-protein counting with split or delayed injections under their care team's guidance. Pump users typically have the most precise ability to implement true extended dosing.
Does the Warsaw method apply to every meal?
No, it's specifically relevant for meals with substantial fat and protein content relative to carbohydrate, such as pizza, fried foods, or protein-heavy meals with minimal carbs. Meals that are primarily carbohydrate with low fat and protein typically don't need this additional adjustment.
How accurate are Warsaw method calculations?
Fat-protein unit dosing guidelines are based on general population patterns and clinical experience rather than a single precise formula, so individual glucose responses to fat and protein vary considerably. Many people refine their personal fat-protein dosing ratios over time in partnership with their diabetes care team using glucose monitoring data.
Why is there a strong safety disclaimer on this calculator?
Extended bolus dosing for fat and protein is an advanced diabetes management technique that carries real risk of hypoglycemia or hyperglycemia if applied incorrectly, so this tool is intended purely as an educational illustration of the method's math. Always work with your endocrinologist or diabetes educator before using fat-protein counting in your actual insulin regimen.
Also known as
fat protein unit calculatorFPU calculatorextended bolus calculatorWarsaw method insulinhigh fat meal insulin dosing