# Calculating Enhanced Vegetation Index (EVI) using Sentinel-2 Level 1C, value problem

I am trying to calculate EVI values from Sentinel-2 Level 1C. When I calculate the EVI with this formula : (2.5 * ("Band 8" - "Band 4")) / ("Band 8" + (2.4 * "Band 4") + 1) I got values between -79.6462 to 22.6748. I used to know that EVI ranges between -1 to +1.

I tried this answer to Calculating 2-bands EVI from Sentinel-2, but I still have problems.

When I changed the formula as (2.5 * float("Band 8"/10000 - "Band 4"/10000)) / ("Band 8"/10000 + (2.4 * "Band 4"/10000) + 10000) my values are between -0.000169 to 0.0003. These are close but not expected values too.

Now I want to know if my procedure is okay and what the correct use of the formula for Level 1C is?

• Correct formula is as follows: 2.5 * float("Band 8"/10000 - "Band 4"/10000)) / ("Band 8"/10000 + (2.4 * "Band 4"/10000) + 1) Aug 8 at 20:20
• What software are you using to do that? Aug 8 at 21:14
• I am using python, in script I try this : evi = 2.5*(nir.astype(float)-red.astype(float))/((nir.astype(float)+(6.0*red.astype(float))+(-7.5*blue.astype(float))+1.0)) and the result is between -79.6462 to 22.6748. I divided all band values with 10000 before this line. Is it related with python? parentheses or something? Aug 8 at 23:18