Geocoding is the bridge between the addresses humans use and the coordinates maps need. A spreadsheet of customer addresses, clinic locations, or delivery stops becomes genuinely mappable only after each row gains a latitude and longitude. Paid geocoding APIs do this at scale, but several free options handle small and medium lists perfectly well if you respect their limits.

The best-known free service is Nominatim, the geocoder behind OpenStreetMap. It is free to use, but it is a shared community resource with a published usage policy — roughly one request per second, no heavy bulk jobs without your own instance. For US addresses, the Census Bureau's geocoder is free and authoritative. QGIS also ships geocoding tools: the GeoCoding plugin and MMQGIS can send your address table through Nominatim and write the results straight into a point layer.

A practical no-code workflow starts in a spreadsheet. Clean your addresses first: split street, city, and postal code into separate columns, fix obvious typos, and keep a unique ID column so you can trace every result back to its source row. Then run the list through your chosen geocoder and export the result as a CSV with latitude and longitude columns. From there, convert the coordinates into a QGIS layer exactly as you would any GPS-style table.

Google Sheets users have a shortcut: geocoding add-ons that fill lat/lon columns directly in the sheet with a few clicks. These are convenient for lists of a few hundred addresses and need no coding. Whichever route you take, keep the raw addresses alongside the coordinates — you will need them when auditing the inevitable mismatches.

Match quality is where geocoding projects succeed or fail. Rural addresses, new developments, and inconsistent abbreviations ('St' vs 'Street', missing unit numbers) all lower the hit rate. Always review a sample of results on a map: a point landing in the wrong city is obvious visually and invisible in a spreadsheet. When an address fails to match, try the components separately — sometimes the street exists but the house number is too new for the reference data.

Finally, a word on etiquette and alternatives. Free geocoders survive because users behave: cache your results, never re-geocode the same list twice, and move to a paid tier or a self-hosted Nominatim instance before hammering public servers with tens of thousands of addresses. And if your addresses started life as field observations, consider skipping geocoding entirely next time — collecting coordinates directly with a GPS field app gives you positions that need no lookup at all.