Ok, i understand that, but if i calculate with the default example in the calculator of 1 000 000 visitors and 4 minutes per session at 60% cpu load :

1 000 000 visits x 240 seconds x 20 h/s (arbitrary value, i don't know what is the average value of mining speed)
= 4 800 000 000 hashes solved

next, i use your formula : (solved_hashes)/(global_difficulty) * (block_reward) * 0.7

4 800 000 000 / 73598927024 * 5.5721 * 0.7 = 0.25 XMR
0.25 XMR * 295.5 (usd/xmr) = 75$

But in the calculator i got 936.28$ at this time.

I don't understand what i miss in my calculation, and why i've this gap between the results, can you enlighten me where is my error ?

Hi, i'm interested to integrate your webminer, but i'm really curious to know how you estime the reward with the calculator on your homepage ? I try to self estimate with the formula you give below in the page, i don't find the same result at all, could you elaborate ? Thanks for your answer.