The data behind the prices

What we publish

One modelled price estimate per grade, per day, in pounds per tonne, with an uncertainty band around it.

The nine grades

• Ammonium NitrateAN_UK
• Granular UreaUREA_GRANULAR
• DAPDAP
• Muriate of PotashMOP
• Ammonium Nitrate (Imported)AN_IMPORT
• UANUAN
• Triple SuperphosphateTSP
• PolysulphatePOLYSULPHATE
• Nitrate SulphurNITRATE_SULPHUR

Every figure is an indicative, forecasted estimate. None of them is a transactable quote, and nothing on this site can be bought at the published price.

How the estimate is made

Each grade's estimate is driven by a mix of nutrient and commodity reference indices, calibrated on their month-over-month returns and applied to a UK delivered-to-farm reference level. The result is a daily figure that moves with the market, not a periodic print held flat between updates.

Nitrogen, phosphate and potash grades are driven by the European Commission's agri-food nutrient price indices. Muriate of potash is driven by the World Bank's commodity price series. Both are published under a Creative Commons Attribution 4.0 licence.

A grade is published as modelled only where its drivers beat a flat-carry baseline under walk-forward validation. Where they do not, the reference level is held flat and the grade is labelled accordingly. We would rather show you a flat line than a confident wrong number.

The band around each estimate widens with the time since the last reference update, so it tells you how much the model itself trusts the figure.

Sources and attribution

The reference indices behind the model are public, free to use, and named here so you can check our working.

What we changed

We do not republish either source. We calibrate month-over-month returns from them and apply those returns to a UK reference level to produce a daily modelled estimate. The figures on this site are ours, derived, and are not the source data.

No endorsement

Neither the European Commission nor the World Bank endorses Tilth, is associated with Tilth, or bears any responsibility for the estimates published here. Any error in our figures is ours.

Take the data

The daily estimate history for any grade is available as JSON. No key, no login, no rate card.

Endpoint

Example

Each point carries

• date: the day the estimate is for
• estimate_gbp_t: the modelled price in pounds per tonne
• band_low_gbp_t and band_high_gbp_t: the uncertainty band
• method: modelled, or flat_carry where the driver failed its gate
• signal_stage: how far the driver is through validation

Valid product codes

Licence and attribution

You may

• Read, quote and republish the figures, in print or online.
• Chart them, embed them, and build tools on top of them.
• Use them in research, commercially or otherwise.

You may not

• Present the figures as transactable quotes, or as anything other than modelled estimates.
• Represent Tilth as endorsing your product, or imply a partnership that does not exist.

Attribution

Credit Tilth and link back to this page. That is the whole price.

Who owns this

Tilth is owned by nobody who sells fertiliser. No merchant, no distributor and no manufacturer holds a stake in it, funds the index, or sees who reported a price. That is the entire point of it.

Questions, corrections, or a story

If you think a number is wrong, tell us. If you are writing about fertiliser prices and want the methodology explained properly, we will explain it.

Get in touch