Which ChatGPT does it work in?

ChatGPT Business and Enterprise: an admin enables Siglata once for the team. On Pro, Siglata is read-only, in developer mode. On Plus and Free, it doesn't work in ChatGPT on the web. In Codex, each person connects it, on every plan that includes Codex.

Does it work with my ERP?

Two ways: with the ERP's exports, as spreadsheets or CSV, and in the ERP's own pages, like Bling: your AI signs in to the portal with the login you or the company connected, reads lists and tables, clicks, fills in and posts, without seeing the password. The sales history by product works the same way, as a spreadsheet or CSV.

How do I calculate a demand forecast?

The simplest way is the moving average: add up the last three months' sales and divide by three. If the month is seasonal, multiply by the same month's index from the year before, which is that month's sales divided by the average of the three months before it. With an average of 124 and an index of 1.25, the forecast is 155.

How do I calculate a forecast in Excel?

In Excel, the three-month moving average is =AVERAGE(B2:D2), and the forecast with the index is =AVERAGE(B2:D2)*F2. Excel also has Forecast Sheet, on the Data tab (Microsoft Support, read on Oct 6, 2026). Your AI does the same math straight on the ERP export and saves the spreadsheet with the source of every number.

Know how much each product will sell next month.

Your AI reads the sales history exported from the ERP and saves each product's forecast, with the math and the source of every number.

Let's talk

How much will each product sell in October?

SiglataOctober forecast13 of 13 records

produto
"Café 500 g"
"Azeite 500 ml"
"Leite 1 L"
"Açúcar 1 kg"
"Detergente 500 ml"
"Óleo 900 ml"
"Ovos 12 un"
"Manteiga 200 g"
"Feijão 1 kg"
"Molho 340 g"
"Arroz 5 kg"
"Biscoito 400 g"
"Total"

Using Siglata · saving Jul, Aug, Sep, 3-month average, October index, October forecast, and Sales/dayUsed Siglata · saved Jul, Aug, Sep, 3-month average, October index, October forecast, and Sales/day in 13 records

I forecast 2,759 units across the 12 products in October. Biscoito 400 g rises to 155, with last October's index of 1.25. I saved v4 of the forecast spreadsheet, with the daily sales that restocking uses.

v3v4SavedPrevious version kept

Siglata

In SiglataOctober forecast13 records

—0

The October forecast table in Siglata, 13 records.
Row	Product	Jul	Aug	Sep	3-month average	October index	October forecast	Sales/day
1	Café 500 g	—150	—155	—160	—155	—1.20	—186	—6
2	Azeite 500 ml	—120	—124	—128	—124	—1.00	—124	—4
3	Leite 1 L	—640	—620	—600	—620	—0.90	—558	—18
4	Açúcar 1 kg	—320	—310	—300	—310	—0.90	—279	—9
5	Detergente 500 ml	—126	—124	—122	—124	—1.00	—124	—4
6	Óleo 900 ml	—190	—186	—182	—186	—1.00	—186	—6
7	Ovos 12 un	—285	—279	—273	—279	—1.00	—279	—9
8	Manteiga 200 g	—240	—248	—256	—248	—1.00	—248	—8
9	Feijão 1 kg	—210	—217	—224	—217	—1.00	—217	—7
10	Molho 340 g	—90	—93	—96	—93	—1.00	—93	—3
11	Arroz 5 kg	—300	—310	—320	—310	—1.00	—310	—10
12	Biscoito 400 g	—118	—124	—130	—124	—1.25	—155	—5
13	Total	——	——	——	——	——	—2,759	—89

TodayPREVISAO OUT (chute)Compatibility modeSaved 3 days ago

J7fx

ABCDEF1OCT FORECAST (guess)2Illustrative data.3DateInvoiceCodeProductQuantityTotal value4CAFÉ 500 G 1605Azeite 500 ml1286Leite 1 L6007Açúcar 1 kg 3008 Detergente 500 ml1229óleo 900 ml18210Ovos 12 UN273 11MANTEIGA 200 G 25612Feijão 1 kg22413Molho 340 g9614Arroz 5 kg 32015 Biscoito 400 g13016171819202122

Sheet1Sheet2 (2)copy of Sheet1DO NOT USE

Illustrative data. Drag the divider to compare.

The month's purchase comes from a guess

The sales history is in the ERP, but the forecast comes from a spreadsheet with numbers copied from last month. Nobody looks at what happened in the same month last year, and the product that sells more in October runs out again.

One question, the forecast per product

You ask how much will sell in October. Your AI adds up each product's last three months, applies last October's index and saves the forecast as a new version of the spreadsheet, with the previous one kept.

ChatGPT

How much will each product sell in October?

SiglataOctober forecast13 of 13 records

produto
"Café 500 g"
"Azeite 500 ml"
"Leite 1 L"
"Açúcar 1 kg"
"Detergente 500 ml"
"Óleo 900 ml"
"Ovos 12 un"
"Manteiga 200 g"
"Feijão 1 kg"
"Molho 340 g"
"Arroz 5 kg"
"Biscoito 400 g"
"Total"

v3v4SavedPrevious version kept

Ask anythingSiglata

The October forecast table in Siglata, 13 records.
Row	Product	Jul	Aug	Sep	3-month average	October index	October forecast	Sales/day
1	Café 500 g	—150	—155	—160	—155	—1.20	—186	—6
2	Azeite 500 ml	—120	—124	—128	—124	—1.00	—124	—4
3	Leite 1 L	—640	—620	—600	—620	—0.90	—558	—18
4	Açúcar 1 kg	—320	—310	—300	—310	—0.90	—279	—9
5	Detergente 500 ml	—126	—124	—122	—124	—1.00	—124	—4
6	Óleo 900 ml	—190	—186	—182	—186	—1.00	—186	—6
7	Ovos 12 un	—285	—279	—273	—279	—1.00	—279	—9
8	Manteiga 200 g	—240	—248	—256	—248	—1.00	—248	—8
9	Feijão 1 kg	—210	—217	—224	—217	—1.00	—217	—7
10	Molho 340 g	—90	—93	—96	—93	—1.00	—93	—3
11	Arroz 5 kg	—300	—310	—320	—310	—1.00	—310	—10
12	Biscoito 400 g	—118	—124	—130	—124	—1.25	—155	—5
13	Total	——	——	——	——	——	—2,759	—89

Every number with its source

Tap a forecast to see the three-month average, the October index and the row of every number in the history.

The October forecast table in Siglata, 13 records.
Row	Product	Jul	Aug	Sep	3-month average	October index	October forecast	Sales/day
1	Café 500 g	—150	—155	—160	—155	—1.20	—186	—6
2	Azeite 500 ml	—120	—124	—128	—124	—1.00	—124	—4
3	Leite 1 L	—640	—620	—600	—620	—0.90	—558	—18
4	Açúcar 1 kg	—320	—310	—300	—310	—0.90	—279	—9
5	Detergente 500 ml	—126	—124	—122	—124	—1.00	—124	—4
6	Óleo 900 ml	—190	—186	—182	—186	—1.00	—186	—6
7	Ovos 12 un	—285	—279	—273	—279	—1.00	—279	—9
8	Manteiga 200 g	—240	—248	—256	—248	—1.00	—248	—8
9	Feijão 1 kg	—210	—217	—224	—217	—1.00	—217	—7
10	Molho 340 g	—90	—93	—96	—93	—1.00	—93	—3
11	Arroz 5 kg	—300	—310	—320	—310	—1.00	—310	—10
12	Biscoito 400 g	—118	—124	—130	—124	—1.25	—155	—5
13	Total	——	——	——	——	——	—2,759	—89

Biscoito 400 g · October forecast 155

: 2026 sales: July 118, August 124, September 130 units.
: 3-month moving average: (118 + 124 + 130) ÷ 3 = 372 ÷ 3 = 124.
: October index: October 2025 sold 120; July to September 2025 sold 90, 96 and 102, an average of 96. 120 ÷ 96 = 1.25.
: October forecast: 124 × 1.25 = 155 units.
: Sales per day: 155 ÷ 31 days = 5.

Vendas_ERP_jul2025_set2026.csvv1 to · Biscoito 400 g rows from Jul 1 to Sep 30, 2026 · sums: 118, 124 and 130
Vendas_ERP_jul2025_set2026.csvv1 to · Biscoito 400 g rows from Jul 1 to Oct 31, 2025 · sums: 90, 96, 102 and 120
Previsao_de_demanda to · (company skill) · item 1: forecast = average of the last 3 months × the same month's index from the year before

In October 2025, the cookies sold 25% above the average of the three months before. The 2026 average alone would give 124; with the index, the forecast is 155.

v3v4Saved

Product · 3-month average · Jul to Sep 2025 (average) · Oct 2025 · Index · Forecast · Sales/day
Product	3-month average	Jul to Sep 2025 (average)	Oct 2025	Index	Forecast	Sales/day
Café 500 g	465 ÷ 3 = 155	150	180	180 ÷ 150 = 1.20	155 × 1.20 = 186	186 ÷ 31 = 6
Azeite 500 ml	372 ÷ 3 = 124	110	110	1.00	124	124 ÷ 31 = 4
Leite 1 L	1,860 ÷ 3 = 620	600	540	540 ÷ 600 = 0.90	620 × 0.90 = 558	558 ÷ 31 = 18
Açúcar 1 kg	930 ÷ 3 = 310	290	261	261 ÷ 290 = 0.90	310 × 0.90 = 279	279 ÷ 31 = 9
Detergente 500 ml	372 ÷ 3 = 124	115	115	1.00	124	124 ÷ 31 = 4
Óleo 900 ml	558 ÷ 3 = 186	170	170	1.00	186	186 ÷ 31 = 6
Ovos 12 un	837 ÷ 3 = 279	260	260	1.00	279	279 ÷ 31 = 9
Manteiga 200 g	744 ÷ 3 = 248	230	230	1.00	248	248 ÷ 31 = 8
Feijão 1 kg	651 ÷ 3 = 217	200	200	1.00	217	217 ÷ 31 = 7
Molho 340 g	279 ÷ 3 = 93	80	80	1.00	93	93 ÷ 31 = 3
Arroz 5 kg	930 ÷ 3 = 310	290	290	1.00	310	310 ÷ 31 = 10
Biscoito 400 g	372 ÷ 3 = 124	96	120	120 ÷ 96 = 1.25	124 × 1.25 = 155	155 ÷ 31 = 5

Download the example (.xlsx)

Illustrative data.

With the forecast saved, your AI works out what to restock.

The forecast method is written down

How many months go into the average and which index applies to each month live in a company skill. Each person works with their own access, and every change stays in the history, with the previous version kept.

Who accesses what

Row	Person	Inventory	Purchasing	Finance
1	You Admin	Can edit	Can edit	Can edit
2	Marcos Purchasing
3	Renata Finance
4	Rodrigo Sales

Click a level to change it. Each person's ChatGPT, Codex or Claude Code follows that person's access.

Today's activity

7:05 AMM
I forecast 2,759 units across the 12 products in October. Biscoito 400 g rises to 155, with last October's index of 1.25. I saved v4 of the forecast spreadsheet, with the daily sales that restocking uses.

Frequently asked questions

4 questions

Which ChatGPT does it work in?
ChatGPT Business and Enterprise: an admin enables Siglata once for the team. On Pro, Siglata is read-only, in developer mode. On Plus and Free, it doesn't work in ChatGPT on the web. In Codex, each person connects it, on every plan that includes Codex.
Does it work with my ERP?
Two ways: with the ERP's exports, as spreadsheets or CSV, and in the ERP's own pages, like Bling: your AI signs in to the portal with the login you or the company connected, reads lists and tables, clicks, fills in and posts, without seeing the password. The sales history by product works the same way, as a spreadsheet or CSV.
How do I calculate a demand forecast?
The simplest way is the moving average: add up the last three months' sales and divide by three. If the month is seasonal, multiply by the same month's index from the year before, which is that month's sales divided by the average of the three months before it. With an average of 124 and an index of 1.25, the forecast is 155.
How do I calculate a forecast in Excel?
In Excel, the three-month moving average is =AVERAGE(B2:D2), and the forecast with the index is =AVERAGE(B2:D2)*F2. Excel also has Forecast Sheet, on the Data tab (Microsoft Support, read on Oct 6, 2026). Your AI does the same math straight on the ERP export and saves the spreadsheet with the source of every number.

Want to see it with your company's history?

We'll show it with your ERP's sales export, in a WhatsApp conversation.

Let's talk contato@siglata.com