Betting on the Grand National, Aintree's great steeplechase

The Grand National is the most famous steeplechase in the world and the centrepiece of Aintree's three-day meeting in April. It is a handicap: each horse carries a weight based on its official rating, so the best-rated horses carry the most and the lowest-rated carry the least. The aim is to give every runner a chance, and that is a large part of why the result is so hard to predict.

The race covers about four and a quarter miles, a long way even for a staying chaser, over two circuits of Aintree's Grand National course. After the last fence the runners face a long run to the line, including a famous bend known as the Elbow, where races are often won and lost by horses with stamina left in reserve.

The Grand National course has 16 fences. Fourteen are jumped twice and two, The Chair and the Water Jump, are jumped only once, which gives 30 jumps in total. Several fences are known by name:

• Becher's Brook, named after Captain Martin Becher, who fell there in the first running in 1839. Its drop on the landing side makes it the best-known fence in racing.
• The Chair, the tallest fence on the course, with an open ditch in front of it. It is jumped only on the first circuit.
• The Canal Turn, where runners must turn sharply left immediately after landing.
• Foinavon, named after the 100/1 winner of 1967, who avoided a pile-up at that fence on the second circuit.

The fences have been modified over the years with the welfare of horses and riders in mind. They remain a distinctive test, and how a horse has jumped in previous races is one of the first things worth checking in its form.

No horse is more closely linked with the Grand National than Red Rum. He won the race three times, in 1973, 1974 and 1977, and was second in the two years in between. His record of three wins still stands, and he is buried beside the winning post at Aintree.

The race has produced plenty of other stories since 1839, from long-priced winners such as Foinavon to the 1993 running, which was declared void after a false start. That history of surprises is part of the appeal: punters know that a horse at a big price has a real chance of running into the places.

The Grand National reaches far beyond regular racing fans. For many people it is the one race they watch each year, with office sweepstakes, family bets and a choice made on a name or a set of colours. That casual interest, added to the regular racing audience, makes it the single biggest betting event of the British racing calendar.

The size of the field plays its part. With up to 34 runners and a handicap that bunches them together, prices are spread out and even the favourite is usually at odds that would look generous in a smaller race. For punters, that means generous place terms but also a large number of horses that can win, fall or be brought down.

The Grand National is a handicap with well over 16 runners, so standard terms are four places at a quarter of the odds. In practice, many bookmakers go further and pay five, six or more places on the race. That makes each-way the natural bet for most punters.

Here is how it works with a £5 each-way bet, £10 in total, on a 25/1 shot at 1/4 the odds. If the horse wins, the win part returns £130 and the place part, settled at 25/4, returns £36.25, for £166.25 in all. If the horse finishes in the places without winning, you get £36.25 back. Our each-way calculator works out any combination of stake, odds and terms.

Ante-post bets need extra care. If more horses are entered than the safety limit allows, those lowest in the handicap miss out, and a horse can be withdrawn late because of the going or a setback. Unless your bet is struck on non-runner no bet terms, the stake is lost if your horse does not line up.

The essentials, in one place:

For more on the jumps season that leads up to Aintree, see our guide to the Cheltenham Festival, where some Grand National runners have a big outing a few weeks before Aintree.

Part of the National's charm is that anyone can pick the winner. The other side of that is that nobody can count on it. Treat your stake as the price of an afternoon's entertainment, decide how much you want to spend before the day and leave it there, however tempting the extra-place offers look.

If you open a new account for the race, set a deposit limit at the same time. Every UK-licensed bookmaker offers the tools to do it, and GambleAware and GamStop are linked in the footer of every page.