Upload your postcode figures
Drop in a CSV, check the postcode and value columns, name the dataset and import. Your figures are saved in your account and, when possible, added straight to the map you are editing.
Drop in your CSV
Choose Upload data. Drag one CSV file onto Drop your CSV here, or click the box to choose it. The first row should contain column headings. In Excel, use Save As → CSV UTF-8. You can also open Or paste cells from Excel and paste the headings and data together. Files can contain up to 25,000 rows and 8 MB.
Check the postcode column
GBMaps selects the column it thinks contains your postcodes. Check its blue heading in the small sample table. If the choice is wrong, pick the correct heading from Postcodes. Full postcodes and shorter postcode codes are recognised automatically.
Check the values column
Choose the column of numbers you want to add together, such as sales, orders or visits. Its sample heading is green. Keep one value column per dataset; import the file again with a different column if you want a second dataset. A zero remains zero; blank cells stay blank. Negative values, such as refunds, are allowed.
Read the sample
The table shows the first five rows of your file so you can check the choices. It is only a sample: all rows are checked when you import. Repeated postcodes are normal when several customers or orders share a postcode; their values are added together.
Name your dataset
Use a short, clear name such as Sales 2026 or Customer visits. This is both the name in My datasets and the label beside each territory total in your legend. You do not need to name the figure separately.
Import and use on this map
Click once to check the whole file, save the dataset and add it to your map. If the file is ready, the box closes and your totals appear in the legend. From the saved-map page the button is Import dataset: it saves the figures to your account for use when you next open a map. Use the map’s Save button to keep the dataset choice with that map.
If some rows need checking
You will see how many rows are ready and examples of anything wrong. Nothing is silently discarded. Correct the file and use Change file to upload it again, or tick Leave out these rows and import the rest. The download link gives the list of problem row numbers and reasons. A file with no usable values cannot be imported.
If a postcode needs one quick check
A compact code such as YO18 can mean district YO18 or sector YO1 8. If the file does not make this clear, GBMaps shows both examples and asks which you intended. This question is only shown when needed. Writing sectors with a space, or using a heading such as Postcode sector, avoids the ambiguity. Keep one kind of postcode in each file.
Use figures that can be added
Amounts and counts work well. Percentages and averages cannot simply be totalled: upload their underlying amounts or counts instead. Use a decimal point and up to four decimal places. Thousands commas and £ signs are accepted. A column with £ signs is displayed as pounds. Cells containing spreadsheet formulas need to be saved as their calculated values.