The Food Index is made up of a weighted average of all of the current foods listed in the Market Watch, with the starting date of this average on 12 January 2008, at an index of 100. The overall rising and falling of food prices is reflected in this index.
While specialised for just watching food prices, it is set up and adjusted in a manner similar to the Common Trade Index , and the divisor may be adjusted to include new food added by Jagex (see the FAQ for more information).
As of today, this index is 455.18 -1.34
Historical chart
Summary
Any suggested changes to this index should be added to the talk page .
Start date: 12 January 2008 (at index of 100)
Index today: 455.18
Change today: -1.34
Number of items: 19 (last adjusted on 12 January 2008)
Index divisor : 19.0000 (last adjusted on 12 January 2008)
List of items
This is the current list of items included in this index:
Icon
Item
Price
Direction
Low Alch
High Alch
Limit
Members
Details
Last updated
Bass 299 108 162 10,000 view 27 days ago
Bread 323 9 14 1,000 view 27 days ago
Cake 579 20 30 1,000 view 27 days ago
Cavefish 2,540 140 210 10,000 view 27 days ago
Chocolate cake 890 28 42 1,000 view 27 days ago
Great white shark 2,377 130 195 10,000 view 27 days ago
Lobster 141 107 160 10,000 view 27 days ago
Monkfish 388 92 138 10,000 view 27 days ago
Rocktail 4,690 240 360 10,000 view 27 days ago
Salmon 29 35 52 10,000 view 27 days ago
Saradomin brew (4) 19,880 80 120 1,000 view 27 days ago
Shark 1,933 120 180 10,000 view 27 days ago
Strawberries (5) 1,423 0 0 10,000 view 27 days ago
Swordfish 157 160 240 10,000 view 27 days ago
Tuna 37 48 72 10,000 view 27 days ago
Adjustments
20 May 2015
Adjusted index: Food Index
Adjustment date: 20 May 2015
Affected templates: Template:GE Food Index and Template:GE Food Index/Diff
Added item(s): 7 — Bread , Cavefish , Great white shark , Rocktail , Salmon , Saradomin brew (4) , Strawberries (5)
Removed item(s): 11 — Admiral pie , Garden pie , Kebab , Manta ray , Redberry pie , Roast bird meat , Sea turtle , Stew , Sweetcorn , Ugthanki kebab , Wild pie
Items before adjustment: 19
Items after adjustment: 15
Divisor before adjustment: 19.0000
Divisor after adjustment: 8.7619
Item
Base date
Base price
Price on adjustment date
Comments
Lobster
25 January 2008
175
196
Unchanged
Bass
195
225
Tuna
81
163
Swordfish
272
295
Monkfish
233
336
Shark
657
739
Cake
52
91
Chocolate cake
150
421
Ugthanki kebab
887
810
Removed item
Kebab
32
276
Sea turtle
1,264
2,690
Manta ray
1,794
1,907
Sweetcorn
135
43
Roast bird meat
22
19
Admiral pie
1,031
497
Wild pie
3,491
985
Redberry pie
381
1,280
Garden pie
657
475
Stew
100
1,102
Bread
–
–
433
Added item
Strawberries (5)
318
Saradomin brew (4)
9,762
Salmon
80
Cavefish
1,256
Rocktail
1,814
Great white shark
912
Calculations
From the old divisor obtained from the templates:
$ {div}_{\text{old}} = 19.0000 $
We need to calculate a new divisor:
$ {div}_{\text{new}} = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}} $
To calculate the new divisor, we need to find:
$ \begin{align} \sum \left ( \frac{p}{q} \right )_{\text{old}} & = \text{sum of ratios prior to change} \\ & = \text{sum of unchanged ratios} + \text{sum of removed ratios} \\ & = \left (\frac{196}{175} + \frac{225}{195} + \dots + \frac{421}{150} \right ) + \left (\frac{810}{887} + \frac{276}{32} + \dots + \frac{1,102}{100} \right ) \\ & = 42.27255853 \text{ (up to 8 d.p.)} \end{align} $
And also:
$ \begin{align} \sum \left ( \frac{p}{q} \right )_{\text{new}} & = \text{sum of ratios prior to change} - \text{sum of removed ratios} + \text{sum of added ratios} \\ & = \sum \left ( \frac{p}{q} \right )_{\text{old}} - \text{sum of removed ratios} + \text{number of added items} \\ & = 42.27255853 - \left ( \frac{810}{887} + \frac{276}{32} + \dots + \frac{1,102}{100} \right ) + 7 \\ & = 19.49428715 \text{ (up to 8 d.p.)} \end{align} $
Thus, the new divisor is:
$ \begin{align} {div}_{\text{new}} & = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}} \\ & = 19.0000 \times \frac{42.27255853}{19.49428715} \\ & = 8.7619 \text{ (4 d.p.)} \end{align} $