This is an online tool made by implementing the BSS Glossary Equations on p42, Reclining-Declining Dials. You can enter the details about your sundial location and it will calculate the angles you need. If you are making a large dial, you might find the X,Y co-ordinates easier to work with. The calculations work for horizontal, vertical and inclined dials, both South facing and declining. Please note that these angles are for Local Apparent Time (LAT) and do not take into account the Equation of Time, or whether Daylight Saving Time (called 'British Summer Time' in the UK) is in operation at your location. We have some Equation of Time charts you can freely use if that helps.