The amount of calcium carbonate in a Tums tablet varies by product: Regular Strength contains 500 mg, Extra Strength 750 mg, and Ultra Strength 1000 mg per chewable tablet.
You pop a Tums for heartburn and probably don’t think twice about what’s actually inside that chalky tablet. The active ingredient is calcium carbonate, and it turns out the dose changes depending on which box you grab from the shelf. That difference matters — both for how well it settles your stomach and for how much calcium you might be getting as a side benefit.
Here’s the straightforward breakdown: Tums comes in three main strengths, and each one delivers a specific amount of calcium carbonate. The Regular version is 500 mg, Extra Strength is 750 mg, and Ultra Strength is 1000 mg per tablet. That’s the short answer, but there’s more to know about what those numbers mean for your heartburn and your daily calcium intake.
Calcium Carbonate Per Tums Strength
Each Tums product lists its calcium carbonate content clearly on the label. The number you see — 500, 750, or 1000 — refers to the amount of calcium carbonate, which is the active antacid compound. But that’s not the same as the elemental calcium your body can actually use.
About 40% of calcium carbonate is elemental calcium, according to Medscape references. So a 500 mg tablet provides roughly 200 mg of elemental calcium, while the 1000 mg Ultra Strength gives about 400 mg. That distinction matters if you’re tracking your calcium intake for bone health alongside heartburn relief.
The FDA label for Regular Strength, published on DailyMed, confirms the 500 mg calcium carbonate and 200 mg elemental calcium per tablet. The Extra Strength and Ultra Strength numbers come from the manufacturer’s product pages.
| Tums Product | Calcium Carbonate | Elemental Calcium |
|---|---|---|
| Regular Strength | 500 mg | 200 mg |
| Extra Strength 750 | 750 mg | 300 mg |
| Ultra Strength 1000 | 1000 mg | 410 mg |
| Smoothies (per tablet) | 750 mg | 300 mg |
| Chewy Bites (per piece) | 750 mg | 300 mg |
Why The Strength Matters For Heartburn
You might grab any Tums box and assume they all work the same. The difference in calcium carbonate content directly affects how much stomach acid each tablet can neutralize. A higher dose means more neutralizing power per chew.
Here’s how the strengths typically match up with your symptoms:
- Occasional mild heartburn: Regular Strength (500 mg) is usually enough for mild, infrequent symptoms. One or two tablets after a heavy meal may settle things down.
- Moderate heartburn: Extra Strength 750 offers a middle ground. It delivers 50% more calcium carbonate per tablet than Regular, which can help when heartburn is more persistent.
- Frequent or severe heartburn: Ultra Strength 1000 packs the highest dose per tablet. The manufacturer notes that fewer tablets are needed, which can be convenient for repeated use.
- Onset of action: The manufacturer states that Tums works immediately by neutralizing acid on contact. The higher strengths don’t work faster, but they neutralize more acid per tablet.
- Sodium content: Extra Strength 750 contains about 2 mg of sodium per tablet, and Ultra Strength 1000 has 2 mg as well. That’s minimal for most people but worth noting if you’re on a strict low-sodium diet.
If you find yourself reaching for Tums more than a couple times a week, it’s worth talking to a doctor about your heartburn. Antacids treat symptoms, not the underlying cause of reflux.
How Calcium Carbonate Works As An Antacid
Calcium carbonate is a base that neutralizes hydrochloric acid in your stomach. When you chew a Tums tablet, the calcium carbonate dissolves and reacts with stomach acid to form calcium chloride, water, and carbon dioxide. That reaction raises the pH of your stomach contents, reducing the burning sensation.
Per the Calcium Carbonate Antacid Mechanism, this medication treats heartburn, indigestion, and upset stomach by lowering the acid level in your stomach. Cleveland Clinic notes that the same process also provides a source of dietary calcium, which is why some people use Tums as a supplement in addition to antacid use.
A 2022 review in PMC found that calcium carbonate also improved motor function of the esophagus in patients with heartburn, which helps clear acid from the esophagus more quickly. That second mechanism — beyond simple neutralization — may contribute to the relief people feel after chewing a tablet. The exact contribution of this esophageal effect compared to acid neutralization is still being studied.
Using Tums Effectively And Safely
Getting the most out of your Tums means using the right strength and following a few basic guidelines. The dosing is straightforward, but there are some important points to consider.
- Start with the lowest effective strength. For mild heartburn, Regular Strength is often enough. Using Ultra Strength when you don’t need it means taking more calcium than necessary, which can build up over time.
- Space out tablets from other medications. Calcium carbonate can limit the effectiveness of many drugs by increasing stomach pH, which decreases their absorption. This includes some antibiotics, thyroid medication, and iron supplements. A general rule is to take Tums at least two hours apart from other medications.
- Don’t exceed the labeled maximum. The label on each Tums product lists a maximum daily dose. For Regular Strength, that’s typically 10-12 tablets per day. Going beyond the label can lead to side effects like constipation or, with very high intake, milk-alkali syndrome.
- Chew thoroughly before swallowing. Tums tablets are designed to be chewed, not swallowed whole. Chewing breaks the tablet into fine particles that mix with stomach acid more effectively, providing faster and more complete neutralization.
The drug interaction with certain classes of medication is well-documented in clinical references. If you take prescription drugs regularly, check with your pharmacist about whether Tums could interfere with your specific regimen.
Using Tums As A Calcium Supplement
Because each tablet provides a meaningful amount of elemental calcium, some people use Tums as a casual calcium supplement. The numbers are substantial enough to contribute to daily intake, especially with the higher strengths. But there are important distinctions compared to standard calcium supplements.
The official FDA label provides the specific dosing details — the NLM’s Regular Strength calcium carbonate label confirms 200 mg of elemental calcium per 500 mg calcium carbonate tablet. Upper strengths follow the same 40% ratio. For comparison, a standard calcium supplement tablet often contains 500-600 mg of elemental calcium, much more than even two Ultra Strength Tums tablets.
Some people, particularly older adults and those with low stomach acid, may absorb calcium citrate better than calcium carbonate. That’s worth noting if you’re relying on Tums for bone health rather than occasional heartburn. Additionally, calcium carbonate can bind to iron, reducing its absorption because iron is best absorbed in an acidic environment. If you take iron supplements, separate them from Tums by at least two hours.
| Tums Strength | Tablets For 500 mg Elemental Calcium |
|---|---|
| Regular Strength | 2.5 tablets |
| Extra Strength 750 | ~1.7 tablets |
| Ultra Strength 1000 | ~1.2 tablets |
The Bottom Line
Tums delivers a predictable amount of calcium carbonate per tablet — 500 mg in Regular, 750 mg in Extra Strength, and 1000 mg in Ultra Strength. That’s roughly 200 mg, 300 mg, and 400 mg of elemental calcium respectively. Pick the strength that matches your typical heartburn severity, and check the label for maximum daily limits to avoid overdoing the calcium.
If your heartburn persists beyond occasional use, or if you’re thinking of using Tums regularly as a calcium source, your pharmacist or primary care doctor can help you sort out whether a different antacid or a dedicated calcium supplement would suit your situation better.