Oil Blend Viscosity Calculator

How to Use This Tool

Enter the temperature of your oil blend, then add details for each oil you’re mixing. Select the oil type from the dropdown to auto-fill standard viscosity values, or enter a custom viscosity if using a less common oil.

Input the proportion of each oil using your preferred unit (weight percentage, volume, grams, or milliliters). Click Calculate to see your blend’s viscosity and recommended uses.

Use the Reset button to clear all inputs and start over. The Copy Results button lets you save your blend details to your clipboard for reference.

Formula and Logic

This calculator uses the Refutas equation to estimate blend viscosity, which is the industry standard for mixing petroleum and vegetable oils. The formula calculates the logarithmic average of each oil’s viscosity weighted by its proportion in the blend:

• Log₁₀(Blend Viscosity) = Σ (Weight Fraction of Oil ᵢ × Log₁₀(Viscosity of Oil ᵢ))

A simple temperature correction is applied to adjust viscosity for blends stored or used at temperatures other than 20°C (68°F), as oil viscosity decreases by approximately 2% per degree Celsius increase in temperature.

Proportions entered in volume units are converted to weight using a standard vegetable oil density of 0.92 grams per milliliter for accurate calculations.

Practical Notes

For home cooks, viscosity determines how an oil behaves in different recipes. Low-viscosity oils (under 50 cSt) flow easily and work best for salad dressings, cold dips, and drizzling over finished dishes. Medium-viscosity oils (50–80 cSt) are versatile for sautéing, baking, and stir-frying at moderate heat.

High-viscosity oils (over 80 cSt) are thicker and more stable at high temperatures, making them ideal for deep frying or roasting. When blending oils for frying, aim for a viscosity above 70 cSt to reduce smoke and breakdown during cooking.

Store blended oils in a cool, dark place to maintain consistent viscosity. Most cooking oils have a viscosity of 40–100 cSt at room temperature, so blends will fall within this range for everyday use.

Why This Tool Is Useful

Home cooks often blend oils to balance flavor, cost, and cooking performance. This tool eliminates guesswork by calculating exactly how your blend will perform, saving you from trial and error with ruined dishes or wasted oil.

It helps you adjust blends to suit specific recipes: for example, thinning a thick coconut oil blend with canola oil for baking, or thickening a light olive oil blend with avocado oil for high-heat frying.

You can also use it to replicate restaurant-quality oil blends at home, or to adjust recipes for dietary needs (e.g., blending olive and avocado oil for a heart-healthy high-heat cooking blend).

Frequently Asked Questions

What viscosity should my frying oil blend be?

For deep frying, aim for a blend viscosity of 70–90 cSt. This range ensures the oil is thick enough to coat food evenly without breaking down at high temperatures (350–400°F).

Can I use this tool for more than two oils?

This version is optimized for two-oil blends, which cover 90% of home cooking use cases. For blends with more oils, calculate the viscosity of a subset first, then use that result as a single oil input for the next blend step.

How accurate are the viscosity estimates?

Estimates are accurate within 5–10% for standard vegetable oils at room temperature. Accuracy may vary for cold-pressed or specialty oils, or for blends used at extreme temperatures (below 10°C or above 40°C).

Additional Guidance

Always measure oil proportions by weight for the most accurate results, as volume measurements can vary based on how tightly packed the oil is in the measuring tool. If using volume measurements, level off measuring spoons and cups for consistency.

When blending oils with very different viscosities (e.g., coconut oil at 45 cSt and olive oil at 84 cSt), mix thoroughly for 30 seconds to ensure the blend is homogeneous before using. Separation can cause inconsistent viscosity in different parts of the blend.

Label your blended oils with the viscosity and date of blending to track freshness and performance. Most blended cooking oils stay fresh for 3–6 months when stored properly.