Modern life affords us so little time to practice accumulating of merit and purification—and so many excuses to postpone for today. Who has time for daily offerings? It’s all most of us can do to fit in ten minutes of meditation. Isn’t it better to attend the next Vajrasattva Retreat or Empowerment than to take ten minutes a day for offerings?
Mandala set offerings is a practice that combines the best of meditation, mantra, purification and offerings in one very powerful act, and many teachers, as early as the great Lama Tsongkhapa, advocate this critical practice as a daily essential. It purifies negative karma and accumulates merit not just for ourselves, but for all beings. (Full Mandala offering method at end of this article.)
Mandala offering is a powerful method for accumulating extensive merit in a short time. The Tibetan word for mandala is kyil.kor: kyil is essence, kor is taking—taking the essence. The term means taking the essence on the base of offering a mandala, and what you get from this is merit—the cause. Therefore the essence you take is the generation of the whole path, from guru devotion up to enlightenment, as well as the result, the unification of the dharmakaya and rupakaya. The cause is merit, the path; and the result is enlightenment. — Lama Zopa Rinpoche 
Lama Tsongkhapa — One Million Mandalas
Even the great Lama Tsongkhapa, an enlightened being, practiced daily, focusing especially on purification and increasing of merit. Manjushri, at one point, advised the famous enlightened scholar to put aside scholarly pursuits and focus on purification and offering of the mandala. It was as a result of this, we are taught, that Tsongkhapa gained the higher realizations that he is known for in sutra in the tantra.
Lama Tsongkhapa did over one million mandala offerings, but because Lama Tsongkhapa was very poor, he used a stone base and stones. He did it until the skin tore off.
Daily Mandala Accumulates Vast Merit
Accumulation of merit and purification are two foundation practices of any Vajrayana Buddhist. We accumulate merit many ways—following the precepts prime among them—but extraordinary merit is accumulated through practice of Mandala offerings.
Doing the mandala offering is a way of clearing out all these negative states of mind. Here, “mandala” means the universe and everything in it. Instead of looking at things and saying, “Oh that’s good. I want it!” we train ourselves to think, “Oh, that looks good. I’m offering it to the Triple Gem.” — Venerable Thubten Chodron 
In doing a mandala offering, we offer the entire world, everything, not just our earth, but every one of the billions and trillions of planets throughout all universes. We visualize we are purifying incorrect motivations and receiving great blessings from the merit field. We offer the mandala from our hearts, to open our minds.
The Golden Ground and Mount Meru
The base of a Mandala set represents the golden ground of the world or universe. The first ring placed on the base represents the iron fence and the continents. The next rings represent Mount Meru. The Mandala top symbolizes all the precious things in all the universes, our own precious virtues.
One of the Most Important Daily Practices
Mandala offerings are considered one of the most important daily practices because the act accumulates different types of merit, but ordinary and primordial wisdom merit. We practice generosity, which overcomes the stingy or greedy mind full of desires and attachments. We then give up these attachments to the material by offering them to all beings in the universe. We visualize we are offering up the wealth of the entire universe to the Buddhas, the Bodhisattvas, the Dharma and the Sangha. Every day, this reminds us of the importance of good conduct, generosity and merit activities. Mandala gives us the motivation to achieve our goal of Buddhahood.
Venerable Thubten Chodron explains this merit accumulating practice in a teaching video:
It is both a purification and an offering. In making the daily offering to all beings, to the prosperity of all beings and the entire universe, we accumulate great merit. To advance in our own spiritual lives, we need only lightly shadow the example of Lama Tsongkhapa, being diligent in our daily and weekly practice. Prostrations, mantra, meditation and mandala offerings all accumulate merit and purify negative karma. An annual retreat, while of great value, is not as potent as a simple, short, daily practice.
Three Types of Mandala Offering
We are taught there are three types of mandala offerings, which fall into the broad descriptions of external, internal and secret. External is practiced by all Buddhists, a whole-hearted and generous offering based on sutra and suitable for everyone. Internal and secret are both unique to advance tantric practice.
Mandala is symbolic in all three types of offering. Meditating on the concept of Mandala is a worthwhile activity. Mandala itself, is a form of meditation, that illustrates for us the illusory nature of reality. Merit is accumulated by the act of offering benefits to the entire universe.
Each Day a New Offering
Unlike other offerings, we offer the same mandala offerings over again each time. We begin by purifying our incorrect motivations by wiping grain over the base of the mandala. We then draw blessings towards ourselves. Each day we offer the same semi-precious gems, grains and other materials, renewed and pure each time they are offered. This becomes a precious new offering. Important in renewing the offering is intention: the intention to make offerings, to purify negative karma, to offer merits to all beings suffering in the universe.
The mandala is a microcosmic illustration of the Buddhist cosmology. It need not be taken literally, and, in fact, helps us remember the nature of ultimate reality. It is not a physical representation of reality. Yet the symbolism is rich and worthy of hours of focused meditation. Using modern visualizations is not as valuable as trying to visualize the traditional cosmology.
At it’s centre is Mount Meru, not a literal mountain, but the centre of the entire universe. Surrounding Mount Meru are seven golden mountain chains. There are four levels of ground, four below the oceans and four above. Above all, is the sun and moon. The highest level in the mandala is the domain of the gods in the desire realm. There are four great continents and eight subcontinents on the great ocean surrounding Mount Meru. A great iron fence surounds the ocean, which rests on golden ground.
Detailed Mandala Set Offering Practice
Take your mandala set on your lap. Hold the mandala base in your right hand. If you have arthritis or can’t hold the base, place on a table.
NOTE: Do not speak the (brackets out loud — these identify where to pour the grain on the mandala). Italics are actions, not spoken.
Take some grain in your left hand and hold the mandala base. Take grain with your right hand and put it on the base. Wipe clockwise three times with your forearm, tipping the grain away from you. Visualize that you are purifying incorrect motivation.
Take grain and put it on the base again. Wipe anti-clockwise three times with your forearm, tipping the grain toward yourself. Visualize that you are receiving great blessings from the merit field to open your mind to offer the mandala from your heart.
Spread some grain over the base to symbolize the golden ground with precious jewels.
OM vajra ground AH HUM, mighty golden ground.
Place the first ring on the base. Take more grain and sprinkle it around the inside of the ring. This symbolizes blessing the iron fence that encircles the universe.
OM vajra fence AH HUM, the iron fence around the edge,
In the center is Mount Meru, the king of mountains (sprinkle in area 1, centre)
In the east the continent Lupapo (area 2)
East is toward you if the aim is receiving blessing power from the merit field. East is away from you if your aim is accumulating merit.
In the south Dzambuling (3)
In the west Balangcho (4)
In the north Draminyan (5)
In the east are the sub-continents Lu and Lupag (6 and 7) In the south Ngayab and Ngayabzhan (8 and 9) In the west Yodan and Lamchog dro (10 and 11) In the north Draminyan and Draminyan Gyida. (12 and 13)
Here are the precious mountain (14) The wish-granting tree (15) The wish-fulfilling cow (16) The unploughed harvest. (17)
Place the second ring on top of the grain-filled first ring. Visualize placing the eight precious objects belonging to a wheel-turning king who rules the four continents.
Here are the precious wheel (18)
The precious jewel (19)
The precious queen (20)
The precious minister (21)
The precious elephant (22)
The precious horse (23)
The precious general (24)
The great treasure vase. (25)
Continue on the inner area of the second ring. These eight symbolize the eight goddesses carrying eight different types of offerings:
Here are the goddess of beauty (26)
The goddess of garlands (27)
The goddess of songs (28)
The goddess of dance (29)
The goddess of flowers (30)
The goddess of incense (31)
The goddess of light (32)
The goddess of perfume (33)
Place the third ring on the grain-filled second ring. Place the grains to your left and right for the sun and moon. Place the banner of victory toward you to receive blessing power from the Buddhas and Bodhisattvas. If there is an obstacle, place the parasol toward you to symbolize receiving protecting power from the Buddhas and Bodhisattvas.
Here are the sun (34)
The moon (35)
The precious parasol (36)
The banner of victory in all directions. (27)
Place 38 the mandala top in the middle to symbolize the offerings of Samantabhadra.
In the center are the most perfect riches of gods and humans, with nothing missing, pure and delightful.
To my glorious, holy and most kind root guru, the lineage gurus and in particular to the great Lama Tzong Khapa, Buddha who is the king of sages, Vajradhara, and the entire assembly of deities, I offer these as a Buddha-field.
Please accept them with compassion, for the sake of migrating beings. Having accepted them, please bestow on me and on mother sentient beings abiding as far as the limits of space your inspiration with loving compassion.
• Visualize an enormous tree on the top of Mount Meru with many branches spreading throughout space. On each branch is Bodhisattva Samantabhadra, creating from his concentration innumerable priceless offerings to the Buddhas and Bodhisattvas. Transform the universe you have just created into a pure universe.
• Hold the mandala at your heart and offer it. Recite the mantra:
Idam guru ratna mandala kam nirya tayami
• Having made your request, tip the grain toward you, thinking that you are receiving their blessings. Visualize that from their hearts emanate brilliant white light and nectar which enter through your crown chakra, completely filling your body and mind and purifying all obstacles formed by negative karmas and delusions that hinder us from gaining realizations.
• The merit field dissolves into Buddha Shakyamuni, who is inseparable from your root guru. Buddha Shakyamuni comes above your head. At his heart, visualize a moon disk surrounded by the syllables of his mantra:
Om muni muni mahamuniye soha. (Recite this 100 times.)
Outside this mantra is the mantra of Lama Tzong Khapa, which represents the mantra of your own guru:
Om ah guru vajradhara sumati kiti siddhe hum hum. (Recite 100 times.)
• Perform your meditation practice then dissolve the merit field. At your heart is an open lotus, Guru Shakyamuni descends through your crown chakra and sits inside the lotus. Think that he becomes inseparable from your mind.
Collapsing the Mandala
It is important to face the Mandala towards you, with a cloth in your lap, and tip it into your lap so that all the offerings and rings fall towards you (caught in a cloth on your lap. You can then store the mandala by placing the rings inside the hollow of the base, and the grains or gems inside the rings, wrapped in your cloth.
 “Mandala Offering” Lama Zopa Rinpoche
 “The purpose of mandala offering” Venerable Thubten Chodron