Callaway · Iron set · 2021 · Previous model
Callaway Big Bertha B21 irons
Super game improvement, 5.0 of 5 for forgiveness
Callaway's super game improvement iron of 2021, with the most offset, the widest soles and the highest forgiveness on its own chart: 6.86 mm of offset at the 7-iron and a 29° 7-iron for a high flight. Callaway no longer sells the Big Bertha B21 new; the Big Bertha (2023) replaced it, and the Quantum Max OS replaced the Big Bertha (2023).
5.0 of 5 forgiveness score
$508.99 used at 2nd Swing Golf
New instead: Callaway Quantum Max OS, $1,099.99 at Golf Discount, 7 irons (4-PW), checked 2 Nov
Choose it if
- You often catch it thin or heavy and want the most help an iron gives.
- You catch the ground before the ball: the sole is wide, so it skids instead of digging.
- You play left-handed: it was made left-handed.
- You need a softer shaft: it came in Light, the flex Callaway's buying guide calls senior.
Choose something else if
- If your irons already fly high enough, the Big Bertha (2023) has the same kind of head with a stronger 27° 7-iron, for more distance.
- Class
- Super game improvement
- 7-iron loft
- 29°Every club's loft, lie and length
- Offset (7-iron)
- 6.9 mm
- Sole
- Wide
- Stock flexes
- Light, regular or stiff in graphite, regular or stiff in steel (Callaway gives its Light flex no letter)
- Hands
- Left or right; left-handed from the 4-iron to the SW; the 60° LW right-handed only.
- Used
- From $508.99 at 2nd Swing Golf, checked 31 Oct
What changed in the Quantum Max OS
Both are Callaway's super game improvement iron of their year with a 29° 7-iron: the Big Bertha (2023) between them strengthened it to 27°, and the Quantum Max OS went back to 29°, so a golfer who likes the B21's height finds it again in the newest set, not the 2023 one. The Quantum Max OS has less offset at the 7-iron (4.80 mm against 6.86 mm), an undercut cavity and a three-part Tri-Sole, where Callaway called the B21's soles noticeably wider. Its set adds a GW and stops at the SW; the B21 offered a 60° lob wedge, right-handed only.
Callaway no longer lists the B21, and no shop we checked has a new set, so it is bought used, for much less than a new Quantum Max OS. Choose it for the most offset and the widest soles on Callaway's 2021 chart for little money; choose the Quantum Max OS for a new set built to your hand, shaft and flex, or a GW in the set.
| Detail | Big Bertha B21 (previous) | Quantum Max OS (current) |
|---|---|---|
| Class | Super game improvement | Super game improvement |
| Forgiveness score | 5.0 of 5 | 4.5 of 5 |
| 7-iron loft | 29° | 29° |
| Offset at the 7-iron | 6.9 mm | 4.8 mm |
| Sole | Very wide | Tri-Sole |
| Stock flexes | Light, regular or stiff in graphite, regular or stiff in steel (Callaway gives its Light flex no letter) | Regular or stiff |
| Hands | Left or right; left-handed from the 4-iron to the SW; the 60° LW right-handed only | Left or right |
| Price new | No longer sold new | $1,099.99 at Golf Discount, 7 irons (4-PW), checked 2 Nov |
| Price used | From $508.99 at 2nd Swing Golf (5 clubs (6-PW), graphite, regular flex, average condition), checked 31 Oct | From $831.99 at 2nd Swing Golf (7 clubs (6-PW, AW, GW), steel, stiff flex, average condition), checked 31 Oct |
Loft, lie and length, club by club
| Club | Loft | Lie | Length | Offset |
|---|---|---|---|---|
| 4-iron | 19° | 60.5° | 38.75 in | 8.13 mm |
| 5-iron | 22° | 61.3° | 38.125 in | 7.75 mm |
| 6-iron | 25° | 62° | 37.5 in | 7.37 mm |
| 7-iron | 29° | 62.5° | 37 in | 6.86 mm |
| 8-iron | 33° | 63° | 36.5 in | 6.1 mm |
| 9-iron | 38° | 63.5° | 36 in | 5.46 mm |
| PW | 43° | 64° | 35.75 in | 4.7 mm |
| AW | 48° | 64° | 35.5 in | 3.81 mm |
| SW | 54° | 64° | 35.25 in | 3.18 mm |
| LW | 60° | 64° | 35 in | 2.54 mm |
Build a whole bag around it, or check the lofts in the bag you carry.
Use the iron finder to compare sets for your usual miss, and check the set makeup and loft gaps before ordering. Between a game improvement and a super game improvement head, this is how to tell which one your strike needs.
Big Bertha B21: the questions buyers ask
- Is the Callaway Big Bertha B21 forgiving?
- Yes. It is Callaway's super game improvement iron, with 6.9 mm of offset at the 7-iron, a wide sole and a 29° 7-iron. It scores 5.0 of 5 on our reading of what Callaway publishes about it, the top score among the iron sets we cover.
- Who is the Big Bertha B21 for?
- It suits golfers who often catch it thin or heavy and want the most help an iron gives.
- Does the Big Bertha B21 come in senior or ladies flex?
- Senior, yes, as Callaway names it: Light, the flex its buying guide calls senior. Callaway listed Light, regular (R) and stiff (S).
- Is the Big Bertha B21 sold left-handed?
- Left-handed from the 4-iron to the SW; the 60° LW right-handed only.
- What are the Big Bertha B21 lofts?
- 4-iron 19°, 5-iron 22°, 6-iron 25°, 7-iron 29°, 8-iron 33°, 9-iron 38°, PW 43°, AW 48°, SW 54°, LW 60°, as Callaway published them. The full table with lie, length and offset is above.
- Which clubs come in a Big Bertha B21 set?
- Callaway lists the 4-iron to PW, AW, SW and a 60° LW, the LW right-handed only; the standard set was seven clubs, 4-iron to PW. Callaway made the women's version as a separate set, the Big Bertha REVA, with lofts, swing weights and shafts set for women, so look for that name if you want the women's set.
- How much does the Big Bertha B21 cost?
- Callaway no longer sells it new. Used from $508.99 at 2nd Swing Golf, checked 31 Oct. Prices change; the seller's page has today's.
How the 5.0 adds up
The forgiveness score is our reading of what Callaway publishes about the head, from 1 to 5. It is not a test result. How every score works.
| Part | Points | Why |
|---|---|---|
| Head class | 4 | Super game improvement: the biggest, most forgiving iron head a maker sells. |
| Offset | +0.5 | 6.9 mm at the 7-iron, at or above our 4.5 mm mark. |
| Sole | +0.5 | Callaway calls the sole wide ("very wide"). |
| Forgiveness score | 5.0 | of 5 |
The score rates the head only. Hand, flex and price decide which version you buy, not how forgiving it is.
Specification sheet
| Maker | Callaway |
|---|---|
| Model | Big Bertha B21 |
| Model year | 2021 |
| Type | Iron set |
| Class | Super game improvement |
| Handicap range the maker states | – |
| Offset | 6.86 mm at the 7-iron (8.13 mm in the 4-iron down to 4.70 mm in the PW and 2.54 mm in the LW) |
| Sole | Very wide (maker's chart); noticeably wider soles |
| Moment of inertia (MOI) | – |
| Face technology | A.I. designed Flash Face Cup with a 360 Face Cup; Visible Tungsten Energy Core; urethane microspheres |
| Construction | A wide-soled Big Bertha head with extra offset, a face cup Callaway designed with AI, and a tungsten core you can see at the back of the head that sets the weight low and deep for an easier launch; urethane microspheres behind the face soften the feel. |
| Set makeup | Callaway lists the 4-iron to PW, AW, SW and a 60° LW, the LW right-handed only; the standard set was seven clubs, 4-iron to PW. Callaway made the women's version as a separate set, the Big Bertha REVA, with lofts, swing weights and shafts set for women, so look for that name if you want the women's set. |
| Clubs in the set | – |
| Stock steel shafts | KBS MAX CT80 |
| Stock graphite shafts | Callaway RCH 65i |
| Stock flexes | Light, regular or stiff in graphite, regular or stiff in steel (Callaway gives its Light flex no letter) |
| 7-iron loft | 29° |
| Hands | Left or right; left-handed from the 4-iron to the SW; the 60° LW right-handed only. |
| Men's or women's | – |
| List price when new | $899 for the seven-club set (2021 model); not a price today |
| Price at Callaway | – |
| Set price | – |
Compare with other super game improvement irons
No matching clubs. Clear the search or loosen the filters.
| Sole | Hand | Where to buy | |||||||
|---|---|---|---|---|---|---|---|---|---|
| 5.0 | Super game improvement | 28° | 4.8 mm | Wider | A · R · S · X | RH · LH | $1,299.99 at PGA TOUR Superstore 7 irons (5-9, PW, UW) · checked 2 Nov | ||
| 5.0 | Super game improvement | 32° | 4.6 mm | Wide | L · A · R · S · X | RH · LH | $749.95 at PXG 5 clubs (7-iron to sand wedge) at $149.99 each · checked 2 Nov | ||
| 5.0 | Super game improvement | 32° | 4.6 mm | Wide | L · A · R · S · X | RH · LH | $749.95 at PXG 5 clubs (7-iron to sand wedge) at $149.99 each · checked 2 Nov | ||
| 5.0 | Super game improvement | 31° | 5.7 mm | Wider: 23.9 mm at the 7-iron | R · S | RH | $962.50 at Mizuno 7 irons · checked 2 Nov | ||
| 4.5 | Super game improvement | 29° | 2.5 mm | Wide, sculpted | A · R · S | RH · LH | $599.99 at Tour Edge 7 irons · checked 2 Nov | ||
| 4.5 | Super game improvement | 29.5° | 5.2 mm | Skid sole, more bounce | A · R · S · X | RH · LH | $999 at Cobra 7 irons · checked 2 Nov | ||
| 4.5 | Super game improvement | 29.5° | 5.2 mm | Skid sole | L | RH · LH | $1,099 at Cobra 7 irons · checked 2 Nov | ||
| 4.5 | Super game improvement | not published | not published | Wide | R · S | RH · LH | $799.99 at Wilson 7 irons · checked 2 Nov |
Order: Forgiveness score first; on a tie, the set more golfers can buy, then a set that includes the long irons, then price. Use the arrows to sort. A dash means the maker does not publish it.
See all iron sets on the most forgiving irons page, or compare this club side by side. Waiting for a sale? The Black Friday golf club deals page has the price to beat on every club we price.
Sources
The specification comes from these pages; open the maker's page before buying, because prices and shaft options change. Check the exact shaft and hand at the shop before ordering.
- Callaway's specifications, archived copy of 14 Apr 2021
- Callaway Pre-Owned's specifications, archived copy of 25 Jun 2025
- Callaway's launch announcement
- Callaway's page on availability, archived copy of 15 Jun 2026
- Golf Discount's search results (checked 20 Oct)
- 2nd Swing Golf's used listings (checked 31 Oct)
- Callaway's page for the women's version, archived copy of 29 Oct 2020
- Pre-owned: seen at 2nd Swing Golf from $508.99 (checked 31 Oct)