Buying a few American candy bars as a treat for yourself is one thing. Ordering enough for 80 wedding guests, 150 people at an office party, or 30 children's party bags is a different job altogether, because this time you have a headcount, a budget and, most importantly, a fixed date that you have to work towards.

If you're buying candy for a specific event, timing is the first thing you need to think about, rather than what you're going to buy. Whether you're putting together a wedding sweet cart, an American-themed birthday, a Halloween event, a Fourth of July party, or treats for a school or club event, it's a good idea to order early rather than leaving it a little late and having the stress of not knowing if your order will arrive on time.

Start with the date and work backwards

When you're ordering from the US, the international journey is only one part of the timeline. First your order has to be processed by the retailer, then shipped within the US and received at your US address before it can begin its international journey. If you're buying from several stores, you may also need to wait for the final order to arrive before everything can be sent together.

Start with the date you actually need the candy, which shouldn't necessarily be the date of the event. If you're filling party bags, assembling favors, styling a candy table, or simply checking that everything has survived the journey, you want your order in your hands comfortably beforehand.

From there, work backwards to allow time for international shipping, processing and customs, delivery from the retailer within the US and any consolidation you plan to use. Carrier delivery estimates can be useful when you're choosing a service, but don't treat the fastest estimate as your event plan. Customs delays, bad weather, retailer dispatch times, stock problems and missed deliveries can all add time that isn't included in an international carrier's estimated journey.

As a rough guide, allow anything from a few days to a week or more for each retailer to dispatch your order and deliver it within the US. Stackry checks packages in on the business day they arrive, and consolidating several orders can take 2 to 4 business days. Stackry's international shipping options estimate 2 to 5 business days for express services such as DHL Worldwide Express or FedEx International Priority, around 3 to 15 for economy services, and up to 30 for the slowest mail options, with customs on top. Added together, even an express order can take two to three weeks from checkout to your door, before you add any contingency.

For an event with a fixed date, build in at least a couple of weeks of contingency rather than aiming for your candy to arrive a day or two before you need it. For a large wedding or important event, ordering even earlier gives you time to deal with a missing product or damaged parcel without turning your candy table into the most stressful part of the day.

The advantage with shelf-stable candy is that there is usually little benefit to cutting things fine. Check the best-by dates when you're buying, then get the order sorted early and cross it off your list.

How much candy do you need per guest?

There is a useful starting point here. For a candy buffet where guests can fill a small bag or help themselves during the event, allow around 4 to 6 oz (115 to 170g) per guest. Six ounces per person has long been used as a reasonable planning figure for a wedding candy buffet, although you can come down towards 2 to 3 oz if candy is only a small addition to a much larger dessert table.

That means a candy table for 80 guests needs roughly 20 to 30 lb (9 to 14kg) of candy at the 4 to 6 oz guideline. For 150 guests, you're looking at roughly 38 to 56 lb (17 to 26kg).

For pre-filled party bags, work from the bag rather than the buffet calculation. Decide exactly what will go into one bag, make a complete sample and multiply it by your guest count. If each bag contains eight individually wrapped pieces and you're expecting 60 guests, you need 480 pieces before you've allowed for extras.

Whichever approach you use, order a margin rather than the exact mathematical quantity. Guest numbers change, things get eaten while you're setting up and the occasional packet may arrive damaged. Around 10% extra is a sensible event-planning buffer, particularly if the candy is coming from another country and replacing it at short notice would be difficult.

Choose candy that can survive the journey

When you're buying for an event, the best candy isn't necessarily the most exciting thing you've found online. It also needs to arrive intact, look good on the day and cope with whatever weather it encounters along the way. Chocolate deserves particular care in warm weather; an international parcel can spend time in delivery vehicles, warehouses and other environments where you don't control the temperature, so there is always a melting risk. Choosing faster shipping can reduce the amount of time chocolate spends in transit, and ordering outside the hottest period where your event timing allows can help, but neither removes the risk completely.

Hard candy, gummies, individually wrapped sweets and similar shelf-stable products can therefore be easier choices for an event where appearance matters. Be more cautious with chocolate, very soft products and anything with a liquid or delicate center, particularly if you're ordering during hot weather or shipping to a hot climate.

It's also worth thinking about the physical size of your order. Giant tubs of inexpensive candy might look like excellent value on the retailer's website, but once you're shipping internationally, bulky low-value products can be poor candidates for an event order. Concentrate your US shopping on the products that make the table or party feel genuinely American, then use locally available items where the difference doesn't matter.

Ordering from more than one US store

You don't have to find one retailer that stocks everything. If you're using Stackry, eligible orders from different US stores can be sent to your Stackry address and consolidated into one international shipment once they've arrived. When you create your free account, you'll be sent your own delivery address at Stackry's logistics center in New Hampshire, which has no state sales tax, so purchases sent to your Stackry address have 0% US sales tax. Remember that import duties and taxes in your own country are separate and may still apply.

For an event, if you're ordering from multiple stores, the important thing is to place those retailer orders early enough for all of them to arrive before you need the consolidated parcel sent. One slow retailer can otherwise hold up the whole plan.

Check what you can ship

Food import rules vary by country, so check that the products you're buying are eligible for forwarding and permitted at your destination before placing a large event order. Stackry also maintains a current list of prohibited and restricted products, which is worth checking before you buy; this is particularly important if your order contains anything unusual rather than straightforward, commercially packaged, shelf-stable candy.

Have a backup plan

If 100 party bags are supposed to contain a particular US candy, don't order exactly 100 pieces and hope that every single one makes it from the retailer to your event intact. As well as adding an extra 10% into the order, consider in advance what you could substitute if something is unavailable.

If you're having a candy table, still make sure that you've got a backup plan in case your order doesn't arrive. Your guests won't know that you originally planned eight different products if seven arrive perfectly and one doesn't, but they will notice an empty jar.

It's vital that you don't leave your order until the final week. International shipping can be fast, but consolidation, forwarding and customs all add a bit of extra time to the process, and an event deadline isn't the time to test how fast it can be.

Ordering American candy for an event isn't difficult, but it does need a little more planning than ordering a box of treats for yourself. Start with your guest count, work out how much you actually need and choose products that are likely to travel well, then work backwards from the date and order early.

If the products you want are spread across several US retailers or the stores won't ship internationally, Stackry gives you a US address where eligible purchases can be received before being forwarded internationally. Just give yourself enough time to get everything together, because while you can change the candy on the table, you can't change the date of the wedding.